Q:

11/16/2011
What are the most common tree nut allergies?

A:

Thank you for your recent inquiry.

Unfortunately, there are no definitive data on the most common tree nuts to cause reactions. Almost all the information we have has been gleaned from surveys, and the results from these surveys can differ. Results are dependent upon the country assayed and other factors. In addition, none of these studies have involved extremely large numbers of patients. However, at least to give you some help in this regard, I will share with you the information from two such studies.

There is an abstract copied below from a survey taken in Britain and published in the British Medical Journal, and as you can see the nuts responsible for reactions in order of frequency were Brazil nut, almond, and hazelnut. On the other hand, data from a more recent United States survey(1) showed for tree nuts, the most common offenders, in descending order of frequency, were: Cashew, hazel, almond, walnut, macadamia, pistachio, pecan, pine, and Brazil nuts.

Thank you again for your inquiry and we hope this response is helpful to you.

BMJ 1996; 312 doi: 10.1136/bmj.312.7038.1074 (Published 27 April 1996) Cite this as: BMJ 1996;312:1074
Abstract
Objective: To investigate clinical features of acute allergic reactions to peanuts and other nuts.
Design: Analysis of data from consecutive patients seen by one doctor over one year in an allergy clinic at a regional referral centre.
Subjects: 62 patients aged 11 months to 53 years seen between October 1993 and September 1994.
Main outcome measures: Type and severity of allergic reactions, age at onset of symptoms, type of nut causing allergy, results of skin prick tests, and incidence of other allergic diseases and associated allergies.
Results: Peanuts were the commonest cause of allergy (47) followed by Brazil nut (18), almond (14), and hazelnut (13). Onset of allergic symptoms occurred by the age of 2 years in 33/60 and by the age of 7 in 55/60. Peanuts accounted for all allergies in children sensitised in the first year of life and for 82% (27/33) of allergies in children sensitised by the third year of life. Multiple allergies appeared progressively with age. The commonest symptom was facial angioedema, and the major feature accounting for life threatening reactions was laryngeal oedema. Hypotension was uncommon. Of 55 patients, 53 were atopic—that is, had positive skin results of tests to common inhaled allergens—and all 53 had other allergic disorders (asthma, rhinitis, eczema) due to several inhaled allergens and other foods.
Conclusions: Sensitisation, mainly to peanuts, is occurring in very young children, and multiple peanut/nut allergies appear progressively. Peanut and nut allergy is becoming common and can cause life threatening reactions. The main danger is laryngeal oedema. Young atopic children should avoid peanuts and nuts to prevent the development of this allergy.

For tree nuts, they were cashew, hazel, almond, walnuts, macadamia, pistachio, pecan, pine, and Brazil nuts, also in decreasing order of frequency.

Reference:
1. J Allergy Clin Immunol 2010; 126(2):324-331.

Sincerely,
Phil Lieberman, M.D.

AAAAI - American Academy of Allergy Asthma & Immunology