Prevalence data are based on different diagnostic procedures. While the prevalence of sensitization (sensitivity) can be estimated by SPT, RAST, and immunoblot, a clinical relevant sensitization (allergy) is evaluated by convincing history (anamnesis) or food challenge tests (ideally by DBPCFC).
1.1 General Population
Prevalences within the author's selected populations are
listed. Those that are assigned randomly selected ("unselected") with numbers
more than 500 may be regarded as representative of the "general population".
Inclusion criteria may involve circumstances not related to atopic predisposition
according to current knowledge.
| Country / Subjects | Allergy / Sensitivity | References |
| Australia, Victoria
a) 332 unselected new-born infants b) 4078 children with suspected peanut or tree nut allergy (age < 14 years) (study 1990-96) c) 620 children at risk of atopy (followed from birth for 2 years) |
hazelnut 0.18%
(frequency of almond allergy in b), corrected for prevalence ratio to peanut allergy in b) and c), extrapolated by risk of atopy in a) |
Hill et al. 1997 |
| UK
16420 randomly selected adults (age of >15 years) |
tree nuts 0.4% (interview survey, questionnaire) | Emmett et al. 1999 |
| UK, Isle of White
1218 children of general population |
tree nuts 0.7%
hazelnut 0.1% (SPT, Clinical history) |
Tariq et al. 1996 |
| USA
a) adults and b) children of general population |
peanut and/or tree nuts
a) 1.6% b) 0.6% (telephone survey, estimated corrected prevalence: 1.1% in general population) |
Sicherer et al. 1999 |
1.2 Subjects with Atopic or Other Diseases
| Country / Subjects | Allergy / Sensitivity | References |
| Croatia, Zagreb
71 confectionary workers |
hazelnut 6% (SPT) | Zuskin et al. 1994 |
| Denmark, Copenhagen
101 birch pollen and/or hazelnut sensitive patients |
hazelnut 72% (SPT) | Andersen & Lowenstein 1978 |
| France
20 latex allergic or at risk patients |
hazelnut 15% (RAST) | Leonard et al. 1996 |
| France
80 cases of food- related anaphylaxis (study period 1993-97) |
hazelnut, cashew nut, pistachio 7.5% (reported to CICBAA databank) | European Commission 1998 |
| France, Nancy and Toulouse
544 food allergic children |
hazelnut 2.7% (food challenge) | Rance et al. 1999 |
| France, Paris
19 patients with exercise-induced anaphylaxis |
tree nuts 32% (SPT, RAST) | Guinnepain et al. 1996 |
| France, Pierre Benite
580 patients with adverse reactions to food |
hazelnut 22% (RAST) | Andre et al. 1994 |
| France, Toulouse
142 food allergic children |
hazelnut 1.4 % (labial food challenge) | Rance & Dutau 1997 |
| Germany, Berlin
167 pollen and food sensitive patients |
hazelnut 90% and 78%
(SPT and case history) |
Jankiewicz et al. 1996 |
| Germany, Cologne
225 hazel pollen allergic patients |
hazelnut 92% (scratch test) | Herkenrath et al. 1982 |
| Germany, Ulm
80 patients with pollen associated food allergy |
hazelnut 71% (clinical history, SPT) | Boehncke et al. 1998 |
| Italy, Florence
54 episodes of food-dependent anaphylaxis in 44 children (age of 1 month to 16 years) (from 1994-1996) |
hazelnut 1.9% | Novembre et al. 1998 |
| Italy, Genoa
132 pollen and food sensitive patients |
hazelnut 22%
(incidents of hypersensitivity) |
Troise et al. 1992 |
| Italy, Milan
262 fruit and/or vegetable allergic patients |
hazelnut 37 % (clinical history) | Ortolani et al. 1988 |
| Italy, Milan
100 fruit and/or vegetable allergic patients |
hazelnut 32 % (clinical history) | Ortolani et al. 1989 |
| Netherlands
131 cases of food- induced anaphylaxis (from 1993-1997) |
