Allergies to Nightshade Vegetables

A basket of potatoes, peppers, tomatoes and other vegetables.
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Nightshade vegetables are a group of vegetables containing about 85 genera and over 2,000 various species. The most commonly known nightshade vegetables include potatoes, peppers and tomatoes. An allergic reaction to nightshade vegetables is considered uncommon, according to Medline Plus. Most food allergies are caused by nuts, milk, eggs, soy, wheat, fish and peanuts. If you suspect that you have an allergy to nightshade vegetables, talk with your doctor for further testing.

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An allergy is caused by a malfunction in the immune system. Your body mistakes the proteins from the nightshade vegetables as a harmful substance and attempts to fight them off. Within minutes of consuming a nightshade vegetable, your body begins to create specific antibodies that are engineered to destroy the nightshade vegetable proteins. The introduction of the IgE antibodies into the blood causes the production of histamine in soft tissue throughout the body, mainly affecting the lungs, skin and nasal passages.


A nightshade sensitivity, on the other hand, is when you are unable to digest nightshades fully. You should stay away from these nightshade vegetables if you have a sensitivity.

Rhinitis and Asthma Symptoms

Common symptoms that can occur within minutes of eating nightshade vegetables are rhinitis and asthma, according to Medline Plus. Rhinitis is the inflammation in the sinuses, the eyes and throat. You can develop itchy, watery eyes, nasal congestion, a runny nose, postnasal drip, a sore throat and sneezing fits as a result of increased histamine in these areas. The lungs can also swell, leading to shortness of breath, chest pain and wheezing. Wheezing is a high-pitched sound made by the opening of the throat being blocked by inflammation.


Digestive Symptoms

Digestive symptoms are common with any food allergy. The intestinal tract can become inflamed from histamine, leading to vomiting, nausea, diarrhea, stomach cramping and abdominal pain. If you develop mucus or blood in your stool, talk with your doctor immediately. Once the nightshade vegetables are eliminated from the body, symptoms will subside. If they persist, another medical condition may need to be addressed.


The best treatment for an allergy to nightshade vegetables is to eliminate them from your diet. If you accidentally consume nightshade vegetables, use an antihistamine to treat minor allergy symptoms, such as sneezing, watery eyes and hives. Over-the-counter digestive medications will have no effect on digestive symptoms until the proteins pass.



As with any food allergy, anaphylactic shock may occur. Anaphylaxis is a rare, severe allergic reaction that affects the entire body. Your blood pressure will suddenly drop, you will become dizzy, your throat may close and you may break out in hives. Call 911 immediately. An injection of epinephrine may be required to treat the symptoms.