What Is a Peanut Allergy?
You have a peanut allergy when your body’s immune system overreacts to peanuts. Normally, your immune system helps protect you from germs and other harmful substances. But if you have a peanut allergy, your body responds to the proteins in peanuts as though they're dangerous. Your immune system works hard to fight them off, which triggers an allergic reaction.
A peanut isn’t actually a nut. It’s a legume and belongs to the same family as peas and lentils. A peanut allergy is different than a tree nut allergy. Still, up to 40% of people who are allergic to peanuts are also allergic to tree nuts such as almonds, cashews, and walnuts.
Peanuts are often hard to avoid. They can sneak their way into recipes or packaged food items. But even a trace of peanuts can be harmful. That’s why people with peanut allergies need to be extra careful about what they eat.
More than 6 million Americans are allergic to peanuts. Roughly 1 in every 50 kids has a peanut allergy, making it the most common type of food allergy in children. Some grow out of it, but others have a peanut allergy for their whole lives. It's the third most common food allergy among adults.
It's not clear why, but reported cases of peanut allergy have increased in recent years. A 2017 study found the number of children with peanut allergies had increased by 21% since 2010.
Peanut Allergy Causes
When you eat or inhale peanuts, your immune system makes antibodies called immunoglobulin E (IgE). These antibodies travel to cells that release chemicals called histamines. The histamines trigger the allergy symptoms you notice.
Doctors don’t know exactly why some people have immune responses to peanuts and others don’t. Some things that can increase your risk of peanut allergies are:
Your age. Peanut allergies are more common in toddlers and babies. As you grow, so does your digestive system. That’s why older people are less prone to peanut allergy reactions.
Other allergies. If you’re allergic to other foods, you're more likely to also have a peanut allergy. People with other types of allergies, like hay fever, also have a higher risk.
Family history. You may be more likely to have a peanut allergy if someone in your family has one.
Eczema. Eczema is a condition that causes dry and itchy skin. It can raise your risk for peanut allergies.
Prior peanut allergies. Some people outgrow peanut allergies, but they could come back when you're an adult if you had them as a kid.
Peanut Allergy Symptoms
Most often, you’ll notice signs of a reaction within 2 hours of eating peanuts. Your symptoms may be different each time. They can range from mild to life-threatening.
Some common symptoms of peanut allergies are:
- Wheezing or trouble breathing
- Coughing
- Tightness in your throat
- Itching or tingling in your mouth or throat
- Itchy, watery, or swollen eyes
- Runny nose
- Digestive problems, like belly pain, vomiting, nausea, or diarrhea
- Hives, red spots, or swelling on your skin
- Anxiety
Peanut allergy and anaphylaxis symptoms
Sometimes, peanut allergies trigger a very serious reaction called anaphylaxis. This can happen even if you’ve had only mild reactions before.
Some signs of anaphylaxis are:
- Your airways close up.
- You notice swelling in your lips, tongue, or throat.
- Your blood pressure drops to dangerous levels.
- Your pulse is extremely fast.
- You feel dizzy or pass out.
Anaphylaxis is a medical emergency. You’ll need immediate treatment and a visit to the emergency room. If you or someone you're with has symptoms of anaphylaxis, use an epinephrine auto-injector pen right away and call 911.
Peanut Allergy Diagnosis
To diagnose a peanut allergy, your doctor will first ask about your symptoms and medical history. Then, they may suggest a physical exam along with:
- A food and symptoms diary. You may track what you eat, your symptoms, and the medicines you take.
- A skin test. This can be used to diagnose a peanut allergy and rule out other types of allergies. A tiny amount of peanut extract is placed on the skin of your arm or back. Then, a doctor or nurse pricks your skin with a needle. If you’re allergic, a reaction will show up as a raised bump or rash.
- A blood test. A blood test looks for IgE antibodies in your blood, which are a sign of an allergic reaction.
- An oral food challenge. You'll eat very small amounts of peanuts while in your doctor's office, with medication on hand to treat you in case of a reaction. The amount of peanuts you eat will increase over time so the doctor can watch your response.
Peanut Allergy Treatment
It’s important to avoid peanuts as much as possible when you have a peanut allergy. If you do come in contact with them, here are some medicines that can help:
- Epinephrine auto-injector (Adrenaclick, Auvi-Q, EpiPen, Symjepi). This prescription medicine can save your life. It comes in an easy-to-use container that even children can learn to use. Your doctor will tell you when and how to inject it. People close to you should also know how to use it. You should have two auto-injectors in case your reaction is very serious. After you use an auto-injector, always go to the emergency room because more symptoms could crop up.
- Antihistamines. These medicines can treat mild allergy symptoms. If you have a serious reaction, use antihistamines after you take an epinephrine shot.
- Corticosteroids. They can help with the swelling that a reaction can cause.
Oral immunotherapy for peanut allergy
In oral immunotherapy, an allergist gives you very small doses of peanuts that are gradually increased over time. This can help train your immune system to stay calm around allergy triggers. It can't stop a reaction, but it may lessen your odds for serious reactions in case of accidental exposure.
The FDA has approved peanut allergen powder (Palforzia) for oral immunotherapy in children ages 4-17.
Oral immunotherapy isn’t a cure. You'll still need to avoid peanuts, and you should still should carry two epinephrine auto-injectors at all times.
Antibody treatment
The antibody treatment omalizumab (Xolair) is given as a shot. It binds to the IgE proteins in your blood that prompt allergic reactions. This makes your immune system less reactive to allergy triggers.
Some studies have found Xolair can lower your risk of food allergy reactions and protect you from accidental peanut exposure. Like Palforzia, Xolair is not meant to be used in place of emergency auto-injector treatments.
Living With a Peanut Allergy
Living with a peanut allergy means staying away from peanuts, which can be tricky.