tree nuts 18% (survey, reported to the TNO Nutrition and Food Research Institute) | European Commission 1998 |
| Netherlands, Rotterdam
79 tree-pollen allergic patients |
hazelnut 90%, 40%, and 44%
(SPT, RAST, and case history) |
de Groot et al. 1996 |
| Poland
163 food allergic infants |
hazelnut 42% (RAST) | Hofman 1994 |
| Spain, Barcelona
102 patients allergic to dried fruits |
hazelnut 76%, 58%, and 69%
(SPT, HR, and RAST) |
Amat Par et al. 1990 |
| Spain, Madrid
355 food allergic children |
hazelnut 5.4% (SPT, RAST) | Crespo et al. 1995 |
| Spain, Madrid
29 plant-derived food allergic patients |
hazelnut 10% (SPT) | Diez-Gomez et al. 1999 |
| Spain, Pamplona
74 patients with atopic dermatitis |
nuts 6.8%(SPT, RAST, Histamine Release) | Resano et al. 1998 |
| Spain, Salamanca
a) 84 mugwort sensitive patients without other pollen sensitizations b) 57 fruit allergic patients (age of 6-56 years, mean 21.5) |
a) hazelnut 2.4% (RAST)
b) hazelnut 8.8%(clinical history) |
a) Garcia-Ortiz et al. 1996
b) Garcia Ortiz et al. 1998 |
| Sweden
60 severe allergic reactions caused by food |
soybean, nuts and almonds >70% | Foucard et al. 1997 |
| Sweden
a) 61 cases of food- induced anaphylaxis (from 1994-1996) b) 55 cases of food- induced anaphylaxis (from 1994-1996) |
a) tree nuts 18% (reported
to the National Food Administration)
b) tree nuts 16%(Hospital Reports) |
European Commission 1998 |
| Sweden, Halmstad / Malmö
a) 380 birch pollen allergic patients b) 103 patients without birch pollen allergy |
a) hazelnut 53%
b) hazelnut 7% (questionaire) |
Eriksson et al. 1982 |
| Sweden, Skövde
47 birch pollen allergic patients |
nuts and apples 68% (Clinical history) | Fogle-Hansson & Bende 1993 |
| Switzerland, Bern
22 patients with severe food-induced anaphylaxis (study period 1994-96) |
nuts 14% | Rohrer et al. 1998 |
| Switzerland, Zurich
a) 402 food allergic adults (study period 1978-87) b) 383 food allergic patients (study period 1990-94) |
a) hazelnut 2.5%
b) hazelnut 37% (anamnesis, clinical relevance, diagnostic tests) |
a) Wüthrich 1993
b) Etesamifar & Wüthrich 1998 |
| UK, Cambridge
62 peanut and/or nut allergic patients |
hazelnut 21% (SPT) | Ewan 1996 |
| UK, London
100 patients with food intolerance |
nuts/peanuts 22% (repeated challenge) | Lessof et al. 1980 |
| UK, Manchester
90 patients expierenced anaphylactic reactions to foods (from 1994-1996) |
hazelnut 4.4% (suspected cause of patients' worst reaction) | Pumphrey & Stanworth 1996 |
| USA, Denver, CO
a) 180 food allergic children b) 32 peanut allergic children |
a) nuts 10% (DBPCFC)
b) nuts 0% (DBPCFC) |
Bock & Atkins 1990 |
| USA, Little Rock, AR
54 tree nut allergic patients |
hazelnut 13% (acute allergic reactions) | Sicherer et al. 1998 |
1.3 Associated Allergies
| Country / Subjects | Allergy / Sensitivity | References |
| Multicenter (Copenhagen,
Milan, Zurich)
67 patients with positive DBPCFC to hazelnut |
birch pollen 87% (SPT) | Ortolani et al. 2000 |
| Switzerland, Zurich
19 patients with positive DBPCFC to hazelnut |
hazel pollen 100%
birch pollen 100% alder pollen 100% ash pollen 68% grass pollen 53% rye pollen 53% mugwort pollen 16% (SPT) |
Ballmer-Weber et al. 2000 |
2 Symptoms of Hazelnut Allergy
| Symptoms & Case Reports | References |
| systemic reactions
anaphylaxis (3, 5, 11, 13), exercise-induced anaphylaxis (8, 10) cutaneous symptoms
gastrointestinal symptoms
respiratory symptoms
other symptoms
|
(1) Aas 1978
