Medically reviewed by Debra Rose Wilson, Ph.D., MSN, R.N., IBCLC, AHN-BC, CHT
Written by Danielle Dresden
Nut allergies are among the most common food allergies, and they include reactions to almonds, walnuts, and pecans. An allergy to peanuts, however, is not technically a nut allergy.
Many of the 1.2% of people in the United States who are allergic to peanuts may mistakenly believe that they have a nut allergy, but peanuts are not actually nuts — they are legumes, similar to black beans and lentils.
However, according to the American College of Allergy, Asthma & Immunology, 25–40% of people with peanut allergies are also allergic to at least one tree nut.
In this article, we look at the symptoms, causes, and treatment of nut allergies.
What is a nut allergy?
If a person has a nut allergy, their body will react badly to eating tree nuts. A person may be allergic to one type of nut or multiple types, though doctors usually recommend that people with one nut allergy also avoid other nuts. Tree nuts include:
- macadamia nuts
- Brazil nuts
- pine nuts
- lychee nuts
Nut allergies are widespread and may be becoming more common, especially in children. According to Food Allergy Research & Education, hospitalizations for nut allergies in children tripled between the late 1990s and the mid-2000s.
What are the symptoms?
Nut allergy symptoms usually develop rapidly after a person eats or has exposure to nuts.
Symptoms can range from a mild runny nose to the life threatening symptoms of anaphylaxis, which include throat swelling, shortness of breath, and shock.
The same person can have different nut allergy symptoms at different points in time.
People with a nut allergy may experience the following symptoms after exposure to some or all types of nut:
- stomach pain
- itching, particularly around the face and mouth
- puffy or runny eyes
- swelling lips
- a gravelly throat
- trouble breathing
- difficulty swallowing
- feeling faint
Anaphylaxis can be fatal without prompt treatment. People with severe nut allergy symptoms should speak with a healthcare professional about getting a prescription for an EpiPen — an auto-injector with epinephrine. This device will give them ready access to the treatment that they need.
All nut allergy symptoms are due to the immune system’s response to nut protein, but there can be differences in the antibodies that the immune system creates as part of this reaction.
The most common type of nut allergy, and the one most likely to lead to dangerous reactions such as anaphylaxis, occurs as a result of the activation of immunoglobulin E (IgE) in the body. Different components of the immune system are responsible for most other reactions, which tend to develop more slowly.
The third type of allergic reaction has an association with a combination of IgE and other immune system elements.
Some people with food allergies, for example, those who are allergic to milk, outgrow them over time. Peanut allergies are more common in children than adults, affecting 2.5% of children but only 1.2% of the total population of the U.S. However, in general, allergies to peanuts and tree nuts tend to be lifelong conditions.
What to avoid
People who are allergic to nuts should avoid eating all tree nuts, even if a healthcare professional has only diagnosed them as being allergic to one type. Experts advise people with tree nut allergies to avoid peanuts as well.
Nutmeg may resemble a nut, but it is not one, so it should be safe for people with nut allergies to consume.
The Food and Drug Administration (FDA) consider coconut to be a tree nut, but it is officially a fruit. Individuals who are allergic to nuts should check with a healthcare professional before adding coconut to their diet or using products containing coconut.
Nuts have many different uses, and they can crop up in a wide variety of foods, beverages, and nonedible products. To avoid nut allergy symptoms, people with allergies should exercise caution when consuming or using:
- baked goods
- Asian, African, and Indian cuisine
- prepared soups and chili
- packaged mixes
- skin lotions
- hair care products
- some alcoholic drinks
As with other allergic reactions, nut allergy symptoms occur as a result of the immune system responding to the proteins in nuts as though they were harmful substances.
Scientists do not know exactly why some people’s bodies react this way to nut proteins, but as food allergies tend to run in families, genetics seem to be a factor. Individuals with other allergies, such as hay fever, are also more likely to develop nut allergies.
The basic treatment plan for people with nut allergies involves:
- avoiding all tree nuts and peanuts, as well as products that contain them and products that have undergone processing in the same facilities as these foods
- recognizing nut allergy symptoms and taking prompt action if they develop
- taking antihistamines to address mild symptoms, such as itching or swelling, if they arise
- people with severe allergies should carry an auto-injector, such as an EpiPen, so that they can treat anaphylaxis immediately should it occur
- if a child has nut allergies, parents or caregivers should make sure that teachers, care providers, coaches, and parents of the child’s friends understand the severity of the child’s condition
People with nut allergies need to be vigilant about reading labels to make sure that nothing that they eat contains nuts or could have become contaminated with nuts during the production process.
“Nut-proofing” a household can reduce the risk of accidental exposure and onset of nut allergy symptoms. Cleaning surfaces with cleaning sprays or sanitizing wipes can remove peanut residue. Washing the hands with running water and soap after handling nuts can also reduce the risk of contamination.
Researchers are currently exploring a variety of techniques to help people with peanut allergies build up their tolerance to peanut exposure.
Nut allergies are one of the most common food allergies in the United States, and nut allergy symptoms can range from bothersome to life threatening.
Avoiding foods and products comprising nuts is the best way to prevent reactions. However, because tree nuts and peanuts are present in so many foods and products, and cross-contamination can develop in facilities where manufacturers process nuts, people need to be vigilant to avoid accidental exposure.