Substance Info: (and synonyms)
Hazelnut / Filbert / Barcelona Nut / Cob Nut

Background Info:

See: Hazelnut tree, for information on Hazelnut tree pollen

Common names: Hazel, Hazelnut, Filbert, Cobnut, Cob. The terms ‘Filbert’ and ‘Hazelnut’ are often used interchangeably to include all plants in the genus Corylus, such as C. silvestris, C. maxima and C. colurna.

Common hazelnut is classified as Corylus avellana, Filbert as Corylus maxima.
Other varieties are the Barcelona nut and Cob nut.

These wild nuts grow in clusters on the Hazel tree in temperate zones around the world. Hazel is an aggressive spreader and is particularly common in Europe as a wild growth, where it has played a significant role in the development of the present forest ecology. Archaeology shows that the nuts were a prehistoric food (and the wood a building material), and that tree populations were not adversely affected by land clearance for Neolithic farming.

The tree grows up to 8m and has a smooth, copper-coloured bark, which peals off in thin papery strips, and twigs covered in thick, reddish, glandular hairs. The fertilised flowers develop into clusters of nuts, which turn brown in October. The fruit, a 2 cm nut, is surrounded by a leafy bract (involucre) and ripens in late summer. The fuzzy outer husk opens as the nut ripens, revealing a hard, smooth shell, within which is a sweet, rich, grape-size nut within a bitter brown skin that is sometimes removed. Italy, Spain, France and Turkey lead the way in hazelnut production. The nuts generally fall in the autumn and are harvested from the ground and then shelled and dried.

Many Hazel trees grow wild, aggressively forming coppices and scrub. Particularly when cultivated, the nuts are used chopped, ground, roasted, blanched, sliced, and as flour and paste in all manner of sweets. They are also eaten whole as a snack (often among “mixed nuts”). During the Western holiday season, bowls of mixed nuts still in their shells are traditionally served, to be cracked with nutcrackers; Hazelnuts are prominent in these mixtures. Hazelnuts also add flavor and texture to savory items such as salads and main dishes.

Filbert nut is a variety of hazelnut that is popular in baking and as a snack. Hazelnut is widely used, and can be a "hidden" allergen.

Nougat, an ingredient in secondary products, e.g., confections, is a hazelnut product. Hazelnut oil obtained from the tree.


Adverse Reactions:


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This study wanted to derive threshold dose distributions for major allergenic foods and to elaborate the protein doses at which a proportion of the allergic population is likely to respond. Individual positive DBPCFCs were available for peanut (n = 135), cow's milk (n = 93), hen's egg (n = 53), hazelnut (n = 28), and cashew nut (n = 31). Fewer children were challenged with soy (n = 10) or walnut (n = 13). Threshold dose distributions showed a good statistical and visual fit. The protein dose at which 5% of the allergic population is likely to respond with objective reactions was 1.6 mg for peanut, 1.1 mg for cow's milk, 1.5 mg for hen's egg, 7.4 mg for cashew nut, and 0.29 mg for hazelnut. Thresholds for any symptom were on average 2 to 6 times lower than for objective symptoms. (Blom 2013 ref.28604 5)

Blom WM, Vlieg-Boerstra BJ, Kruizinga AG, van der HS, Houben GF, Dubois AE. Threshold dose distributions for 5 major allergenic foods in children. J Allergy Clin Immunol 2013 Jan;131(1):172-179

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Hazelnut (Corylus avellana) allergy varies from rather mild oral allergy symptoms to potentially life-threatening anaphylaxis and exhibits geographic and age-related variations. Severity of symptoms depends on the sensitisation profile of the patient and can partially be predicted using 'component-resolved diagnosis'. In Antwerp, Belgium, (young) children predominantly exhibit sensitisation to hazelnut storage proteins Cor a 9 and Cor a 11 that is unrelated to birch pollen allergy and is generally associated with a more severe clinical outcome on consumption on raw and processed hazelnut. In contrast, adults predominantly present with an oral allergy syndrome due to an extensive cross-reactivity between the labile Cor a 1.04 and Bet v 1, the major allergen from birch (Betula verrucosa) pollen. (Ebo 2012 ref.28702 7)

Ebo DG, Verweij MM, Sabato V, Hagendorens MM, Bridts CH, De Clerck LS. Hazelnut allergy: a multi-faced condition with demographic and geographic characteristics. Acta Clin Belg 2012 Sep-Oct;67(5):317-21.

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In the Mediterranean area, symptoms are more frequently severe and associated with sensitization to lipid transfer protein (LTP). This study compared patients with anaphylactic versus mild reactions to hazelnut and apple in The Netherlands, a birch-endemic area, with respect to sensitization to Bet v 1-homologues (i.e. PR10-proteins) and LTP. Methods: Twenty-one patients fulfilling the criteria for anaphylaxis and 21 with only mild symptoms (oral allergy) to hazelnut and/or apple were recruited. Specific immunoglobulin E to birch pollen, apple, hazelnut and PR10-proteins (rBet v 1, rPru p 1, rMal d 1 and rCor a 1) and recombinant LTP (rPru p 3 and rCor a 8) was measured by ImmunoCAP. Both mild and anaphylactic apple-allergic patients were sensitized to PR10-proteins, whereas only 1/7 of the mild and none of the anaphylactic apple-allergic patients was sensitized to LTP. In contrast, anaphylactic hazelnut-allergic patients displayed no such clear sensitization pattern: some were sensitized to both PR10-proteins and hazelnut LTP (1/9), and others to only LTP (2/9) or to only PR10-proteins (4/9) or to neither PR10-proteins nor LTP (2/9). Conclusion: This study shows that in a birch-endemic area, the sensitization profile to PR10-proteins and LTP in anaphylactic patients may differ between different plant foods. In this patient group, anaphylaxis to hazelnut can be LTP-associated, whereas anaphylaxis to apple is not. (Le 2012 ref.28208 7)

Le TM, van Hoffen E, Lebens AF, Bruijnzeel-Koomen CA, Knulst AC. Anaphylactic versus mild reactions to hazelnut and apple in a birch-endemic area: different sensitization profiles?. Int Arch Allergy Immunol 2012 Aug 31;160(1):56-62.

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The objective of this study was to establish and compare clinical threshold values for egg, hazelnut, milk and peanut, and correlating them to severity of symptoms. Seven hundred eighty-one challenges were performed in 487 patients (age range, 0.5-73.5 years). Using interval censoring survival analysis, the dose distribution of thresholds was fitted to a log-normal function. Symptom score was correlated to thresholds. Based on the 405 challenges resulting in objective signs, similar distribution of thresholds for hazelnut, milk, and peanut challenges were found, whereas individuals with egg allergy were bimodally distributed with a high or a low threshold. Eliciting dose in 10% (95% confidence interval) was 42.9 (24-76.8) mg whole eggs, 133.8 (95.9-186.6) mg whole hazelnut, 106.5 (59.7-190.6) mg roasted peanut, and 2.9 (1.5-5.4) mL milk. Adults showed more severe symptoms and signs than children, and peanut caused more severe reactions than the 3 other foods. Thresholds for the different foods were not comparable, and eliciting dose for the 4 foods differed, even if adjusted for protein content. Increasing age but not a low threshold dose is associated with severe symptoms on challenge.

