by Seth Craig, M.D.

Peanuts were first cultivated in South America over 4,000 years ago. After the European conquests, peanuts were brought to the Caribbean and later to the southern United States before being traded throughout Europe, Africa and Asia. Peanuts served as an important source of food for Civil War soldiers and gradually peanut products became commonplace in the North American diet.

Allergic reactions to peanuts have been known for many years, but have increased in the past twenty years. Now peanut allergy occurs in over 1 percent of American children and it is the most common reason for children arriving in emergency departments for anaphylaxis (severe allergic reactions). Only one out of five of these children will outgrow peanut allergy.

Signs and Symptoms

Signs and symptoms of peanut allergy include hives, worsening eczema, wheezing, throat itching or swelling, swelling of the face and lips, nasal congestion, difficulty breathing or swallowing, heartburn, vomiting, diarrhea, acute or chronic abdominal pain, sudden weakness, or sudden shaking or confusion. It is important that emergency treatment in the form of injectable epinephrine, such as EpiPen, be administered immediately. The sooner the medication is given, the better the result.

What to Do

When peanut allergy is suspected the child or adult should see an allergist to establish a definite diagnosis and recommend treatment. Strict avoidance of peanut products is the best preventative, although research is in progress to develop a peanut vaccine, finding ways to build oral tolerance and even to determine whether certain Chinese herbs can suppress allergic reactions.

Warnings and Precautions

For years it was assumed that a person had to ingest peanuts in order to become allergic to it. Recent research suggests that sensitivity to peanuts can develop from skin contact. It is not known if inhaling peanut fumes can cause the allergy to develop, but airborne exposure can trigger symptoms in some people. The person with a suspected peanut allergy should avoid skin contact with peanut products, as well as avoid eating these products. It is important to read food labels. Avoid foods with the disclaimer that they may contain peanuts or were manufactured in a factory that also processes peanut products. Approximately 7 percent of these "may contain" products actually are contaminated with the unwanted allergen. Peanut oils vary in how much of the peanut allergen they contain and these too should be avoided. Speaking of cross-contamination, use special care at food bars where serving utensils may have touched a peanut product and then used to serve another food. Jelly jars at home may pick up peanut allergen if the spoon used in the peanut butter was then used to get the jelly. In restaurants it is important to discuss with the manager which foods may potentially be contaminated. As opposed to some other food allergens, the peanut allergens are not destroyed by cooking.

In conclusion

Remember to have the injectable epinephrine immediately available at all times (within one minute) of where the child or adult is located. This does require speaking with school authorities to arrange this for school children. Be sure to watch for signs of other allergies developing. About 30 percent of children allergic to peanut may become allergic to tree nuts, as well. In addition to the allergy office there are internet resources for further information such as the Food Allergy and Anaphylaxis Network at www.foodallergy.org.

Seth Craig, M.D.