By Maggie A. Williams, M.D.

Many people do not realize how serious food allergies can be. While food allergies are usually mild (and probably more common than many of us realize), a nut allergy is one type of allergy that can be life-threatening.

Nuts, especially peanuts, are found in many foods that do not look or taste like they contain them. For parents of children who are allergic to one or more types of nuts, every meal, treat and snack needs to be scrutinized carefully. Take-out food can be a chore instead of a convenience. Food at family gatherings is subjected to an exhaustive ingredient analysis. Birthday parties and Halloween can become a nightmare.

What is an allergy? Our bodies are exposed to a variety of substances everyday through the foods we eat and the plants, chemicals and pets in our environment. An allergic reaction is when the body’s immune system thinks that a normally harmless substance is harmful and tries to protect the body by getting rid of the substance. This process involves the production of antibodies called immunoglobulin E (IgE) against the offending substance (called an antigen). An allergic reaction produces symptoms that can be annoying (itchy watery eyes, runny nose) to life-threatening (anaphylaxic shock).

The American Academy of Allergy, Asthma, and Immunology estimates that up to 2 million, or 8 percent, of children in the United States may have a food allergy. The most common allergies are to eggs, fish, milk, peanuts, shellfish, soy, tree nuts and wheat. Allergies tend to be hereditary (meaning the likelihood of getting allergies is genetic), although this is not true in all cases. Allergies also may tend to grow more severe with time.

For unknown reasons, the number of people in the United States with a peanut allergy has risen in recent years. Approximately one-fourth of people who are allergic to peanuts (not a “true” nut) will also be allergic to “true” nuts or tree nuts (walnuts, cashews, etc.). The average age of diagnosis is usually around two years old.

The first symptoms of a peanut or tree nut allergic reaction may be apparent within minutes to hours after exposure. The symptoms may range from a mild rash to itching or swelling of the mouth, nose, throat or face.

If you are concerned that your child may have an allergy, talk to your doctor. Special blood and skin tests can help determine if there is a problem.

Here is a list of tips for people caring for children with peanut and tree nut allergies:

• Check food labels and stay clear of foods that you are not certain are peanut or tree nut free.
  
• Consider writing an action plan with specific instructions as to when to give the child an injection of epinephrine to prevent anaphylaxic shock caused by eating peanuts or tree nuts. Give copies of this plan to friends and family members and teach them how to use an injectable epinephrine device.
  
• Carry injectable epinephrine and over-the-counter antihistamine at all times. Both can be useful, although an antihistamine is never a substitute for injectable epinephrine.
  
• Teach allergic children old enough to give themselves epinephrine injections how to use an injectable epinephrine device. Injectable epinephrine pen devices come with a “trainer” pen that can be helpful when learning how to use the device.
  
• Injectable epinephrine devices should be available at your home and other locations where the child spends time.
  
• Talk to the child’s teachers, school principal and child care providers about your action plan. Keep injectable epinephrine in these locations, as well.
  
• Consider a medical alert bracelet for the child.
  
• A child that has been given injectable epinephrine should be seen immediately in a medical facility or emergency department. Do not hesitate to call 911 as treatment can be started during the ambulance ride to the hospital.
  
• A child should be evaluated by a physician after exposure to peanuts or tree nuts - even if the condition was treated at home and the child appears to get better. The condition could worsen over the next several hours and should be observed in a medical setting.

Thankfully, with more information and awareness about severe food allergies, all those involved in the lives of children with peanut and tree nut allergies can now help care for these children’s health.Dr. Williams as internal medicine physician at PAMF’s Los Altos Center.