Eller E, Hansen TK, Bindslev-Jensen C. Clinical thresholds to egg, hazelnut, milk and peanut: results from a single-center study using standardized challenges. Ann Allergy Asthma Immunol 2012 May;108(5):332-336

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Allergy to hazelnut can be severe and occur at young age. The objective is to investigate the pattern of hazelnut sensitization in infants with AD. Sera of 34 infants all under 1 year of age and suffering from AD were selected according to prior specific IgE results. Twenty-nine infants were sensitized to traditional food allergens, five were not. From the 29 infants with a sensitization to at least one food allergen, 20 demonstrated IgE reactivity to hazelnut: analyzed with the microarray immunoassay. Twelve (60%) of the children with IgE reactivity to hazelnut demonstrated sensitization to Cor a 9, the 11S legumin-like seed-storage protein from hazelnut. In these infants, no sensitization to Cor a 1, the homologue of the major birch pollen allergen Bet v 1 (Birch), or the lipid transfer protein (Cor a 8) from hazelnut was demonstrable. Half of the children sensitized to Cor a 9 demonstrated IgE reactivity to its homologue in peanut (Ara h 3) from which five were also sensitized to Gly m 6 from soy. None of the infants with AD without IgE reactivity to hazelnut demonstrated sensitization to Cor a 1, 8, or 9. In conclusion, young infants with atopic dermatitis sensitized to hazelnut can already display IgE reactivity to Cor a 9, a potentially dangerous hazelnut component. The mechanism(s) of this early sensitization and its clinical significance remain elusive. (Verweij 2010 ref.25247 7)

Verweij MM, Hagendorens MM, De Knop KJ, Bridts CH, De Clerck LS, Stevens WJ, Ebo DG Young infants with atopic dermatitis can display sensitization to Cor a 9, an 11S legumin-like seed-storage protein from hazelnut (Corylus avellana). Pediatr Allergy Immunol 2011 Mar;22(2):196-201.

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In this study aimed at finding new mustard allergens, 15 mustard-allergic patients with symptoms to peach were included. The mean age ranged from 18 to 54. The majority suffered from systemic symptoms when eating mustard (13/15) as well as OAS. All patients had OAS on eating fresh peach and 5/15 patients also suffered from systemic symptoms. Most of them also presented symptoms with other plant-derived foods, such as nuts (11/15), legumes (5/15), peanut (10/15), melon (12/15) or kiwi (9/15). The recombinant proteins, Sin a 3 and/or Sin a 4, were recognized by the IgE of sera from 11 out of 15 patients used in the study. The remaining patients recognized protein bands corresponding to major allergens such as Sin a 1 and Sin a 2 or not yet explored allergens. Sin a 3 shows 65% identity with amino acid sequence of Bra o 3 (nsLTP from cabbage, B. oleraceae var. capitata), and moderate, from 51% to 55% with Pru p 3, Mal d 3, Pru av 3, Fra a 3 or Cor a 8. Sin a 3 (nsLTP) and Sin a 4 (profilin) were identified as new mustard allergens and showed IgE cross-reactivity with fruits such as peach or melon, respectively. (Sirvent 2009 ref.24489 6)

Sirvent S, Palomares O, Vereda A, Villalba M, Cuesta-Herranz J, Rodríguez R. nsLTP and profilin are allergens in mustard seeds: cloning, sequencing and recombinant production of Sin a 3 and Sin a 4. Clin Exp Allergy 2009 Dec;39(12):1929-1936

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Immunological contact urticarial and/or protein contact dermatitis. Classically, the protein sources are divided into 4 main groups: group 1: fruits, vegetables, spices, plants, and woods; group 2: animal proteins; group 3: grains and group 4: enzymes. Taking into account the nature of the causal proteins, a wide variety of jobs can be affected. (Amaro 2008 ref.20923 7)

Amaro C, Goossens A. Immunological occupational contact urticaria and contact dermatitis from proteins: a review. Contact Dermatitis 2008 Feb;58(2):67-75.

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This study reports on a case of primarily airborne sensitization to LTP that might explain the geographical distribution of this type of food allergy. A 21-year-old woman began having severe perennial rhinitis 6 months after she started working in a wholesale fruit storehouse in Southern Italy where large amounts of fruits, including peaches, were handled; symptoms subsided when she left the workplace for >5 days and relapsed as soon as she was back at work. Later on, she developed severe food allergies to peach, hazelnut, peanut, apricot, plum and tomato. In vivo and in vitro analyses showed sensitivity to LTP. The nasal challenge with peach peel extract (6 mug protein) induced acute, severe respiratory symptoms. On immunoblot with peach peel extract patient's serum reacted uniquely against LTP, as demonstrated by inhibition assays with the recombinant peach protein. The authors conclude that LTP may induce sensitization via the respiratory tract due to inhalation of air-dispersed food particles, and this may precede the onset of food allergy. They state that if this way of sensitization were effective in the majority of LTP allergic patients (e.g. by exposure to peaches showing intact fuzz in areas where peaches are grown and directly sold on the market) then these findings could explain the strange geographical distribution of this type of food allergy. (Borghesan 2008 ref.21783 3)

Borghesan F, Mistrello G, Roncarolo D, Amato S, Plebani M, Asero R. Respiratory allergy to lipid transfer protein. Int Arch Allergy Immunol 2008 Jun 6;147(2):161-165

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Worsening of atopic dermatitis by hazelnut essence contained in hydroxyzine syrup. (Peroni 2007 ref.20924 7)

Peroni DG, Dall'Agnola A, Piacentini GL, Boner AL. Worsening of atopic dermatitis by hazelnut essence contained in hydroxyzine syrup. Acta Paediatr 2007 Nov;96(11):1710.

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Shortly after eating hazelnuts, a middle aged man developed lip and tongue swelling and complained of difficulty in breathing. On arrival at accident and emergency this had progressed so that he was unable to speak, demonstrated pronounced inspiratory stridor and had obvious tongue swelling, although air entry remained good with no wheeze on auscultation. This improved with repeated epinephrine administration. However, the fluctuating pattern to his condition continued with repeated development of upper airway oedema. Eight hours after initially ingesting the nuts the patient was given a simple mouthwash and advised to brush his teeth. When his mouth was rinsed, small fragments of nut were noted in the water. Following this he remained stable, with no further lip or tongue swelling and no recurrence of the stridor. (Jackson 2007 ref.28961 2)

Jackson M, Shaikh T. Mouthwash for anaphylaxis. Emerg Med J 2007 Dec;24(12):865.

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A 6 years old girl with a grass pollen allergy sensitised to group 1 and 5 allergens, and grass profilin, who presents and OAS to multiple fresh plant foods related to the profilin sensitisation. The girl presented with a mild atopic dermatitis and since the age of 3 years experencied rhinoconjunctival symptoms in spring. At 3.5 years she presented OAS after the intake of watermelon. Since then until the last visit she presented OAS with other plant foods including apple, kiwi, apricot, plum, peach, nectarine, pear, strawberry, grape, orange, tangerine, banana, tomato, cucumber and hazelnut. She tolerated processed fruits (juices, jam) and latex contact.
Skin prick tests to inhalants were positive to grass, olive, plane tree, mugwort, and plantain pollens. SPTs with commercial extracts of fruits were negative, but positive results were observed to some of them tested fresh (prick-prick). An oral challenge with fresh plum elicited oropharyngeal pruritus and labial angioedema. SPT and serum specific IgE to Pru p 3 were negative. SPT with nPho d 2 (date palm profilin) was positive. CAP to latex was 3.03 kU/L, with negative results to the recombinant latex allergens 1, 3, 5, 6.01 and 6.02. CAP inhibition assays of pollens, plant foods and latex were performed with rBet v 2 with the following inhibitions: > 85% to rBet v 2 and rPhl p 12, 40- 100% to watermelon, orange, apple, tomato, banana, 100% to latex, > 70% to mugwort, plane tree and olive pollens, no inhibition to grass and Phleum. (Rodriguez 2006 ref.23498 2)

Rodriguez del Rio P, Rodriguez-Jimenez B, Plaza A, Reig I, Sanchez-Lopez J, Vazquez-Cortes S, Martinez-Cocera C, Fernandez-Rivas M. Early onset of profilin sensitation. EAACI Congress, Vienna-Austria. 2006 Jun; Oral Abstract 1513.

