Peanut Allergy

Overview

Peanut allergy affects approximately 1.5 million people in the United States. As the most common cause of life-threatening allergic reactions (anaphylaxis), peanut allergies account for 80 percent of fatal or near-fatal allergic reactions each year. You can reduce your risk of having an allergic reaction to peanuts by knowing as much as you can about peanut allergy and how to avoid peanut-containing products.

If you have any reaction to peanuts, tell your doctor about it, no matter how mild the reaction may have been. Tests can help diagnose peanut allergy, so you can take steps to avoid future and potentially worse reactions.

Signs and symptoms

There's a difference between peanut allergy and peanut intolerance. Sometimes it can be difficult to know whether you are allergic or intolerant to peanuts.

§ Peanut intolerance. 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.

§ Peanut allergy. An allergy to peanuts 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.

Peanut allergies trigger an immune system response. Your immune system reacts to proteins found in peanuts. Exposure to peanuts or traces of peanuts may cause immediate reactions, such as itching, redness, swelling, shortness of breath, wheezing, nausea, abdominal pain, lightheadedness or loss of consciousness (anaphylaxis).The chemicals in peanuts can cause hives to develop on the areas of your skin that have come in contact with peanuts or traces of peanuts. Hives may spread to the rest of your body.

Allergic reactions to peanuts usually occur within minutes after exposure, although reactions within an hour or so after ingestion are possible. Signs and symptoms can range in severity depending on which body systems are involved in a reaction and how much peanut protein you've been exposed to.

The most serious and potentially deadly allergic reaction to peanuts is an anaphylactic response. If you are highly sensitive, an anaphylactic reaction can develop immediately after peanut exposure, causing the airways (bronchi) to constrict, making breathing difficult. Blood pressure may drop to life-threateningly low levels, making you feel dizzy or lose consciousness. Other serious signs and symptoms of an anaphylactic reaction include:

§ Wheezing

§ Rapid or weak pulse

§ Blueness of your skin, including your lips and nail beds

§ Diarrhea

§ Nausea and vomiting

§ Dizziness

§ Loss of consciousness

Seek emergency medical care if you or someone else develops an anaphylactic reaction.

Risk factors

It isn't clear why some people develop allergies while others don't. However, people with certain risk factors have a greater chance of developing peanut allergy:

§ Family history of allergies. You're at increased risk of peanut allergy if other allergies, especially other types of food allergies, are common in your family. A child's first allergic reaction to peanuts usually occurs between ages 1 and 2.

§ Personal history of peanut allergy. About 20 percent to 25 percent of children with peanut allergy outgrow it. However, even if you seem to have outgrown peanut allergy, there is still a small risk it will recur.

§ Altered immune system. According to recent studies, the prevalence of peanut allergy has doubled in young American children in the last five years. Although reasons are unknown, some scientists believe that the destroying of many infectious diseases may have altered the immune system. Other experts suggest that improved hygiene is involved, proposing that higher standards of cleanliness in Western countries may have confused our immune systems, increasing the chances of developing allergies later in life, when the immune system is usually more prepared to prevent allergies from occurring.

When to seek medical advice

Talk to your doctor if you think you're allergic to peanuts or if you have peanut allergy symptoms. If possible, see your doctor while you have symptoms. Seek emergency medical treatment if you develop any signs or symptoms of anaphylaxis.

Screening and diagnosis

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 one or both of the following tests:

§ Skin test. In this test, your skin is pricked and exposed to small amounts of the proteins found in peanuts to see if you have a skin test 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 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.

Treatment

Medications, such as antihistamines, may reduce symptoms of peanut allergies. These drugs can be taken after exposure to peanuts to control your reaction and help relieve discomfort. However, the only way to prevent an allergic reaction is to avoid peanuts and peanut proteins altogether.

Despite your best efforts, you may still come into contact with peanuts and have a severe reaction. In this case, you may need an emergency injection of adrenaline (epinephrine) and a trip to the emergency room. If you're at risk of having a severe reaction, you may need to carry injectable epinephrine with you at all times.

Prevention

The best way to prevent an allergic reaction to peanuts is to know and avoid foods that cause signs and symptoms. In some foods, peanuts may be well hidden. This is especially true in restaurants and in other social settings.

If you know you have peanut allergy, follow these steps:

§ Know what you're eating and drinking. Be sure to read food labels carefully.

§ If you've already had a severe reaction to peanuts, wear a medical alert bracelet or necklace.

§ Talk with your doctor about carrying emergency medications.

If your child has peanut allergy, take these precautions to ensure his or her safety:

§ Notify key people that your child has peanut allergy. Talk with child care providers, school personnel, parents of your child's friends, and other adults who regularly interact with your child. Emphasize that an allergic reaction can be life-threatening and requires immediate action. Make sure that your child also knows to ask for help right away if he or she reacts to peanuts.

§ Explain peanut allergy symptoms. Teach the adults who spend time with your child how to recognize signs and symptoms of an allergic reaction to peanuts.

§ Write an action plan. Your plan should describe how to care for your child when he or she has an allergic reaction to peanuts. Provide a copy of the plan to your child's school and to others who care for and supervise your child.

§ Have your child wear a medical alert bracelet or necklace. This alert lists your child's allergy symptoms and explains how others can provide first aid in an emergency.

§ Discourage your child from sharing foods. It's common for kids to share snacks and treats. However, during times of fun your child may forget about food allergies or sensitivities. If your child is allergic to peanuts, encourage him or her to refrain from eating food from others.

Peanut allergy: Can a child outgrow it?

Q. Can a child outgrow a peanut allergy?

A. Yes, About 20 percent to 25 percent of children with peanut allergy will outgrow it. But there is a small risk it will return. Peanut allergy affects 1 percent to 2 percent of young children and is the most common cause of anaphylaxis, a life-threatening allergic reaction.

It's difficult to predict which children will outgrow peanut allergy. Some research suggests that children with lower levels of peanut allergy-specific antibodies (IgE) may be more likely to outgrow peanut allergy than children with higher levels of these antibodies. IgE is measured by a blood test.

Even when a child appears to outgrow peanut allergy, there is a small risk it will recur. A study published in November 2004 suggested that the way to reduce the risk of recurrence is to encourage the child to eat peanuts on a regular basis. This may seem odd advice to parents who have drilled a fear of peanuts into their children. But the study found peanut allergy was much less likely to return in children who ate peanuts at least once a month after developing a tolerance for them than in children who largely avoided peanuts.

How do you know if your child has outgrown peanut allergy? Children with known peanut allergy should be re-evaluated by a board-certified allergist before discontinuing any preventive or avoidance measures. Even if it is determined that a child has outgrown peanut allergy, doctors still recommend that the child continue to carry injectable epinephrine in case the allergy returns.

Peanut allergy: Is Nutella a safe substitute for peanut butter?

Q. Can he safely use Nutella in place of peanut butter?

A. Nutella is a chocolate hazelnut spread that also contains peanut oil. Some individuals with a peanut allergy may safely consume peanut oil. But there is a chance that the peanut oil could contain some proteins from the peanut, which would make it unsafe for people with peanut allergy. It is probably best to avoid using anything that contains peanut oil unless your son's allergist has told you that it is OK.

Also, many allergists recommend that people with peanut allergy also avoid tree nuts — such as hazelnuts — as an added precaution. Check with your doctor regarding your son's specific allergy restrictions.

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