(2) Ortolani et al. 1989 (3) Gluck 1990 (4) Hirschwehr et al. 1992 (5) Fogle-Hansson & Bende 1993 (6) Guariso et al. 1993 (7) Vocks et al. 1993 (8) Martin-Munoz et al. 1994 (9) Ewan 1996 (10) Guinnepain et al. 1996 (11) Pumphrey & Stanworth 1996 (12) Asero 1997 (13) Diez-Gomez et al. 1999 |
| Onset of Symptoms
Symptoms occurred immediately or within a few minutes in all patients after ingestion of hazelnut, 1 patient had additional reactions of conjunctivitis and rhinitis after 4 hours (67 DBPCFC positive patients) |
(1) Ortolani et al. 2000 |
| Percentage of reactions
Asthma 65%, atopic dermatits 80%, allergic rhinitis 55%, and food hypersensitivity 90% in 20 tree nut allergic patients without peanut allergy (1) Symptoms of first acute allergic reactions to tree nuts in 54 patients: skin only 28%, respiratory only 11%, gastrointestinal only 3%, skin and respiratory 31%, skin and gastrointestinal 5%, gastrointestinal and respiratory 1%, all 3 systems 21% (1) Symptoms after DBPCFC with hazelnut in 67 patients: oral allergy syndrome in 88%, oral and gastrointestinal symptoms in 4.5%, and oral and systemic symptoms in 7.5% (2) |
(1) Sicherer et al. 1998
(2) Ortolani et al. 2000 |
| Threshold for Elicitation of Symptoms
A dose of 500 mg filbert (Corylus maxima) induced symptoms of asthma, conjunctivitis, and urticaria in a hazelnut allergic patient (DBPCFC) (1) The mean provocative doses were 1.4 g, 2.7 g, and 15.3 g hazelnut in hazelnut allergic patients from Copenhagen, Zurich, and Milan, respectively (DBPCFC) (2) |
(1) Bock 1978
(2) Ortolani et al. 2000 |
3 Diagnostic Features of Hazelnut Allergy
| Parameters / Subjects | Outcome | References |
| Age and Onset of Symptoms
54 tree nut allergic patients |
Age of patients at first reactions:
62 months (10 to 264 months) Time of onset after ingestion: 2 min (0.3 to 30 min) (median / range) |
Sicherer et al. 1998 |
| Age and Gender
731 tree nut allergic patients (age 7 months to 65 years, median 6.6 years) |
Similar sensitization pattern to peanut, hazelnut, and brazil nut at all ages and gender (RAST) | Pumphrey et al. 1999 |
| IgE
patients who believed they never ingested tree nuts |
Hazelnut specific serum IgE (RAST):
2.7 kIU/L (median) |
Sicherer et al. 1998 |
| IgE
birch pollen allergic patients: a) responding and b) non-responding to DBPCFC with birch pollen related foods |
Hazelnut specific serum IgE (RAST):
a) 17.4 kU/L b) 8.6 kU/L (mean values, no significant difference) |
Reekers et al. 1999 |
| SPT, IgE and Clinical Relevance
nut allergic patients |
SPT and RAST were found to be reliable for the diagnosis of allergy to nuts | Aas 1978 |
| SPT, IgE and Clinical Relevance
43 to 67 hazelnut allergic patients |
positive reactions in 51% and 12% of patients with clinical
hazelnut allergy tested with fresh hazelnuts and commercial extracts, respectively
(SPT)
hazelnut specific IgE in 55% of patients with clinical hazelnut allergy (RAST) |
Ortolani et al. 1988 |
| a) RAST and Clinical Relevance
b) SPT and Clinical Relevance 27 patients with clinical history of hazelnut allergy |
a) RAST (specific IgE > 0.7 kU/L):
positive results in 48% positive preditive value 72% negative preditive value 52% b) SPT with commercial extracts and fresh food: positive results in 22% and 41% positive preditive value 66% and 73% negative preditive value 45% and 51% |
Ortolani et al. 1989 |
| RAST and Clinical Relevance
46 patients with clinical history and positive SPT to hazelnut |
Hazelnut specific RAST:
positive 87% negative 13% |
Boehncke et al. 1998 |
| SPT, RAST, Histamine Release and Clinical