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This study determined the clinical relevance of hazelnut sensitization and eliciting doses (EDs) in childhood by DBPCFC. Twenty-eight sensitized children age 4-16 years with suspected allergy to hazelnut were recruited. Atopic dermatitis the most frequently reported condition (86%). Sixteen children (57%) had seasonal rhinoconjunctivitis. Asthma- related symptoms were reported by 13 children (47%). Sixteen children (57%) did not show any reaction on
hazelnut ingestion during the challenge procedure. In 12 children (43%), hazelnut allergy was confirmed by challenge. Doses as large as 1 mg (0.16 mg protein) were tolerated by all children. Four children (4/12; 33%) reported only OAS without developing objective symptoms at doses starting from 10 mg. The interval between ingestion and OAS was always less than 10 minutes. Eight children (8/12; 67%) developed an objective reaction to hazelnut, such as systemic urticaria, rhinoconjunctivitis, vomiting, and dyspnea. ED for objective reactions ranged from 300 mg to 10 hazelnuts. In 5 children, the objective reactions were preceded by OAS on previous doses (100 mg to 3 g). In 3 children, OAS and objective symptoms developed on the same dose. Late reactions (as long as 24 hours after DBPCFC) were not reported. Skin prick test reactivity was significantly different between children without hazelnut allergy, children with only OAS, and children with objective symptoms; the latter group had the highest SPT reactivity. IgE reactivity to cross-reactive carbohydrate determinants of glycoproteins was negative in all but 1 patient and was not associated with the type of reaction. In our study, children with only OAS were all sensi- tized to birch pollen. In contrast, 3 of the children with additional objective symptoms to hazelnut had low or even undetectable birch pollen-specific IgE. This data indicates that sensitization to hazelnut is not clinically relevant in about half of the children. OAS was reported by all children with a reaction to hazelnut, at doses starting from 10 mg. This study suggests that the route of clinically relevant sensitization to hazelnut in children, in an area where birch trees are endemic, can be nonpollen-related. (Flinterman 2006 ref.16016 7)

Flinterman AE, Hoekstra MO, Meijer Y, van RR, Akkerdaas JH, Bruijnzeel-Koomen CA, Knulst AC, Pasmans SG. Clinical reactivity to hazelnut in children: association with sensitization to birch pollen or nuts? J Allergy Clin Immunol 2006 Nov;118(5):1186-1189

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In areas where birch trees are endemic, hazelnut allergy is often the result of primary sensitization to cross-reactive birch pollen allergen Bet v 1, usually resulting in mild oral allergy syndrome (OAS) in both adults and children. On the other hand, sensitization to hazelnut in early childhood has been related to sensitization to other tree nuts and peanut, which can all cause serious reactions. Children can be sensitized to hazelnut at an early age. Remarkably, a large proportion has never to their knowledge ingested hazelnut, and most allergic reactions to nuts in childhood occur after the first known exposure. (Flinterman 2006 ref.16016 8)

Flinterman AE, Hoekstra MO, Meijer Y, van RR, Akkerdaas JH, Bruijnzeel-Koomen CA, Knulst AC, Pasmans SG. Clinical reactivity to hazelnut in children: association with sensitization to birch pollen or nuts? J Allergy Clin Immunol 2006 Nov;118(5):1186-1189

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A "nut box" was constructed containing samples of common nuts and pine nuts. Nut-allergic and nonallergic children were asked to identify the nuts, and their responses were compared and correlated by age. Nut-allergic children were asked to identify the nut(s) that they should not eat. In general, children, including those who are allergic to nuts, can identify few nuts. This lack of recognition could put them at increased risk for unintentional ingestion. As part of an overall educational plan, nut-allergic children should be taught not only to avoid but also to identify the nut to which they are allergic. (Ferdman 2006 ref.15441 7)

Ferdman RM, Church JA. Mixed-up nuts: identification of peanuts and tree nuts by children. Ann Allergy Asthma Immunol 2006 Jul;97(1):73-77

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The syndrome of kiss-induced allergy (KIA) is an original form of allergy by proxy. Its true prevalence, probably underestimated, is not known but is reported to be between 1 and 10% in individuals suspected of being or actually allergic to food. The symptoms of KIA, local or regional, mild or moderate in 70% of the cases, can also turn out to be severe, with angioedema, bronchospasm, acute respiratory distress or anaphylaxis. FIA should be considered systematically in the following circumstances: 1) In pollen allergic patients who have an oral allergy reaction to fruits and vegetables; 2) patients who have severe food allergy and react to very small amounts of the responsible allergen; and 3) those who are having an “idiopathic” anaphylactic reaction. The diagnosis, above all clinical, requires a very careful history, noting that the symptoms appeared within minutes after a kiss. The time between eating the allergen and the kiss can be quite variable, from a few minutes up to two hours. Any food can be responsible, for example, common fruit (apple and kiwi), dried nuts (peanuts, almonds, hazel nuts, exotic nuts), fish, seafood, eggs, cow milk, etc. (Dutau 2006 ref.13850 9)

Dutau G, Rancé F. Le syndrome des allergies induites par le baiser / Kiss-induced allergy Revue francaise d allergologie 2006;46(2):80-84

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Pomegranate fruits have rarely been reported to cause immediate hypersensitivity after ingestion. A 21-year-old atopic man who experienced an anaphylactic reaction (urticaria, facial angioedema, and hypotension) after ingestion of pomegranate fruit. Three months later, he presented with a similar systemic reaction after hazelnut and peanut ingestion. SPTs were performed with fresh fruit, and SPTs with commercial extracts were performed for a panel of plant food and pollen. SPTs were positive for grass, olive, plane tree, cypress, and chenopodium pollen extracts and for hazelnut, peanut, peach, apple, maize, and rice food extracts and for fresh pomegranate. A 9 kDa and 29 kDa band was isolated. The 9-kDa binding band protein was also presented in other food extracts studied and in plane tree pollen extract and was completely inhibited with rCor a 8, a Lipid Transfer Protein. The cross-reactivity here appears to be as a result of the LTP. (Enrique 2006 ref.13198 4)

Enrique E, Utz M, de Mateo JA, Castello JV, Malek T, Pineda F Allergy to lipid transfer proteins: cross-reactivity among pomegranate, hazelnut, and peanut. Ann Allergy Asthma Immunol 2006;96(1):122-123

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A 42-year-old man developed generalised pruritus, itching of the throat, rhinitis, dyspnoea and dizziness 5 min after eating a few roasted Macadamia nuts. Skin prick tests were positive to Hazelnut and roasted Macadamia nut but negative for Peanut, Almond, Brazil nut and Walnut. A 34-year-old man repeatedly developed severe oral burning, itching and swelling after eating Hazelnut, Walnut, Brazil nut, Almond and Macadamia nut, but tolerating Peanut and Cashew nut. Skin prick test was positive to peanut, almond, hazelnut, Brazil nut and walnut but negative to cashew nut. A prick-to-prick was positive for Macadamia nut. Specific IgE to latex were 1.7 kU/l and negative to peanut, almond, hazelnut, Brazil nut, walnut, cashew nut and macadamia nut. (Lerch 2005 ref.10184 2)

Lerch M, Egger C, Bircher AJ. Allergic reactions to macadamia nut. Allergy 2005;60(1):130-1.

