Can You All of a Sudden Be Allergic to Nuts?

You don't have to develop an allergic reaction to peanuts, nuts or tree nuts the first time you come into contact with or eat them. You can enjoy them several times, then over time, as your body builds its immune system response, you begin noticing the symptoms. Once you are diagnosed with a peanut allergy, lifelong avoidance is the best treatment; the immune system appears to recognize peanut proteins more easily, according to KidsHealth.

That peanut butter sandwich can be potentially deadly. (Image: Photodisc/Photodisc/Getty Images)

First Exposure

The first time you eat peanuts or nuts, even if you don't experience a noticeable allergic reaction, inside your body, your immune system is reacting to the proteins in preparation for the next time you eat peanuts or something made with peanuts. Shortly after you have eaten a handful of nuts, your immune system begins to make antibodies especially for the proteins in peanuts. These antibodies are called immunoglobulin, or IgE. The next time you eat peanuts, the antibodies are ready. They recognize the peanut protein and release several chemicals into your body. One chemical is histamine, which causes a definite allergic response.


After eating peanuts or a food prepared with a peanut ingredient, you begin breaking out in a red, itchy rash. This includes hives and eczema. The skin on your hands, neck, face and legs begins getting puffy. You may begin sneezing and your nose may become runny. If you have asthma, you experience an asthma attack, with wheezing and difficulty breathing. Your heart begins beating rapidly. You may develop stomach cramps, nausea, diarrhea and vomiting. These symptoms develop quickly, sometimes almost as soon as you have eaten peanuts or within two hours after you eat the nuts. Some allergic reactions may develop about four hours after eating peanuts, but this is rare. If your reaction is severe -- anaphylaxis -- your throat feels as if it's closing, you may have trouble swallowing and you develop a strong sense of doom. As your airways close, your voice changes.

Systems Affected

A peanut allergy affects your entire body from the inside out. Your skin is affected. Inside your respiratory system, you develop what feels like the classic allergy symptoms -- runny nose, sneezing, watery and itchy eyes. You may also cough. If your reaction is severe enough, your cardiovascular system gets pulled into the response; you may become lightheaded and pass out. Your gastrointestinal system is also affected. You develop stomach cramps, diarrhea, nausea and possibly vomiting. The severe reaction called anaphylaxis is life-threatening -- your blood pressure drops precipitously and you lose consciousness. Your airways swell, making it difficult to breathe.

Don't Forget Tree Nuts

Your allergy to peanuts can include tree nuts such as cashews and walnuts. An allergic reaction to a tree nut is similar -- itching, hives, eczema, gastrointestinal symptoms, sneezing, runny nose, possible asthma symptoms and fainting. As with a severe reaction to peanuts, if your reaction to a tree nut is severe enough, you can experience anaphylaxis.

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