Relevance
102 patients allergic to dried fruits |
Correlation of tests to clinical history of hazelnut
allergy:
87% for SPT 80% for HR 89% for RAST |
Amat Par et al. 1990 |
| SPT, RAST and Histamine Release
30 birch pollen allergic patients with clinical symptoms of hazelnut allergy |
Positive results to hazelnut in:
50% by SPT 43% by RAST 80% by Histamine Release |
Bindslev-Jensen et al. 1991 |
| RAST and Open Challenge
children considered on history to be allergic to tree nuts |
Children with positive IgE tree nut titres:
>50% negative challenge test |
Armstrong & Rylance 1999 |
| SPT, RAST, and DBPCFC
86 patients with history of hazelnut allergy (from Copenhagen, Milan, Zurich) |
Positivity in DBPCFC: 78% (8 placebo
responders; 11 non-responders of which 4 had positive open- challenge)
Tests in DBPCFC-positive subjects: a) RAST (specific IgE > 0.7 kU/L): positive preditive value 92% negative preditive value 5% b) SPT with commercial extracts and fresh food: positive preditive value 92% and 94% negative preditive value 5% and 15% |
Ortolani et al. 2000 |
| Open Challenge
17 children with perceived peanut or tree nut allergy |
Open challenge procedure, where negative tests (SPT, RAST) indicate tolerance of nuts: 15 showed no reactions, all of them continued to ingest foods containing nuts without incidents. | Baker et al. 1999 |
| HLA Genotypes
Birch pollen and hazelnut allergic patients |
HLA-alleles DRB1*01, DQA1*0101, and DQB1*0501 were significantly decreased as compared to pollen allergic patients in general; insignificant differences as compared to birch pollen allergic individuals without hazelnut allergy | Boehncke et al. 1998 |
| Birch Pollen spec. IgE
103 birch pollen- hypersensitive patients free of oral allergy syndrome (at begin of the followed-up study) |
Birch pollen specific serum IgE- levels in patients:
a) who developed Apiaceae (carrot, celery, fennel) sensitivity 15.5 AU/mL b) who developed apple/hazelnut allergy only 8.5 AU/mL c) who remained free of oral allergy syndrome 5 AU/mL (median values, P < 0.05) |
Asero 1997 |
| Birch Pollen spec. IgE
19 patients with positive DBPCFC to hazelnut |
All patients had Bet v 1-specific IgE and 5 patients had Bet v 2-specific IgE (RAST) | Ballmer-Weber et al. 2000 |
| Treatment* | Outcome | References | ||||||||||||||||||||
| Treatment with Astemizole
30 birch pollen allergic patients with clinical symptoms of hazelnut allergy |
Treatment with astemizole significantly reduced the symptoms after oral provocation with hazelnuts compared with placebo (P = 0.004) without completely abolishing symptoms | Bindslev-Jensen et al. 1991 | ||||||||||||||||||||
| Tree Pollen Immunotherapy
72 children with birch pollinosis (age of 6-16 years), prevalence of adverse reactions to nuts before immunotherapy 79% I. subcutaneous immunotherapy for 3 years with a) birch pollen preparation or b) a mixture of birch, alder, and hazel pollen II. oral immunotherapy for 10 months with c) birch pollen preparation or d) placebo capsules |
Assessment of food allergy after treatment (self-reported):
|
Möller 1989 |
6 Allergens of Hazelnut and Pollen
| Nut Proteins / Glycoproteins | Allergen Nomenclature | References |
| Major Hazelnut Allergen [18 kDa] | Cor a 1.0401 | Hirschwehr et al. 1992, Lüttkopf et al. 1999 [GenBank] |
| Hazelnut Profilin | van Ree et al. 1992, 1995 | |
| Lipid-transfer protein [9 kDa] | Akkerdaas et al. 2000 | |
| Allergens: 14, 18, 37, 40, 46, and 69 kDa | Hirschwehr et al. 1992 | |
