Peanut allergy is common and often appears in the first years of life. While many children outgrow allergies to other foods such as milk or eggs, most kids don’t outgrow peanut allergy as they get older.
An allergic reaction to peanuts can range from a minor irritation to a life-threatening reaction called anaphylaxis. Even people who have only had a mild reaction in the past are at risk of a more serious future reaction.
If your child has a peanut allergy — or you’re an adult who has had a reaction — tell your doctor about it, even if it was minor. Tests can help confirm a peanut allergy, so you can take steps to avoid future and potentially worse reactions.
An allergic response to peanuts usually occurs within minutes after exposure, and signs and symptoms range from mild stomach or skin reactions to anaphylaxis, a life-threatening reaction that can constrict the airways and block breathing.
Signs and symptoms of peanut allergy can include:
- Skin reactions such as hives, redness or swelling
- Itching or tingling in or around the mouth and throat
- Digestive problems such as diarrhea, stomach cramps, nausea or vomiting
- Tightening of the chest
- Shortness of breath or wheezing
- Runny or stuffy nose
Peanut allergy is the most common cause of anaphylaxis, a medical emergency that requires treatment with an epinephrine (adrenaline) injector (EpiPen, Twinject) and a trip to the emergency room. Signs and symptoms start soon after consuming peanuts and can include:
- Constriction of airways, including a swollen throat that makes it difficult to breathe
- Shock, with a severe drop in blood pressure
- Rapid pulse
- Dizziness, lightheadedness or loss of consciousness
Peanut allergy occurs when your immune system develops allergy-type antibodies to peanut proteins. Your immune system mistakenly identifies the proteins as something harmful. The next time you come in contact with peanuts, these antibodies recognize it and signal your immune system to release chemicals such as histamine into your bloodstream, which leads to the signs and symptoms of an allergic response. Scientists aren’t sure why some people become allergic to peanuts and others don’t.
Exposure to peanuts can occur in three ways:
- Direct contact. The most common cause of peanut allergy is eating peanuts or peanut-containing foods. Sometimes direct skin contact with peanuts can trigger an allergic reaction.
- Cross-contact. This is the unintended introduction of peanuts into a product. It’s generally the result of exposure to peanuts during processing or handling of a food product.
- Inhalation. An allergic reaction may occur if you inhale dust or aerosols containing peanuts, such as that of peanut flour or peanut oil cooking spray.
Your doctor will want to know your signs and symptoms and may want to conduct a physical examination to identify or exclude other medical problems. He or she may also recommend consultation with an allergist, who may request one or both of the following tests:
- Skin prick test. With this test, your skin is pricked and exposed to small amounts of the proteins found in peanuts to see if you have a skin response. If you’re allergic, you develop a raised bump (hive) at the test location on your skin. Allergy specialists usually are best equipped to perform allergy skin tests.
- Blood test. A blood test (sometimes called the radioallergosorbent test, or RAST) can measure your immune system’s response to peanuts by measuring the amount of certain antibodies in your bloodstream, known as immunoglobulin E (IgE) antibodies. A blood sample is sent to a medical laboratory, where it can be tested for evidence of sensitivity to peanuts.
Is it peanut allergy? Or is it peanut intolerance?
Not all adverse reactions to peanuts are caused by an allergic reaction. It can be difficult to know whether you are allergic or intolerant to peanuts.
- If you have peanut intolerance, you usually can eat small amounts of peanuts with only mild symptoms, such as indigestion or heartburn, or no reaction at all. A peanut intolerance doesn’t involve your immune system.
- An allergy involves an immune system response. Even a tiny amount of peanuts may trigger a serious allergic reaction. Tests can help determine whether you have true peanut allergy.
The only way to prevent an allergic reaction is to avoid peanuts and peanut proteins altogether. But peanuts are common, and despite your best efforts, you or your child is likely to come into contact with peanuts at some point.
While most reactions to peanuts are not life-threatening, it’s important to be prepared for a severe reaction. For an anaphylactic reaction, an emergency injection of adrenaline (epinephrine) and a trip to the emergency room are necessary. If your doctor thinks you may be at risk of a severe reaction, you’ll probably need to carry injectable epinephrine (EpiPen, Twinject) with you at all times.
Medications, such as antihistamines, may reduce the mild symptoms of peanut allergies. These drugs can be taken after exposure to peanuts to help relieve itching or hives. However, antihistamines are not sufficient to treat severe, life-threatening reactions.