click for more images

Anaphylaxis is the greatest risk from peanut allergies.

A.D.A.M. Medical Encyclopedia

Newsletters & RSSEmail to a friendPrint this PageSubmit to Digg

Peanut-Free Recipes

Substitutes for Peanut ButterPeanut-Free RecipesAllergy-Safe Vegetable Broth

Lifestyle Resources for Peanut Allergies

Eating Out with AllergiesHow to Make Substitutions in RecipesFirst Five Things to Do After Being Diagnosed with a Peanut Allergy

Suggested Reading

Diagnosing Food AllergiesWhat should I do if I think my child has a food allergy?My Child's School is Nut-Free. Why Is This Necessary?

Most Popular

Food Allergy SymptomsWheat AllergiesDairy AllergiesShellfish AllergyTree Nut Allergies

Peanut Allergies

Overview:

Peanut allergies aren't the most common food allergies in America —dairy in children and shellfish in adults—but they certainly have the highest profile. They are often severe and pose a major challenge to parents wanting to keep their kids safe in school or other public places; those who suffer from a peanut allergy may react to traces of peanut proteins left on countertops and other surfaces. Peanut allergies sometimes wane with age, but this is not particularly common. Around 80 percent of children diagnosed with peanut allergies will have them for life.

Risk Factors for Peanut Allergy:

Researchers have identified several risk factors for peanut allergies that can't be controlled. These include being born into an atopic family (one with a history of allergies) and having certain types of skin conditions, like eczema. Parents can help protect children by avoiding use of peanut oil-containing lotions and feeding babies soy formulas (breastfeeding or hydrolyzed formulas are considered safer for infants at high risk of allergies.) Current recommendations for atopic families are that women not eat peanuts while pregnant or nursing and that peanuts not be fed to kids until age three.

Symptoms:

Peanut allergies can cause virtually any common food allergy symptom. The reason peanut allergies are so problematic, however, is that they're much more likely than many other allergies to cause reactions throughout your whole body. The riskiest of these is anaphylaxis, which, among other things, can cause your airway to swell and blood pressure to drop dangerously low. It is because of the possibility of a life-threatening reaction that anyone diagnosed with a peanut allergy should carry injectable epinephrine at all times and know how to administer emergency treatment for anaphylactic shock.

Cross-Reactivity:

People with peanut allergies are at high risk for quite a few other allergies. Reactions to tree nuts (which include most other nuts) and other legumes, like peas, are the most common, although most people with peanut allergies do tolerate soy. One study even indicated some possibility of cross-reactivity between peanuts and citrus seeds.

Inhalation Reactions to Peanut Proteins:

Contrary to a widely held belief, it is not possible to have a true allergic reaction from the aroma of peanuts, although fear from recognizing the smell of peanuts may lead to a psychosomatic reaction. The chemicals which cause smells (pyrazines) are not related to the proteins that trigger allergic reactions. There are, however, reports of airborne fragments from peanut shells causing reactions, although these may be rarer than popularly believed.

Emerging Treatments for Peanut Allergies:

Because peanut allergies are so severe, a great deal of research has been devoted to trying to find a cure for them. While late-stage clinical trials on a promising medicine, Xolair, were halted, researchers have reported promising results from low-dose immunotherapy. This is not considered a widely-used treatment or cure but rather a way to increase tolerance in the event of accidental ingestion. The Duke Food Allergy Initiative, which has been running several immunotherapy studies, hopes to have concrete results within the next several years.

Foods Commonly Containing Peanuts:

Aside from the obvious foods (peanut butter, etc.), peanuts are commonly found in chocolate candies, Asian sauces and dishes (especially Chinese, Thai, Vietnamese, and Malaysian), packaged goods (such as snack foods), and all sorts of baked goods. Some granolas and cereals are made with peanuts, as are some products marketed towards vegetarians. Home cooking with peanut allergies can be simple if you stick to fresh, unprocessed ingredients like fruits, vegetables, meats, dairy products, and whole grains.

Peanuts and Labeling Laws:

Because peanuts are one of the eight most common allergens in the United States, the Food Allergen Labeling and Consumer Protection Act (FALCPA) requires manufacturers to clearly indicate the presence of peanuts on food labels. Arachis oil is the most common alternate name for peanuts.

Be aware that FALCPA does not require manufacturers to indicate that products were processed in a facility or on a line where peanuts were processed, though many do so voluntarily. It's safest for people with peanut allergies to avoid any products marked in this manner.

Eating Out with Peanut Allergies:

Some restaurants are riskier than others for peanut allergy sufferers. Many Asian cuisines use peanuts and should probably be avoided entirely. A concern at many restaurants is peanut oil. Refined peanut oil is generally considered safe; cold-pressed oil less so. Always check on frying oils. Because of the vast number of packaged foods prepared on the same lines as peanuts, and because of the possibility of cross-contamination, your safest bet is likely to go to a restaurant that makes virtually everything from scratch and that has significant experience with allergies, or one that has no peanuts on the premises.

Living With Peanut Allergies:

Peanut allergies pose unique challenges. People with peanut allergies must be hyper-vigilant about their diets and avoiding contact with surfaces where traces of peanut may have been left behind.

It's possible to avoid some places where peanuts are served, like ballparks, bars, and circuses. Others, like airplanes and schools, may require special arrangements. For more information, see:

• Food Allergies In Schools
• Airline Travel with Allergies

Finding peanut-free packaged foods in supermarkets can be difficult. You can buy peanut-free snacks online from stores like Miss Roben's or Rebecca's Nut-Free Bakery. Amy's Kitchen frozen foods are made in peanut-free (but not tree nut-free) facilities.

Studies have shown that accidental exposure to peanuts is not as frequent as had been thought. However, researchers also note that many severe peanut reactions are not handled properly. If you have been diagnosed with a peanut allergy, make sure to learn the symptoms and proper treatment of anaphylaxis and to always carry injectable epinephrine if prescribed, even if your symptoms have previously been mild.

_Sources:

de Leon, M.P., et al. "IgE Cross-Reactivity Between the Major Peanut Allergen Ara h 2 and Tree Nut Allergens." Molecular Immunology. Jan 2007 44(4):463-71.

Fiocchi, Alessandro, et al. "Food Allergy and the Introduction of Solid Foods to Infants: a Consensus Document." Annals of Allergy, Asthma, and Immunology. Jul 2006 97(1):10-21.

Glaspole, I.N., et al. "Anaphylaxis to Lemon Soap: Citrus Seed and Peanut Allergy Cross-Reactivity." Annals of Allergy, Asthma & Immunology. Mar 2007 98(3):286-9.

Lack, Gideon, et al. "Factors Associated with the Development of Peanut Allergy in Childhood." New England Journal of Medicine. Mar 13, 2003 348(11):977-85.

O'B Hourihane, et al. "Randomised, Double Blind, Crossover Challenge Study of Allergenicity of Peanut Oils in Subjects Allergic to Peanuts." BMJ Apr 12, 1997 314(7087):1084 11 Jun 2007.

Perry, Tamara T., et al. "Distribution of Peanut Allergen in the Environment." JACI. May 2004 113(5):973-76.

Wensing, M., et al. "Patients with Anaphylaxis to Pea can have Peanut Allergy Caused by Cross-Reactive IgE to Vicilin." JACI. Feb 2003 111(2):420-4.

Yu, Joyce W., et al. "Accidental Ingestions in Children with Peanut Allergy." JACI. Aug 2006 118(2):466-72.