| Allergens: 2 allergens <16 kD, 17 kDa, and 42 kDa | Caballero et al. 1997 | |
| Allergens: 7, 9, 38, 42, and 50 kDa | Schocker et al. 1999 | |
| Allergens: 25, 37, and 55 kDa, and 14, 18, 22, and 69 kDa | Koppelman et al. 1999 | |
| 4.8 kDa Allergen | Hird et al. 2000 |
| Pollen Proteins / Glycoproteins | Allergen Nomenclature | References |
| Major Pollen Allergen [17 kDa] | Cor a 1 | Rohac et al. 1991, Breiteneder et al. 1993, Hoffmann-Sommergruber et al. 1997 |
| Allergens: 14, 17, 37, 44, 60, and 69 kDa | Hirschwehr et al. 1992 |
6.1 Sensitization to Hazelnut Allergens
| Country / Subjects | Sensitivity to | References | |||||||||||||||||||||||||||||||||||||||||||||
| Austria, Vienna
a) 25 hazel pollen and hazelnut allergic patients b) 18 hazel pollen allergic patients without sensitivity to hazelnuts |
Hazel pollen:
Hazelnut:
|
Hirschwehr et al. 1992 | |||||||||||||||||||||||||||||||||||||||||||||
| Germany, Berlin / Borstel / Langen
a) 27 hazelnut allergic patients b) 28 hazelnut and birch pollen sensitive children |
Hazelnut:
|
Müller et al. 2000 | |||||||||||||||||||||||||||||||||||||||||||||
| Germany, Munich
7 hazelnut allergic patients |
Hazelnut:
20 kDa allergen in 71% 14 - 67 kDa allergens (SDS-PAGE / immunoblot) |
Vocks et al. 1993 | |||||||||||||||||||||||||||||||||||||||||||||
| UK, Manchester / York
4 hazelnut-peanut sensitized patients |
Hazelnut:
4.8 kDa allergen (2D-PAGE / immunoblot, MALDI-TOF) |
Hird et al. 2000 |
6.2 Major Hazelnut Allergen (Cor a 1.0401)
6.3 Major Pollen Allergen (Cor a 1)
| Extract / Purified Allergens | Methods | References |
| Protein extract from nuts | Nuts grounded under liquid nitrogen, extraction overnight at 4°C with potassium phosphate buffer (pH 7.0) containing PVPP, EDTA, sodium diethyldithiocarbamate and sodium azide, centrifugation, filtration, dialysis, and lyophylization, storage -20°C | Hirschwehr et al. 1992 |
| Protein extract from nuts | Comparison of different extraction conditions (3 buffer systems, 3 temperatures for 4h): no differences in IgE- binding, maximum yield of soluble proteins with tris/tricine buffer at 45°C | Vieths et al. 1998 |
| Protein extract from nuts | Nuts were peeled, chopped, and ground; extraction with ammonium carbonate buffer (pH 8.0) at 4°C for 4h; filtration, defatted extract centrifued, supernatant dialyzed and lyophylized, storage -20°C | Caballero et al. 1997 |
| Protein extract from nuts | Nuts blended and added to ammonium bicarbonate buffer (pH 7.8), placed on ice, blended and rocked for 48 h at 4°C, centrifugation, storage at -70°C | Teuber et al. 1997 |
| Protein extract from nuts | Hazelnuts were shelled, skinned, and ground; extraction with bicarbonate buffer (pH 9.2) containing tetramethylen sulphone; homogenization and stirring for 1 h at RT; centrifugation and protein precipitation with acetone at -20°C for 30 min; after centrifugation protein solids washed with butanol and dried | Hird et al. 2000 |
| Protein extract from oil | Oil added to ammonium bicarbonate buffer (pH 7.8), rocked for 48 h at 4°C, centrifugation, and aqueous layer ultracentrifuged, storage at -70°C | Teuber et al. 1997 |
| 18-kDa allergen from hazelnut | Hazelnut protein extract treated 3 times with Bioacryl BPA-1000 (precipitation of nucleic acid and major proteins other than 18-kDa allergen), centrifugation, dialysis of supernatant, further purification with IEC and RP-HPLC | Hirschwehr et al. 1992
Schenk et al. 1994 |
| Hazelpollen allergen Cor a 1 | Aqueous extract of hazelpollen followed by preparative RP-HPLC | Ebner et al. 1993 |