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A retrospective review of 213 Australian children with peanut or tree nut allergy was undertaken over a 42 month period. Anaphylaxis to cashew nut was more common than to peanut (74.1% v 30.5%). Of 213 patients seen with peanut and/or tree nut allergy, 177 patients (83.1%) had peanut allergy, 27 (12.6%) had cashew allergy, and 9 (4.2%; 2 each to almond and pecan, 1 each to hazelnut and walnut, and 3 were a mixture of nuts) had allergy to other tree nuts. A number of patients had anaphylaxis without cutaneous involvement. (Davoren 2005 ref.15757 0)

Davoren M, Peake J. Cashew nut allergy is associated with a high risk of anaphylaxis. Arch Dis Child 2005 Oct;90(10):1084-5.

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Grass allergy is the most common pollinosis in Northern Italy. Some patients with grass allergy show polysensitization against other pollens and plant-derived foods. In these patients oral allergic syndrome (OAS) is frequently associated. 56 children suffering from respiratory allergy due to grass pollens were enrolled. We found 14 children (25%) sensitized to Bet v 1 and 13 (23%) to Bet v 2; in 24 cases (42.3%) a sensitization to at least one of the 2 panallergens was observed. Five of the 14 cases (36%) sensitized to Bet v 1 showed food allergy and 8 (57%) food sensitization; 6 (46%) of the 13 children sensitized to Bet v 2 showed food allergy and 7 (54%) food sensitization; only one case of Bet v 1 specific IgE without food allergy or sensitization was seen. Sixteen subjects (29%) showed food allergy (group A); 20 children (35.5%) multiple sensitizations to inhalant and at least one plant-derived food (group B); 20 subjects (35.5%) only inhalant allergens (group C). Sensitization to Bet v 1 and Bet v 2 is from a statistical point of view significantly higher in groups A and B than in group C. In the 16 patients with food allergy hazelnut was the major triggering food (50%), followed by peanut (38%), kiwi (31%), apple and walnut (19%). Specific IgE for Bet v 1 is more associated with nuts and legumes, while Bet v 2 is more related to fresh fruit and vegetables. (Ricci 2005 ref.12840 5)

Ricci G, Righetti F, Menna G, Bellini F, Miniaci A, Masi M. Relationship between Bet v 1 and Bet v 2 specific IgE and food allergy in children with grass pollen respiratory allergy. Mol Immunol 2005 Jun;42(10):1251-7.

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Thirty-seven (20 boys, 17 girls) children with symptoms of only nocturnal enuresis were investigated with an allergy panel that included total IgE, 10 examples of inhalant-specific IgE, 10 examples of food-specific IgE, eosinophilic cationic protein (ECP) and Phadiotop. The same panel was studied in a control group of 18 children without nocturnal enuresis. The study concludes that evaluation of specific IgE showed that there may be a relationship between nocturnal enuresis and soybean and hazelnut food allergens. The authors caution that further studies are necessary to explain the underlying mechanisms and management of this disorder. (Mungan 2005 ref.12750 5)

Mungan NA, Seckiner I, Yesilli C, Akduman B, Tekin IO. Nocturnal enuresis and allergy. Scand J Urol Nephrol 2005;39(3):237-41.

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This study reports on a patient with anaphylaxis to coconut and oral symptoms to tree nuts, with positive skin test results to coconut and multiple tree nut extracts. IgE binding to 35- and 50-kDa protein bands in the coconut and hazelnut extracts was demonstrated and the presence of cross-reactive allergens between hazelnut (a tree nut) and coconut (a distantly related palm family member). (Nguyen 2004 ref.9090 7)

Nguyen SA, More DR, Whisman BA, Hagan LL. Cross-reactivity between coconut and hazelnut proteins in a patient with coconut anaphylaxis. Ann Allergy Asthma Immunol 2004;92(2):281-4

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A Spanish study, recruiting patients for a Hazelnut study, recruited 26 patients, including 10 patients with anaphylaxis. Cor a 8, the LTP allergen in hazelnut, was found to be causing these food-induced allergic diseases, including OAS and more severe symptoms in the majority of patients. (Schocker 2004 ref.8945 1)

Schocker F, Lüttkopf D, Scheurer S, Petersen A, Cisteró-Bahima A, Enrique E, San Miguel-Moncín M, Akkerdaas J, van Ree R, Vieths S, Becker WM. Recombinant lipid transfer protein Cor a 8 from hazelnut: a new tool for in vitro diagnosis of potentially severe hazelnut allergy. J Allergy Clin Immunol 2004;113(1):141-7

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In 2002, 107 cases were reported to the French Allergy Vigilance Network of which 59.8 % were cases of anaphylactic shock (one being fatal), 18.7% systemic reaction, 15.9% laryngeal angio-edema, 5.6% serious acute asthma (one fatal). Adults represented 69% of cases (74 cases). The most frequent causal allergens were peanut (14), nuts (16), shellfish (9) latex group fruit (9 patients), and most often in-patients allergic to latex: avocado (4), kiwi (2), fig (2), and banana (1). Next came lupine flour (7), wheat flour (7), celery (5) and snails (5), sesame (4), milk (3), buckwheat (3), fish (3), peach (2), chicken (2). Single observations included sulfites, quinine (an additive in a tonic drink), mustard, lentils, kidneys, pork, melon, grapes, pears, chicory, artichokes, oranges and Anisakis simplex. Four patients had an immediate post-prandial shock and were reported as idiopathic shock. The allergen was present in a masked form in 13% of cases: peanut (6 - with one fatal), lupine (4), sesame (3), and hazelnut (1).
In 4 cases of which one lethal a severe anaphylactic reaction occurred after consumption of macaroon in which the almonds have been replaced by peanuts paste without an adequate labeling. Two cases of anaphylactic shocks in hospitalized children were due to chocolate drink containing lupine flour. Both children were allergic to peanuts and AS occurred by cross allergy. A case of food allergy to hazelnuts is due to a mislabeling on chocolate packaging at Halloween. Two cases of severe anaphylaxis by proxy are reported: the incriminated allergenic peanuts. The patient presented the allergic reaction by contact with another person eating peanuts. (Moneret-Vautrin 2004 ref.10176 0)

Moneret-Vautrin DA, Kanny G, Morisset M, Rance F, Fardeau MF, Beaudouin E. Severe food anaphylaxis: 107 cases registered in 2002 by the Allergy Vigilance Network. Allerg Immunol (Paris) 2004;36(2):46-51

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A report on the sudden and unexpected death of an individual following the ingestion of hazelnuts and almonds, to which the individual was not previously known to be allergic. After eating a dessert, he experienced throat closing and swelling of his lips. He had previously experienced similar symptoms after ingesting peanuts, and after confirming that none were present in the food, he relaxed. He then collapsed during vigorous dancing. The death was not associated with cutaneous or laryngeal manifestations of anaphylaxis. (Flannagan 2004 ref.20217 7)

Flannagan LM, Wolf BC. Sudden death associated with food and exercise. J Forensic Sci 2004 May;49(3):543-5.

