Can You All of a Sudden Be Allergic to Nuts?

An allergy to nuts means you're unable to consume tree nuts like almonds, walnuts, cashews, pine nuts and Brazil nuts. People usually develop food allergies as children, but can also develop them as adults. It is not certain why the sudden onset of food allergies in adults occurs.

Read more: The Worst "Health" Foods

Most people develop allergies as children. If you have a nut allergy as a child, you may even grow out of it.

However, according to the American College of Allergy, Asthma and Immunology and the Mayo Clinic, it's also possible to develop a food allergy as an adult. The sudden onset of food allergies in adults can occur even when a person has been eating that food for their entire lives. Once you become allergic to something as an adult, it's likely to always cause you issues.

That being said, adult food allergies are rare. Harvard Health Publishing says that only 4 percent of adults are allergic to food products.

If you suspect a sudden walnut allergy or other tree nut allergy, you are likely to experience symptoms like:

• Gastrointestinal symptoms, including stomach pain, cramps, nausea, vomiting and diarrhea.

• Feeling like your throat is closing up. This may make you feel like you are having problems swallowing or shortness of breath.

• Itchy mouth, throat, eyes or skin.

• Tingling or numbness.

• Runny or blocked nose.

• Anaphylaxis. This is the most dangerous symptom —

  it can be life-threatening and has the potential to send the body into shock.

Keep in mind that a sudden walnut allergy may also mean that you'll have a sudden allergy to almonds and other tree nuts. You may also have a sudden peanut allergy, despite the fact that peanuts are a legume rather than a tree nut. You might even develop an allergy to pollen or something else that is seemingly unrelated.

Read more: Symptoms of a Peanut Butter Allergy

This is due to cross-reactivity. According to a June 2015 study in the World Journal of Methodology, cross-reactivity occurs when your immune system has a response to similar allergenic molecules.

Closely related species, like different nuts within the tree nut family, can consequently induce the same type of allergic response. Cross-reactivity can also occur when two unrelated species share a similar protein structure. For instance, 70 percent of people who are allergic to birch pollen are also allergic to nuts, especially hazelnuts.

Because tree nut allergies can be very serious and even deadly, the American College of Allergy, Asthma and Immunology, World Journal of Methodology and the Mayo Clinic all recommend avoiding these foods if you've discovered you're allergic to them. If you suspect a sudden tree nut allergy, you should talk to your doctor.

If you've developed a sudden walnut allergy but aren't sure if you're allergic to other tree nuts, your allergist can help you determine which nuts you can safely eat or need to avoid. The doctor will also be able to help you determine any cross-reactive allergies you may have.

Talking with an allergist about your sudden nut allergy will help you determine how serious it is. If your allergy is particularly severe, it may be advisable to carry around an epinephrine autoinjector in case you accidentally ingest a product with nuts in it.