| Cross-Reacting Allergens | Subjects / Methods | References |
| Hazelnut (Pollen)
birch pollen * |
Partial identity between birch pollen and hazelnut antigens (CLIE using rabbit anti- birch Ab) | Andersen & Lowenstein 1978 |
| Hazelnut (Pollen)
birch pollen * |
Correlation between birch pollen allergy and hazelnut hypersensitivity (1129 adults with bronchial asthma and/or allergic rhinitis, questionaire) | Eriksson 1978 |
| Hazelnut (Pollen)
alder, hazel, aspen, and bog-myrde pollen * |
Correlation between sensitization to hazelnut and pollen in birch pollen allergic patients (SPT) | Eriksson et al. 1982 |
| Hazelnut (Pollen)
tree (elm, olive, birch, plane, ash), weed (parietaria, mugwort), and grass pollen * |
Sensitization to pollens in 63 hazelnut allergic patients: tree pollen 67%, weeds 40%, grasses 11% (2 positive results from SPT, HR, and RAST) | Amat Par et al. 1990 |
| Hazel pollen (Pollen)
birch pollen, Cor a 1 |
Inhibition of IgE- binding to Cor a 1 by birch pollen extract | Rohac et al. 1991 |
| Hazelnut, Hazel pollen
(Pollen)
birch pollen allergens: a) rBet v 1 b) rBet v 2 (profilin) |
3 patients with hazel pollen and hazelnut allergy (pooled
serum):
a) IgE- binding to 18 kDa hazelnut allergen and Cor a 1 was abolished by rBet v 1 b) IgE- binding to 14 kDa hazelnut and hazel pollen allergens was abolished by rBet v 2 (immunoblot inhibition) |
Hirschwehr et al. 1992 |
| Hazel pollen (Pollen)
birch pollen allergens: rBet v 1 and rBet v 2 (profilin) |
102 patients from Austria, France, Sweden, and Switzerland:
75 to 84% inhibition of IgE- binding to hazel pollen extract by a combination
of recombinant Bet v 1 and Bet v 2 (mean percentages, RAST inhibition)
11 tree pollen allergic patients: inhibition of IgE- binding to 2 hazel pollen allergens of 12 to 17 kDa by Bet v 1 and Bet v 2 (immunoblot inhibition) |
Niederberger et al. 1998 |
| Hazelnut (Pollen)
mugwort pollen |
Serum pool from 28 patients with specific IgE to mugwort
pollen and hazelnut:
63% inhibition of IgE- binding to hazelnut by mugwort; 36% inhibition of IgE- binding to mugwort by hazelnut (RAST inhibition) |
Caballero et al. 1997 |
| Hazelnut
(Pollen)
mugwort pollen allergens (33-, 65-kDa), hazelnut allergens (17-, 42-, <16-kDa) |
Hazelnut extract inhibits IgE- binding to 33- and 65-kDa mugwort allergens; mugwort extract inhibits IgE- binding to all hazelnut allergens (SDS-PAGE and IEF-PAGE immunoblot inhibition) | Caballero et al. 1997 |
| Hazelnut (Pollen)
hazel pollen |
5 patients with hazel pollen and hazelnut allergy (pooled
serum):
IgE- binding to hazelnut allergens was reduced by hazel pollen extract; IgE- binding to hazel pollen allergens was not reduced by hazelnut extract (immunoblot inhibition) |
Hirschwehr et al. 1992 |
| Hazelnut: (Pollen)
birch pollen, rBet v 1, rBet v 2 profilin, timothy grass pollen extract; 21 patients with clinical relevant allergy to pollen and plant-derived food |
Mixture of rBet v 1 and rBet v
2 inhibited IgE-binding to 10-14 kDa (profilin related) and 17-21 kDa (Bet
v 1 related) hazelnut allergens, timothy grass pollen inhibited IgE-binding
to 30-100 kDa allergens from hazelnut (immunoblot inhibition);
83% (4-100%) inhibition of IgE-binding to hazelnut extract by mixture of rBet v 1 and rBet v 2 and 94% (17-100%) by mixture of rBet v1, rBet v 2, and timothy pollen extract (26 sera) (RAST inhibition) |
Kazemi-Shirazi et al. 2000 |
| Hazelnut (Nuts)
walnut, cashewnut, pecannut, almond |