[ 25 / 51 ]

Cor a 1.04 has been identified as the major hazelnut allergen in 65 European patients with positive double-blind, placebo-controlled food challenge results to hazelnut. The 11S globulin Cor a 9 was shown to be a pollen-independent hazelnut allergen in the United States, whereas preliminary data suggest the lipid transfer protein (LTP) as an important birch pollen-unrelated hazelnut allergen in Europe. This study recruited 26 Spanish patients allergic to hazelnut without birch pollen allergy, including 10 patients with anaphylaxis, and identified and cloned the major food allergen, Hazelnut LTP Cor a 8 a 9kDa protein, in this study population. Of 26 cases, history revealed 10 (38%) cases of anaphylaxis, 8 (31%) cases of OAS, 6 (23%) cases of angioedema, and 2 (8%) cases of urticaria, and 1 of food-dependent, exercise-induced anaphylaxis. The prevalence of specific IgE antibody reactivity to LTP was 62% in hazelnut extract and 77% when recombinant LTP was tested by means of immunoblotting. IgE immunoblot inhibition with hazelnut extract showed that natural Cor a 8 and rCor a 8 shared identical epitopes. Only one patient had positive reactivity to Cor a 1.04, and no patients had positive reactivity to Cor a 2. Two sera bound to high-molecular-weight allergens. Cor a 8 is thus a relevant allergen for a majority of Spanish patients with hazelnut allergy that can cause severe allergic reactions. (Schocker 2004 ref.8945 8)

Schocker F, Lüttkopf D, Scheurer S, Petersen A, Cisteró-Bahima A, Enrique E, San Miguel-Moncín M, Akkerdaas J, van Ree R, Vieths S, Becker WM. Recombinant lipid transfer protein Cor a 8 from hazelnut: a new tool for in vitro diagnosis of potentially severe hazelnut allergy. J Allergy Clin Immunol 2004;113(1):141-7

[ 26 / 51 ]

The perception of food-related symptoms is common among children and adolescents from the general population. Foods most commonly identified by oral challenges were apple, hazelnut, soy, kiwi, carrot and wheat. (Roehr 2004 ref.12297 8)

Roehr CC, Edenharter G, Reimann S, Ehlers I, Worm M, Zuberbier T, Niggemann B. Food allergy and non-allergic food hypersensitivity in children and adolescents. Clin Exp Allergy 2004 Oct;34(10):1534-41.

[ 27 / 51 ]

Where trees of the family Betulaceae (e.g., birch, alder, hazel and hornbeam) are prevalent, the cross-reactivity between (sensitizing) pollen and nut allergens can be the leading cause of food allergies. (Roux 2003 ref.8304 0)

Roux KH, Teuber SS, Sathe SK. Tree nut allergens. Int Arch Allergy Immunol 2003;131(4):234-44

[ 28 / 51 ]

Some patients with allergy to hazelnut may be allergic to the nut, others to the tree pollen, and still others to both. The type of allergic reaction and the specific allergens recognized can vary considerably from one geographic area to another. (Roux 2003 ref.8304 2)

Roux KH, Teuber SS, Sathe SK. Tree nut allergens. Int Arch Allergy Immunol 2003;131(4):234-44

[ 29 / 51 ]

In 5/17 Danish and Swiss hazelnut-allergic patients tested for reactivity to Cor a 1.0401 (Bet v 1-like), Cor a 2 (profilin), and Cor a 8 (LTP), the DBPCFC with the roasted nuts were positive. The symptoms were generally mild and included OAS (oral allergy syndrome) in all patients. Roasting of the nuts significantly reduced the allergenic activity evaluated by SPT, HR, specific IgE, and IgE-inhibition. Five patients still reacted to hazelnuts after thermal treatment, suggesting that traces of pollen-related allergens remained active in the roasted nuts used. This means that tolerance to processed foods has to be evaluated individually in patients even if they are sensitized to labile pollen- related allergens.

16 (94%) reacted with Cor a 1.0401, 7 (41%) with Cor a 2, and none with Cor a 8. Cor a 9 was not tested. Roasting of peanuts significantly decreased allergenicity including to Cor a 1.0401 and Cor a 2. (Hansen 2003 ref.7551 5) (Mari 2005 ref.11706 0)

Hansen KS, Ballmer-Weber BK, Luttkopf D, Skov PS, Wuthrich B, Bindslev-Jensen C, Vieths S, Poulsen LK. Roasted hazelnuts - allergenic activity evaluated by double-blind, placebo-controlled food challenge. Allergy 2003;58(2):132-138

[ 30 / 51 ]

Hazelnuts are a common cause of food allergy. Allergic reactions to hazelnuts range from oral allergy syndrome caused by cross-reactivity between tree pollen and hazelnut proteins to severe anaphylactic reactions. In 17 patients challenged by DBPCFC with roasted nuts 5 were positive. The symptoms were generally mild and included OAS (oral allergy syndrome) in all patients. Roasting of the nuts significantly reduced the allergenic activity evaluated by SPT, HR, specific IgE, and IgE-inhibition. (Hansen 2003 ref.7863 2)

Hansen KS, Ballmer-Weber BK, Lüttkopf D, Skov PS, Wüthrich B, Bindslev-Jensen C, Vieths S, Poulsen LK. Roasted hazelnuts--allergenic activity evaluated by double-blind, placebo-controlled food challenge. Allergy 2003;58(2):132-8

[ 31 / 51 ]

Hazelnuts are a common cause of food allergy. Allergic reactions to hazelnuts range from oral allergy syndrome caused by cross-reactivity between tree pollen and hazelnut proteins to severe anaphylactic reactions. Extrapolation of the dose-response curve showed that 50% of our hazelnut-allergic population will suffer from an allergic reaction after ingestion of 6 mg (95% CI, 2-11 mg) of hazelnut protein. (Beyer 2002 ref.6876 1)

Beyer K, Grishina G, Bardina L, Grishin A, Sampson HA. Identification of an 11S globulin as a major hazelnut food allergen in hazelnut-induced systemic reactions. J Allergy Clin Immunol 2002;110(3):517-23

[ 32 / 51 ]

All 7 Italian patients with hazelnut allergy but without birch pollen allergy had specific IgE antibodies to a 9-kd hazelnut allergen, presumably LTP, in contrast to not one single LTP-positive serum sample out of 65 patients allergic to hazelnuts with birch pollen allergy from Milan, Copenhagen, and Zurich. Patients with severe anaphylactic reactions to hazelnut showed specific IgE reactivity to a 9-kd allergen, which was heat stable and, when purified, corresponded to an LTP. Hazelnut-allergic patients, allergic as a result of LTP-reactive IgE and not primarily a Bet v 1 homologue (Bet v 1). (Pastorello 2002 ref.5340 4)

Pastorello EA, Vieths S, Pravettoni V, Farioli L, Trambaioli C, Fortunato D, Lüttkopf D, Calamari M, Ansaloni R, Scibilia J, Ballmer-Weber BK, Poulsen LK, Wütrich B, Hansen KS, Robino AM, Ortolani C, Conti A. Identification of hazelnut major allergens in sensitive patients with positive double-blind, placebo-controlled food challenge results. J Allergy Clin Immunol 2002;109(3):563-70