For one thing, you'll need to get good at reading food labels. U.S. law requires all packaged foods sold in this country to say whether they contain peanuts.
Even if they don't contain peanuts, foods that come into contact with them during processing can be dangerous. This is called cross contamination. The label will tell you if this is a possibility. It might say something like “made in a factory that uses nut ingredients.” Restaurant foods aren't required to have this labeling.
If you live with a peanut allergy:
- Always ask about ingredients in food you eat at restaurants and parties. If you’re unsure, don’t risk it.
- Be prepared in case you have a reaction. Always carry your epinephrine auto-injector and a spare.
- In case of serious allergy, wear medical alert jewelry to inform others about your peanut allergy in case of emergency.
- Be careful of cross contamination from utensils when eating from a buffet or sharing a kitchen with others.
Tips for parents of kids with a peanut allergy
To help protect a child with a peanut allergy:
- Teach them to read food labels.
- Let friends, family members, and the staff at their school know they have a peanut allergy.
- At school, request a separate eating space that’s far away from areas where peanuts are allowed.
- Make sure they always have two epinephrine auto-injectors with them.
- Pack them a lunch or snack if you’re unsure about what’s in the food at a restaurant or gathering.
- Have a written allergy action plan that details what should happen if your child has an allergic reaction. Give teachers, coaches, friends, and family members a copy of this plan.
- Teach your child never to share snacks or treats.
- Have them wear a medical alert bracelet or necklace.
Foods that often have peanuts
Some foods that may contain peanuts include:
- Mixed nuts
- Cookies, pastries, and other baked goods
- Ice cream and frozen yogurt
- Energy bars
- Cereal
- Granola
- Crackers
- Grain bread
- Egg rolls
- African, Mexican, Chinese, Thai, Vietnamese, and other ethnic dishes
- Chili
- Spaghetti sauce
- Enchilada sauce
- Salad dressings
- Marzipan (candy made of nuts, sugar, and egg whites)
- Nougat
- Hydroloyzed vegetable and plant protein in imported products
- Natural and artificial flavorings
- Nut butters like cashew and almond butter
Many people who are allergic to peanuts can safely eat refined peanut oil but should avoid the unrefined type. Ask your allergist whether any peanut oil is safe for you. Peanut oil is sometimes listed as “arachis oil” on food ingredient lists.
Other things that can trigger a peanut allergy
Some foods and products aren't covered by the U.S. allergen labeling law. This means they could contain peanuts or be made in a factory with peanuts but don't say so on the label.
Here are some items to look out for:
- Cosmetic and personal care items
- Prescription and over-the-counter medicines
- Toys whose stuffing could include peanut shells
- Foods with kosher labeling
- Pet food, treats, and supplies
- Alcohol and tobacco products
Peanut Allergy Complications
Anaphylaxis is the complication most people worry about when it comes to peanut allergies. It can happen seconds or minutes after you’ve been exposed to peanuts. It might start with symptoms that look like those of a milder reaction, but get worse in a hurry.
Basically, your body goes into shock. Your immune system sends out a blast of chemicals. This causes your blood pressure to quickly drop and your pulse to weaken. You might have trouble breathing or pass out.
You need epinephrine right away. Call 911 if you don’t have epinephrine on hand. Without proper treatment, anaphylaxis can be deadly.
Peanut Allergy Prevention
There may be a few ways to help prevent peanut allergies. For starters, you can give your kids peanuts when they’re young.
Research has found 17% of babies who don’t eat peanuts develop a peanut allergy by age 5. But only 3% who eat peanuts have allergies by the time they turn 5.
Newer guidelines from the National Institute for Allergy and Infectious Diseases (NIAID) say parents should give most babies foods that contain peanuts when they start solid foods. This is usually when the baby is about 4 to 6 months old. This recommendation applies to:
- Low-risk babies, those who don’t have eczema or egg allergies
- Moderate-risk babies, those with mild to moderate eczema who have already started solid foods
The NIAID notes that high-risk babies should have a blood or skin-prick test before they eat food with peanuts. High-risk means they have a history of serious eczema or an egg allergy. The test results can help doctors determine if it’s OK for the baby to have peanuts.
If doctors decide that peanuts are safe, guidelines suggest babies should eat 2 grams of peanut protein, three times a week. That’s the same as about 2 teaspoons of peanut butter. Babies should never be given whole peanuts, as they can choke on them.
Takeaways
When you have a peanut allergy, your body’s immune system reacts to peanuts as though they're dangerous. This causes reactions that can range from mild to life-threatening. People with peanut allergies must avoid peanuts. Treatments like oral immunotherapy and antibody treatment can help reduce the risk of serious reactions, but they're not a cure.
Peanut Allergy FAQs
What is a level 4 peanut allergy?
A level 4 peanut allergy means it's labeled “strongly positive” on the Peanut Institute’s allergy rating scale. The rating is assigned based on the level of IgE antibodies found in your blood during testing.
Here are all the peanut allergy levels:
- Class 0: Negative
- Class 0/1: Borderline
- Class 1: Equivocal
- Class 2: Positive
- Class 3: Positive
- Class 4: Strongly positive
- Class 5: Strongly positive
- Class 6: Strongly positive
How to cure peanut allergy?
There’s no cure for peanut allergy. But about 20% of people outgrow it. Others become less sensitive to peanuts over time. Also, newer treatments, like oral immunotherapy, can help you better tolerate peanuts. This may protect you from an accidental bite of a food that contains peanut.
What else am I allergic to if I'm allergic to peanuts?
You may or may not have other food allergies. People with peanut allergies are often also allergic to:
- Tree nuts, like almonds, Brazil nuts, hazelnuts, macadamia nuts, walnuts, cashews, pecans, and pistachios
- Lupine, which is another legume