6 hazelnut allergic adults: Inhibition of IgE binding to hazelnut proteins by walnut (30-35%), cashewnut and pecannut (appr. 15%), and almond (appr. 8%) (RAST inhibition) | Koppelman et al. 1999 |
| Hazelnut (Nuts, Peanuts)
significant associations: peanut, walnut, almond * |
262 fruit and/or vegetable allergic patients
(clinical history, SPT, RAST) |
Ortolani et al. 1988 |
| Hazelnut (Nuts,
Peanuts, Seeds)
walnut, brazil nut, almond, pecan, pistatio, pine nut, peanut, sesame seeds * |
111 peanut and/or tree nut allergic patients: strong correlation (r >0.7) between hazelnut and walnut, brazil nut, almond, and sesame; moderate correlation (r >0.6) between hazelnut and peanut, pecan, pistachio, and pine nut (RAST) | Sicherer et al. 1998 |
| Hazelnut (Fruits, Seeds)
kiwi fruit, poppy seeds, sesame seeds |
8 Patients with food / pollen allergy (immunoblot inhibition) | Vocks et al. 1993 |
| Hazelnut (Fruits)
kiwi fruit |
3 kiwi allergic patients: moderate inhibition of IgE- binding to kiwi extract by hazelnut extract (RAST inhibition) | Gall et al. 1994 |
| Hazelnut (Rye)
rye flour * |
Correlation between specific IgE to rye flour and nuts (peanut, almond, brazil nut, coconut, hazelnut) (3310 atopic patients, RAST, r = 0.5 to 0.8) | Seifert et al. 1988 |
| Hazelnut (Various
Foods)
kiwi fruit, poppy seeds, sesame seeds, rye flour |
5 patients: 50 to 100% inhibition of IgE- binding to
poppy seed by hazelnut;
2 patients each: 56 and 84% inhibiton to kiwi by hazelnut, 78 and 91% inhibition to sesame seed by hazelnut; 1 patient: 77 and 84% inhibition to rye flour by hazelnut and vice versa (RAST inhibition) |
Seifert et al. 1988 |
9 Allergenicity of Different Hazelnut
Varieties
| Varieties / Subjects | Differences | References |
| 6 Hazelnut Varieties
hazelnut allergic patients |
No significant differences in relative amounts of allergens (SDS-PAGE / immunoblot) | Vieths et al. 1998 |
| 5 Hazelnut Varieties
8 hazelnut allergic patients |
Similar IgE binding patterns to all varieties, slight
differences as regards intensity of detection (SDS-PAGE / immunoblot)
Minor differences in IgE-binding potencies of varieties: Contorta (Germany) > Barcelona (USA) > Levantiner (Turkey) and Neapler (Sicily) > Römer (Italy) (EAST inhibition) |
Wigotzki et al. 2000b |
10 Stability of Hazelnut Allergens
| Treatment | Effects | References |
| Hazelnuts (Storage)
storage (1 to 19 weeks at room temperature) |
No significant differences as compared to native hazelnuts (SDS-PAGE immunoblot, EAST inhibition) | Wigotzki et al. 2000b |
| Hazelnuts (Heat)
heating to 100°C for 30 min |
Heating of the food reduced allergenic activity in anti-birch pollen IgE system, while considerable activity was retained in anti- hazelnut IgE system (RBL cell mediator release assay) | Vieths et al. 1998 |
| Hazelnuts (Heat)
roasting to 140°C for a) 20 min and b) 40 min |
Positivity in SPT with:
raw hazelnuts 95% roasted hazelnuts a) 47% roasted hazelnuts b) 11% (19 patients with positive DBPCFC to hazelnut) |
Ballmer-Weber et al. 2000 |
| Hazelnuts (Heat)
heating of ground hazelnuts at 100-185°C for 15-90 min (dry heating oven) or microwave heating (630 W, 10 min) |
No reduction of IgE binding after heating 100°C for 90 min or after microwave treatment; decrease of IgE binding after heating to >100°C for 15 min; after heating to >170°C the major allergens abolished in immunoblotting; a minor allergen with <14 kDa detectable after heating up to 185°C for 15 min (19 hazelnut allergic patients, SDS-PAGE immunoblot, EAST inhibition) | Wigotzki et al. 2000b |