[ 33 / 51 ]

Twenty-nine hazelnut allergic patients had a positive challenge to increasing dose challenges with hazelnut. Itching of the oral cavity and/or lips was the first symptom in all cases. Additional gastrointestinal symptoms were reported in five patients and difficulty in swallowing in one patient. Lip swelling was observed in two patients, followed by generalized urticaria in one of these. Threshold doses for eliciting subjective reactions varied from a dose of 1 mg up to 100 mg hazelnut protein (equivalent to 6.4-640 mg hazelnut meal). (Wensing 2002 ref.7553 2)

Wensing M, Penninks AH, Hefle SL, Akkerdaas JH, van Ree R, Koppelman SJ, Bruijnzeel-Koomen CA, Knulst AC. The range of minimum provoking doses in hazelnut-allergic patients as determined by double-blind, placebo-controlled food challenges. Clin Exp Allergy 2002;32(12):1757-62

[ 34 / 51 ]

It appears that threshold levels for subjective reactions in hazelnut allergic patients vary from less than 1mg up to doses probably higher than 100mg of raw hazelnut protein. (Wensing 2001 ref.4042 4)

Wensing M., Penninks A.H., Hefle S.L., Akkerdaas J.H., van Ree R. et al. Determination of threshold levels of patients with hazelnut allergy using double-blind placebo-controlled food challenges (DBPCFC”S) [Poster] 8th International Symposium on Problems of Food Allergy, Venice. 2001, March 11-13.

[ 35 / 51 ]

Anaphylaxis in a 20-year-old girl occuring 1 hour after ingestion of string bean. Symptoms were gastroenteritis, generalised urticaria and collapse. She reacted to boiled string bean, inducing a stronger reaction than raw string bean. She also developed urticaria from fresh fennel, boiled cabbage, mustard, commercial hazelnut cream and commercial pear juice. (Asero 2001 ref.4132 9)

Asero R, Mistrello G, Roncarolo D, Amato S, van Ree R. String bean-induced anaphylaxis. Allergy 2001;56(3):259-60

[ 36 / 51 ]

A 5-year-old boy with a history of urticaria pigmentosa and asthma developed severe colic and itching of his urticaria pigmentosa lesions 12 h after eating bread with chocolate spread. These symptoms resolved spontaneously about 1 h later. 2 years before, his parents had noticed urticaria around his mouth after he had eaten hazelnut containing chocolate spread. Subsequently,hazelnut-containing food products had been eliminated from his diet. Monosensitization to
hazelnut (SPT 3+ and CAP 1.79 kU/l) was shown. In view of the history
of urticaria pigmentosa, it would not have been ethical to challenge this patient. Contamination of the chocolate spread with hazelnut was
considered. The presence of hazelnut was shown in all the samples. (Wensing 2001 ref.7164 3)

Wensing M, Koppelman SJ, Penninks AH, Bruijnzeel-Koomen CA, Knulst AC. Hidden hazelnut is a threat to allergic patients. Allergy 2001;56(2):191-2

[ 37 / 51 ]

This study investigated the cross-reactivity to non-Rosaceae LTPs. IgE antibodies to Rosaceae LTPs reacted to a broad range of vegetable foods were evaluated in 498 subjects (age > 12 years) with Rosaccae allergy as judged by skin prick test with fresh fruits and (in most cases) clinical history. The majority had OAS (>97%), and only a minority (approximately 10%) showed urticaria/angioedema, gastrointestinal symptoms, food-induced rhinitis, asthma, or anaphylaxis. Sera from 37 patients were available for follow-up studies. Peach was identified most frequently as an offending Rosaceae food (in 30/37 patients), followed by apple (16/37), apricot (11/37), cherry (9/37), plum (8/37), almond (7/37) and pear (6/37). Four patients did not have any clinical symptoms related to Rosaccae fruits, despite a positive SPT with commercial plum extract and peach peel extract. All 37 patients were interviewed for allergies to other foods. Walnut and hazelnut were most frequently reported as offending foods (19/37 and 15/37, respectively), closely followed by peanut (9/37). For the other 33 different foods, the number of patients reporting symptoms ranged from 1 to 5. These foods were found among all major groups of vegetable foods, including cereals (corn, wheat), legumes (soybean, string bean, white bean, chick pea, lentils, lupine), Solanaceae (potato, tomato, eggplant) Brassicaceae (cabbage, mustard), Umbelliferae (celery, fennel), Rutaceae (lemon, orange), and several other plant families. This article contains a table of the 37 patients and the effecting foods and symptoms of each patient.
(Asero 2000 ref.3711 7)

Asero R, Mistrello G, Roncarolo D, de Vries SC, Gautier MF, Ciurana CL, Verbeek E, Mohammadi T, Knul-Brettlova V, Akkerdaas JH, Bulder I, Aalberse RC, van Ree R. Lipid transfer protein: a pan-allergen in plant-derived foods that is highly resistant to pepsin digestion. Int Arch Allergy Immunol 2000;122(1):20-32

[ 38 / 51 ]

Allergy to hazelnut is most frequently observed in patients with birch pollinosis. This phenomenon can largely be explained by crossreactive IgE against the major birch pollen allergen Bet v 1 and its homologue in hazelnuts Cor a 1. In addition, profilin and carbohydrate structures can be involved. Symptoms of food allergy in these pollinosis patients are usually mild and restricted to the oral cavity. On the other hand, allergy to hazelnuts without concomitant pollinosis is less common, but symptoms tend to be more severe and are often systemic. (Akkerdaas 2000 ref.3541 7)

Akkerdaas J, Hafle S, Aalberse R, van Ree R Characterization of non-pollen-related hazelnut alergens AAAAI 56th Annual Meeting 2000;March 3–8

[ 39 / 51 ]

Allergy to hazelnut is fairly common in Europe. Eighty-six subjects with a history of symptoms after hazelnut ingestion were recruited from 3 allergy centers (Milan, Zurich, and Copenhagen). All subjects underwent skin prick tests (SPTs) with aeroallergens and hazelnut, as well as having their specific hazelnut IgE levels determined. Diagnosis of clinical relevant food allergy was made on the basis of the DBPCFC. Sixty-seven (77.9%) of 86 subjects had a positive DBPCFC result; 8 were placebo responders, and 11 were nonresponders. Of the 11 nonresponders, 4 had positive open-challenge test results. Of the DBPCFC-positive subjects, 87% also had positive skin test responses to birch pollen extract. Food allergy to Hazelnut was the only inclusion criterion, but all patients recruited had a Birch pollen-related food allergy and developed almost exclusively oral allergy syndrome (OAS) during the challenge. (Ortolani 2000 ref.7877 1)

Ortolani C, Ballmer-Weber BK, Hansen KS, Ispano M, Wüthrich B, Bindslev-Jensen C, Ansaloni R, Vannucci L, Pravettoni V, Scibilia J, Poulsen LK, Pastorello EA. Hazelnut allergy: a double-blind, placebo-controlled food challenge multicenter study. J Allergy Clin Immunol 2000;105(3):577-81

[ 40 / 51 ]

