Peanut Allergy

Conference coverage

Synopsis: At the Travel Medicine meetings in Montreal, a symposium on food and water issues featured a presentation by one of our Associate Editors, Phil Fischer, who is a pediatrician recently translocated to the Mayo Clinic. Conference organizers asked him to provide a perspective on the peanut allergy issue and airlines policy in addition to its place in the consideration of food allergies in general.

Source: Symposium S9, Safe Food, Safe Water. Philip R. Fischer. Pediatric Allergies and Travel. Abstracts of the 6th Conference of the International Society of Travel Medicine. S9.3 p 58, 1999.

The quest for safe food usually focuses on the avoidance of food contaminated by infectious pathogens. Disease, however, results from the interaction between external agents and host responses. Some symptoms in travelers, 6th CISTM participants were reminded, result from hypersensitive or allergic reactions to foods uncontaminated with such pathogens.

Foods most commonly known to trigger allergic reactions include milk, eggs, peanuts, tree nuts, and seafood. Milk and egg sensitivities usually subside or resolve over a period without exposure, but "nut" allergies (which may be related to the peanut, a legume, or to tree nuts) and seafood sensitivity are usually lifelong.

Peanut allergy has frequented headlines of the lay press in recent years. While some 15% of children experience some sort of allergic disease, about 1% of people are allergic to peanuts. Most people who react to peanuts are also atopic or asthmatic and have other food sensitivities as well.

Reactions to peanuts often occur on the occasion of the child’s first known exposure to peanuts. It is not clear if the child had intrauterine sensitization, was exposed to peanut allergen via breastfeeding, or had previously unknowingly ingested peanut-containing foods. The mean age of the first reaction to peanuts is two years.

While peanut reactions can be mild, anaphylaxis also may occur. Some individuals are so sensitive that they may respond to extremely small exposures of peanut allergen via either the inhalational or transcutaneous routes.

Published series of fatal and near-fatal food-induced anaphylaxis are instructive. First, essentially all severely affected individuals reacted to a food to which they were already known to be allergic. Even after anaphylactic reactions, it is not unusual to "accidentally" ingest the anaphylaxis-provoking food. Second, in most all fatal cases of food-induced anaphylaxis, epinephrine was not given within the first 25 minutes of the beginning of symptoms of anaphylaxis. Thus, travel medicine practitioners should warn food-sensitive travelers to be particularly vigilant about checking food contents and avoiding the ingredients to which they are sensitive. Food-allergic travelers should always travel with readily available epinephrine and with someone who could administer it.

What about peanuts on airplanes? Some airlines now offer "peanut-free flights" on request from peanut-allergic flyers. Nonetheless, there is no way to completely prevent the presence of allergens in carry-on luggage, and many peanut-sensitive individuals are also allergic to other foods. Individual travelers should monitor their foods, but there is no feasible way to fully legislate completely safe, allergen-free flights. The best approach to peanut allergy in travelers seems to be to focus more on individual education and the provision of epinephrine than on policy or legislative measures to regulate airline food.

References

1. Anderson JA. Milk, eggs and peanuts: Food allergies in children. Am Fam Phys 1997;56:1365-1374.

2. Hourihane JO’B, et al. Clinical characteristics of peanut allergy. Clinical Experimental Allergy 1997; 27:634-639.

3. Sampson HA, et al. Fatal and near-fatal anaphylactic reactions to food in children and adolescents. N Engl J Med 1992;327:380-384.

4. Sicherer SH, et al. Clinical features of acute allergic reactions to peanut and tree nuts in children. Pediatrics 1998;102:e6.

5. Yunginger JW, et al. Fatal food-induced anaphylaxis. JAMA 1988;260:1450-1452.

Peanut allergy:

a. affects about 20% of the population.

b. is uniformly fatal.

c. is usually outgrown by age 5 years.

d. is impossible on "peanut-free" flights.

e. can occur the first time someone eats peanuts.