| Hazelnuts (Hydrolysis)
2 step digestion with a) pepsin (2 h) and b) pancreatic enzymes (45 min) (extract from hazelnuts) |
IgE-binding after combined hydrolysis (a + b) of hazelnut proteins reduced to <10% as compared to native protein extract (EAST, hazelnut allergic patients) | Vieths et al. 1999 |
| Hazelnuts (Enzymic Hydrolysis)
hydrolysis of hazelnut proteins up to 240 min with a) pepsin b) trypsin, elastase, and protease (from Tritirachium album) c) pancreatin |
a) only slightly decrease in IgE-binding after peptic
hydrolysis for 60 min (maximum EAST inhibition appr. 65%); after 240 min
maximum EAST inhibition was about 40% as compared to native hazelnut extract
and 2/7 sera still showed IgE-binding in SDS-PAGE immunoblot
b) hydrolysis with trypsin, elastase, and protease (from Tritirachium album) significantly decreased IgE-binding after 30 min of treatment to a maximum EAST inhibition <30% c). Hydrolysis with pancreatin for 60 min reduced IgE-binding to < 30% maximum inhibition (15 hazelnut allergic patients) |
Wigotzki et al. 2000a |
| Reported Adverse Reactions | References |
| Food / Food additives
After ingestion of hazelnuts (1) Ingestion of hazelnut fragment in muesli (2) Accidental ingestion of tree nuts by 30% of tree nut allergic patients over a period of 5.5 years (3) |
(1) see 2 Symptoms of Hazelnut Allergy
(2) Ewan 1996 (3) Sicherer et al. 1998 |
| Chocolate
Asthma after ingestion of 3-6 g of chocolate containing 0.2% of hazelnut proteins (1) |
(1) Malmheden Yman et al. 1994 |
| Potential Adverse Reactions | References |
| Food compounds
Nickel allergy: Consumption of hazelnuts in larger amounts may increase the nickel intake, which potentially could elicit nickel allergic reactions (2) Salicylic acid intolerance: Correlation between acetylsalicylic acid intolerance and hazelnut hypersensitivity maybe due to natural content of salicylic acid (1129 adults with bronchial asthma and/or allergic rhinitis, questionaire) (1) |
(1) Eriksson 1978
(2) Flyvholm et al. 1984 |
| Allergens in Hazelnut Products | Content / Products | References |
| Hazelnut Allergens
hazelnut oil (blend of refined and unrefined oils) and pool serum from 17 nut or peanut allergic patients |
Protein content in hazelnut oil: 62 µg/ml; IgE- binding to protein extract in dot immunoblot | Teuber et al. 1997 |
| Hazelnut Proteins
commercial food products without labeling of hazelnut |
a) Amounts of hazelnut between
1.8 and 421 mg/kg in 14 of 27 samples (ELISA, polyclonal antibodies,
limit of detection 0.002%)
b) Qualitative detection of hazelnut in the same samples as a), no false positive results (hazelnut specific PCR detection of 182bp product from cDNA of Cor a 1.0401, limit of detection 0.001%) |
a) Holzhauser & Vieths
1999
b) Holzhauser et al. 2000 |
| Hazelnut Proteins
samples assumed to be free of hazelnuts: chocolate spread, chocolate bar, chocolate cookie, muesli cookie, and cake |
Amounts of hazelnut between 3.4 and 752 mg/kg in 15 of 26 samples; a complaint sample of chocolate spread contained 4 g/kg of undecleared hazelnut (ELISA, rabbit-antibodies) | Koppelman et al. 1999 |
| Food Allergen | Labelling / Regulation Status | References |
| International Regulations
Tree nuts* and products of these |
mandatory labeling of prepackaged food / advisary status (1) | (1) Codex Alimentarius Commission 1999 |
| European Regulations
Tree nuts* and products of these |
labeling appropriate / recommendation (1) | (1) Bousquet et al. 1998 |