Usually hazelnut allergic patients suffer from the tree pollen associated oral allergy syndrome caused by cross-reactive structures. In this German study that assessed the IgE reactivity of a young woman with severe allergic reactions after ingestion of hazelnuts without any association to tree pollen allergy, a further group of 53 patients allergic to Hazelnuts with Birch pollen allergy were recruited, the majority were sensitized to the pollen-related Hazelnut allergen Cor a 1.04 and that only the one serum sample from the patient without pollinosis reacted to non pollen-associated hazelnut allergens. This young woman with severe allergy to hazelnut but without cross-reactivity to birch pollen is described. Reactivity to proteins of 50, 42, 38, 9 and 7 kDa were recorded. Probably the heat-labile profilin allergen was destroyed, but heat-labile allergens not (particularly stable were those allergens in the 7- and 9-kD range). These allergens were not reactive with serum IgE from multiple patients with histories of birch pollinosis. Possible allergens in this size range include LTPs and 2S albumins. In summary, proteins with MWs ranging from 12 to 100 kDa were detected as allergenic structures by the 53 sera. Of the "birch pollen related food allergy" (BPRF) patients 75 % identified IgE reactivity to an 18 kDa component, which appears to be the major hazelnut allergen. This allergen could be recognized as the Bet v 1-analogous structure in hazelnuts. Of these patients 19% showed IgE reactivity to a 14 kDa protein, identified as profilin. Further allergens were detected at 20,23,31,50, 55 and 62 kDa. Moreover, a broad spectrum of IgE reactivities was identified above 30 kDa which were identified as glycoproteins with cross-reactive carbohydrate determinants (CCD). However, the binding pattern of the 53 sera differed individually. (Schocker 2000 ref.7875 7)

Schocker F, Luttkopf D, Muller U, Thomas P, Vieths S, Becker WM. IgE binding to unique hazelnut allergens: identification of non pollen-related and heat-stable hazelnut allergens eliciting severe allergic reactions. Eur J Nutr 2000;39(4):172-80

[ 41 / 51 ]

The probability of a patient with nut allergy having specific IgE to a particular combination of peanut, hazelnut and brazil nut is similar, whatever their age or sex. The apparent increase in multiple nut reactivity with increasing age may therefore be due to exposure of previously unchallenged sensitivity. The frequency of multiple-nut specificity is sufficiently high that patients should always be tested for allergy to a range on nuts if they have a history of reacting to any nut. (Pumphrey 1999 ref.7807 4)

Pumphrey RS, Wilson PB, Faragher EB, Edwards SR. Specific immunoglobulin E to peanut, hazelnut and brazil nut in 731 patients: similar patterns found at all ages. Clin Exp Allergy 1999;29(9):1256-9

[ 42 / 51 ]

Of a total of 196 birch pollen-hypersensitive patients with oral allergy syndrome (OAS), 195 had apple and/or hazelnut allergy, and 103 had Apiaceae sensitivity; only one patient had Apiaceae (carrot, celery, and fennel) allergy alone. (Asero 1997 ref.1714 4)

Asero R. Relevance of pollen-specific IgE levels to the development of Apiaceae hypersensitivity in patients with birch pollen allergy. Allergy 1997;52(5):560-4

[ 43 / 51 ]

Nut oils may pose a threat to patients with allergy, depending on the method of manufacture and processing. (Teuber 1997 ref.1631 8) Hazelnut or other nut oils may be used in chocolate manufacturing. If not completely cleared of hazelnut allergens, may cause an allergy reaction.

Teuber SS, Brown RL, Haapanen LA. Allergenicity of gourmet nut oils processed by different methods. J Allergy Clin Immunol 1997;99(4):502-7

[ 44 / 51 ]

A series of 202 labial food challenges (LFC) performed over two years in 142 children with food allergy suspected from the case history, positive skin prick tests and specific serum IgE assays: 156 LFC were positive; and 46 negative, followed by positive single-blind, placebo-controlled food challenges (SBPCFC). The foods provoking reactions were egg white (75 cases), peanut (60 cases), mustard (23 cases), cow's milk (13 cases), cod (8 cases), kiwi fruit, shrimp (4 cases each), chicken, peanut oil (3 cases each), hazel nuts (2 cases), and snails, apple, fennel, garlic, chilli peppers, pepper, and duck (1 case each). LFC positivity was mostly (89.7% of cases) manifested as a labial edema with contiguous urticaria. There were systemic reactions in 4.5% of cases: generalized urticaria, hoarseness and rapid-onset and generalized eczema. The 46 infants with negative LFC results had positive SBPCFC. The reactions were in 34 cases generalized urticaria, 10 cases asthma attacks, 2 cases early and generalized eczema, and in one case general anaphylactic shock. The sensitivity of the LFC was 77%. The LFC was easy to perform with children. Positive results indicate the presence of food allergy, but negative results require further investigations preferably double-blind, placebo-controlled food challenge (DBPCFC).

Rance F, Dutau G. Labial food challenge in children with food allergy. Pediatr Allergy Immunol 1997;8(1):41-44

[ 45 / 51 ]

In a study of 62 patients with nut allergy (adults and children), peanuts were the commonest cause of allergy (47) followed by Brazil nut (18), almond (14), and hazelnut (13). The commonest symptom was facial angioedema, and the major life threatening reaction was laryngeal oedema. Hypotension was uncommon. (Ewan 1996 ref.1625 8)

Ewan PW. Clinical study of peanut and nut allergy in 62 consecutive patients: new features and associations. BMJ 1996;312(7038):1074-8

[ 46 / 51 ]

The prevalence in the Netherlands of atopy caused by apple, peach, and hazelnut in patients with tree pollinosis was evaluated. Skin prick tests for apple, peach, and hazelnut were positive in 51 (64.6%), 61 (77.2%), and 71 (89.9%) patients, respectively. Granny Smith showed more positive skin reactions and a better agreement with clinical history than Golden Delicious. RAST for apple, peach, and hazelnut was positive in 53 (68.8%), 13 (16.9%), and 31 (40.3%) patients, respectively. (de Groot 1996 ref.1411 8)

de Groot H, de Jong NW, et al. Birch pollinosis and atopy caused by apple, peach, and hazelnut; comparison of three extraction procedures with two apple strains. Allergy 1996;51(10):712-8

[ 47 / 51 ]

A fragment fo hazelnut in a teaspoon of muesli caused severe laryngeal edema. (Ewan 1996 ref.1625 5) One piece of chocolate (3-6 g) containing 0.2% of undeclared hazelnut caused asthma in an allergic individual. Severe reactions have also been reported after ingestion of meat products that contain casein used, for example, as a texturing agent at concentrations ranging from 1.1% to 0.04%.
Fatal anaphylactic reaction after ingestion of a hamburger containing undeclared soybean additives (2.1% soybean protein). Two additional allergic reactions occurred after ingestion of a kebab containing 7% soybean protein and crab sticks containing 0.5–0.9% undeclared soybean protein. (Malmheden 1994 ref.8868 0)

Malmheden Yman I, Eriksson A, Everitt G, Yman L, Karlsson T. Analysis of food proteins for verification of contamination or mislabelling. Food Agric Immunol 1994;6:167-172

[ 48 / 51 ]

Food-dependant exercise-induced anaphylaxis. (Martin Munoz 1994 ref.1201 1)

Martin Munoz F, Compaird JA, et al. Exercise-induced anaphylaxic reaction to hazelnut Allergy 1994;49:314-316

[ 49 / 51 ]

Sensitivity to nuts is more pronounced in patients during and after the tree pollen season; in this respect pollen allergens may boost production of IgE antibodies, and when surpassed, an individual threshold of latent nut intolerance frequently gets manifest. (Hirschwehr 1992 ref.4840 0)

