How Do I Know If My Child Has a Peanut Allergy?

If you or your doctor suspects your child has a peanut allergy, you may be referred to an allergist, who can perform tests to diagnose peanut allergies such as a skin test, blood tests, and a food challenge.

• Peanuts, which are actually legumes and not nuts, can cause allergic reactions such as difficulty breathing and other serious health problems in people who are allergic.
• When people have a peanut allergy, the immune system overreacts to proteins, which results in the symptoms of an allergic reaction. 
• Nearly 2.5% of children in the U.S. are thought to have a peanut allergy. 
• If you or your doctor suspects your child has a peanut allergy, you may be referred to an allergist, which is a doctor who specializes in the treatment of allergies. 

Tests used to diagnose allergies such as peanut allergies include: 

• Skin test 
  • A small scratch is made on the skin and a small amount of liquid extract of the nut is applied
  • If there is a reaction, such as a raised spot (wheal or hive), skin redness, or itching, it usually means there is an allergy
• Blood tests
  • Antibody test: The blood is drawn and sent to a lab where it is mixed with the allergen and checked for IgE antibodies, a type of protein the body produces when it has an allergic reaction
  • Component testing: Looks for IgE to several different proteins found in peanuts, to can give the doctor additional information about the allergy and the best way to manage it
• Food challenge
  • Involves gradually eating a serving of peanuts and seeing whether it causes symptoms
  • Usually done only when other tests are not clear or to check if an allergy has gone away
  • For safety reasons, this test must be done ONLY in a doctor's office or hospital

Do not attempt to test if your child has a peanut allergy at home, as a severe life-threatening allergic reaction (anaphylaxis) could occur. The doctor’s office has medications to treat severe allergic reactions.

Symptoms of a peanut allergy usually occur within minutes to hours after eating peanut and may include: 

• Difficulty breathing
• Wheezing
• Hoarseness
• Throat tightness
• Coughing
• Sneezing
• Upset stomach
• Nausea 
• Vomiting
• Diarrhea
• Itchy, watery, or swollen eyes
• Hives
• Puffiness of the face, eyelids, ears, mouth, hands, or feet 
• Dizziness 
• Fainting
• Anxiety or a feeling something bad is happening
• Anaphylaxis
  • A severe, sudden, life-threatening allergic reaction
  • Drop in blood pressure
  • Airways narrow making it harder to breathe
  • Tongue swelling
• Death (very rare)

Uncommonly, peanut allergies may also trigger other symptoms hours to days after eating peanut such as:

• Eczema: skin itching and flaking
• Eosinophilic esophagitis: heartburn and/or difficulty swallowing food 

The best treatment for peanut allergy is to avoid peanuts, and also any foods that may contain peanuts. 

• Read food labels carefully
• Some foods may not contain peanuts but are produced in factories that make other items that contain nuts
• Equipment may be used for both types of foods and cross-contamination may occur
• Some countries (including the U.S.) have laws that require companies to clearly list whether a food has peanuts in it
  • Check food labels for phrases such as:
    • “May contain peanuts/tree nuts"
    • "Produced on shared equipment with tree nuts or peanuts”
• When dining out, inform servers of the allergy
• Be careful of high-risk foods for people with peanut or tree nut allergy such as:
  • Cookies and other baked goods
  • Candy
  • Ice cream
  • Asian, African, and Mexican foods (which may incorporate peanuts)
  • Sauces (nuts may be used to thicken dishes)
• Make sure children know what foods they can and cannot eat
• Have an emergency plan
  • Antihistamines may be used for mild reactions, but are not to be used as a substitute for epinephrine if a severe allergic reaction (anaphylaxis) occurs
  • People with a diagnosed peanut allergy should have a shot of epinephrine with them at all times
  • Epinephrine injection comes in an easy-to-carry dispenser
  • Parents should notify a child’s teachers, the school nurse, coaches, parents of the child’s friends, and anyone else who may care for the child to know what a reaction looks like and how to respond
    • These people should also know how to reach the parents and the child’s doctor in case of emergency
  • After epinephrine is administered, the child should be taken to the hospital or another medical facility to be monitored for at least 4 hours to make sure the reaction is under control and does not come back