Hirschwehr R, Valenta R, Ebner C, Ferreira F, Sperr WR, Valent P, Rohac M, Rumpold H, Scheiner O, Kraft D. Identification of common allergenic structures in hazel pollen and hazelnuts: a possible explanation for sensitivity to hazelnuts in patients allergic to tree pollen. J Allergy Clin Immunol 1992;90(6 Pt 1):927-36

[ 50 / 51 ]

In this study, 102 patients with the initial diagnosis of idiopathic anaphylaxis were evaluated with a battery of 79 food-antigen skin prick tests selected to include foods reported or suspected of provoking anaphylaxis. Thirty-two patients (31%) had positive tests to one or more food antigens. In five of these patients, subsequently eating a food that elicited a positive test provoked an anaphylactic reaction. Two patients eliminated the foods completely, stopped having reactions, and refused challenge. In these seven patients, 10 different antigens provoked anaphylaxis: aniseed, cashew nut, celery, flaxseed, hops, mustard, mushroom, shrimp, sunflower, and walnut. We conclude that a battery of selected food-antigen skin prick tests provided a useful method for identifying an offending antigen in these patients and that some (7% in our series) cases of "idiopathic" anaphylaxis by history are not truly idiopathic.
The 10 antigens with positive clinical correlation
Antigens A B C
Aniseed 1 5 20
Cashew nut 1 2 50
Celery 2 4 50
Flaxseed 1 1 100
Hops 1 2 50
Mushroom 1 3 33
Mustard 2 3 66
Shrimp 1 3 33
Sunflower seed 1 3 33
Walnut 1 1 100
A = Total No. of positive skin tests with positive correlation
B = Total No. of positive skin tests
C = Percent of positive skin tests with positive correlation

Total number of positive skin prick tests.
2 - Almond
5 - Aniseed
1 - Artichoke
1 - Baker's yeast
1 - Beet
1 - Brazil nut
2 - Brewer's yeast
1 - Caraway seed
2 - Cashew nut
5 - Castor bean
4 - Celery
8 - Chamomile
2 - Chestnut
1 - Chicory
1 - Clam
2 - Coconut
1 - Cottonseed
2 - Crab
1 - Fennel
4 - Filbert (hazelnut)
I - Flaxseed
1 - Garbanzo bean
2 - Ginger
1 - Halibut
1 - Honey
2 - Hops
3 - Horseradish
1 - Lentil
1 - Lima beans
2 - Lobster
2 - Mango
1 - Milk
5 - Millet
3 - Mushroom
3 - Mustard
1 - Nutmeg
2 - Pea
1 - Pistachio
3 - Poppy seed
2 - Sesame seed
3 - Shrimp
3 - Sunflower
1 - Thyme
1 - Tumeric
1 - Walnut
None for Allspice, Apple, Banana, Bay leaf, Black pepper, Buckwheat, Cantaloupe, Chicken, Chili pepper, Chocolate, Cinnamon, Clove, Cod, Corn, Cumin seed, Dill seed, Egg, Garlic, Juniper berry, Orange, Oyster, Peach, Peanut, Potato, Psyllium seed, Raspberry, Sage, Salmon, Soybean, Strawberry, Sweet potato, Tangerine, Tapioca, Vanilla.
7 patients with positive clinical correlation to a SPT
1 : Aniseed
2 : Shrimp
3 : Mustard, flaxseed
4 : Celery, hops
5 : Celery, mustard, sunflower
6 : Walnut, cashew nut
7 : Mushroom
(Stricker 1986 ref.9 3606)

Stricker WE, Anorve Lopez E, Reed CE. Food skin testing in patients with "idiopathic anaphylaxis". J Allergy Clin Immunol 1986;77:516-519

[ 51 / 51 ]

24% of 276 adult patients reported asthma or rhinitis symptoms on eating or handling various foods, of which hazelnut, apple and shell fish were the most often named. (Eriksson 1978 ref.1247 5)

Eriksson NE. Food sensitivity reported by patients with asthma and hay fever. Allergy 1978;33:189-196

Non-Immune reactions

[ 1 ]

An 18-month-old boy choked on a fragment of a hazelnut shell. (Reiser 2012 ref.28936 0)

Reiser J, Gehl A, Hermann V, Püschel K. Suffocation due to foreign body aspiration visualized by post-mortem CT. [German] Arch Kriminol 2012 Jan-Feb;229(1-2):55-61.

[ 2 ]

In this study, cacao, banana, egg and hazelnuts were found to be responsible for migraine headaches in children and young adults. On an oligoantigenic diet, 6/12 presented a completed remission of headache, and 5/12 had a significant improvement of the migrainous pattern. (Guariso 1993 ref.2092 3)

Reorganization process. Data in process of being reorganized. Editorial staff 2006

[ 3 ]

Migraine. In this study, cacao, banana, egg and hazelnuts were found to be responsible for migraine headaches in children and young adults. On an oligoantigenic diet, 6/12 presented a completed remission of headache, 5/12 had a significant improvement of the migrainous pattern (Guariso 1993 ref.2092 7)

Guariso G, Bertoli S, Cernetti R, Battistella PA, Setari M, Zacchello F. Migraine and food intolerance: a controlled study in pediatric patients [Italian] Pediatr Med Chir 1993;15(1):57-61

[ 4 ]

The effects on iron absorption of nuts were measured in 137 Indian women. When the absorption from bread and nut meals (walnuts, almonds, peanuts, and hazelnuts) was compared with that from bread meals, the overall geometric mean absorption from the nut meals (1.8%) was significantly less than from the bread meals alone (6.6%). In contrast, coconut did not reduce absorption significantly. All the nuts tested contained significant amounts of two known inhibitors of iron absorption (phytates and polyphenols) but the amounts in coconut were significantly less than in the other nuts. Fifty milligrams ascorbic acid overcame the inhibitory effects of two nuts that were tested (Brazil nuts and peanuts). This is different from that found previously for soy protein, another potent inhibitor of iron absorption. (Macfarlane 1988 ref.7810 1)

Macfarlane BJ, Bezwoda WR, Bothwell TH, Baynes RD, Bothwell JE, MacPhail AP, Lamparelli RD, Mayet F. Inhibitory effect of nuts on iron absorption. Am J Clin Nutr 1988;47(2):270-4

Occupational reactions

[ 1 ]

This study evaluated the association between the hazelnut sensitization and workplace-related respiratory complaints in hazelnut processing workers. 88 hazelnut processing workers (79 females and 9 males), aged 14-59 years were investigated. The mean working duration was 38.8 ± 36.6 months (min: 1-max: 180). Specific IgE against hazelnut allergens was positive in 14 of cases (17.1%). There was no significant difference between the cases with and without specific IgE against hazelnut allergens regarding respiratory symptoms, history of allergy, smoking status and spirometric values. (Balbay 2012 ref.28927 7)

Balbay EG, Karatas N, Arbak P, Binay S, Yavuz O, Annakkaya AN, Balbay O, Toru U. Serum IgE antibodies against hazelnut in hazelnut processing workers. ScientificWorldJournal 2012;2012:108953.

[ 2 ]

This study showed that occupational exposure to hazelnut caused skin sensitivity to hazel and birch pollen, but this was not associated with an enhanced risk for allergic diseases. (Suna 2005 ref.12338 7)

Reorganization process. Data in process of being reorganized. Editorial staff 2006 <

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