Nightshade Allergy

Medically reviewed by Suzanne Falck, MD, FACP on April 12, 2017Written by Neel Duggal

What is a nightshade allergy?

Nightshades, or Solanaceae, are a family that includes thousands of species of flowering plants. Many nightshades are commonly used in cooking throughout the world. They include:

  • bell peppers
  • eggplants
  • potatoes
  • tomatoes
  • chili pepper
  • cayenne pepper
  • paprika

Tobacco, the plant found in cigarettes, is another example. Huckleberries are a rare example of a sweet nightshade. Sweet potatoes and yams — which look and taste like potatoes — are not nightshades.

Most other nightshades are not edible and many are poisonous if eaten. They also vary a lot in their shape, size, structure, and color. However, all nightshades are genetically similar.

Because they are a common part of many diets, it is important to know how they may affect you. Keep reading to learn about nightshade allergies and intolerance.

What’s the difference between a food allergy and a food intolerance?

Some people may have a minor intolerance to nightshade plants. This is because they aren’t able to digest them fully. People with a food intolerance may experience gas, bloating, and diarrhea. In more extreme cases, they may experience fatigue and joint pain.

Allergies to nightshade plants are considered very rare. Allergies are caused by glycoalkaloids, a compound naturally produced by all nightshade plants. This is a natural pesticide that helps the plant fight against pathogens, such as bacteria. It can also stimulate an immune response in people.

Of all nightshades, people most often develop allergies to potatoes because they contain several other allergens in addition to glycoalkaloids. Eggplant allergies are quite rare. You may also have reactions to some of the spicy nightshades. However, this may be caused by their spiciness.

Nightshade allergy symptoms

Food allergy symptoms include:

  • itchiness or rash
  • nasal congestion
  • wheezing or difficulty breathing
  • nausea or vomiting

Call 911 or seek emergency treatment if you experience:

  • difficulty breathing
  • a swollen throat, or the feeling of a lump in your throat
  • dizziness, lightheadedness, or loss of consciousness

These are symptoms of anaphylaxis. Anaphylaxis can be life-threatening if not treated promptly.

Who is at risk for developing a nightshade allergy?

There is not a lot of research about nightshade allergies. However, there are a few general factors that put you at risk for allergy to any food:

  • family history of food allergies
  • other allergies
  • being of younger age, usually under 12
  • past food allergies
  • asthma- this often increases both risk of developing an allergy as well as severity of symptoms

How is a nightshade allergy diagnosed?

Document any symptoms you develop and keep track of any patterns you notice. Because nightshade allergies are uncommon, keep track of any meals that contain more common allergens. These include fish, dairy, nuts, eggs, and soy.

A doctor can perform a variety of tests to diagnose a specific allergy. This can include a skin-prick test, where you’re exposed to the allergen and monitored for a reaction. They may take also take a sample of your blood and look for antibodies.

What treatments should you expect?

You can use several treatment methods to treat nightshade allergies. They include the following:

Stop eating nightshade plants

If your tests show you are allergic to a specific nightshade or several of them, avoid or limit how much of them you eat. Some, such as potatoes, can be easily substituted with alternatives such as sweet potatoes. Others, such as tobacco, are unhealthy even if you have no inflammatory response.

Best foods to replace nightshade plants

  • Replace bell peppers with celery, radishes, or Swiss chard.
  • Replace potatoes with sweet potatoes, yams, or cauliflower.
  • Replace eggplants, with portabella or shitake mushrooms.
  • Replace cayenne and red pepper with cumin, white, and black pepper.
  • Replace huckleberries and goji berries with blueberries.
  • Replace tomato sauces with alternative sauces such as pesto, olive, and alfredo.
  • Replace tomato bases with umeboshi paste and tamarind concentrate.

Talk to your doctor about prescription allergy medications

Your doctor can prescribe a variety of allergy medications to help treat your symptoms. These can include:

  • antihistamines: These medications treat symptoms of allergic responses.
  • decongestants: These decrease mucus buildup.

Nasal sprays

Anticholinergic sprays are a good first step. Steroid nasal sprays are useful for more severe cases.

EpiPens

If you have a serious nightshade allergy, talk about getting an EpiPen with your doctor. EpiPens are filled with epinephrine and are used to counter the allergic reaction. EpiPens are not an alternative to medical treatment.

If you think you’re experiencing anaphylactic shock:

  • stay calm
  • follow the directions to use the EpiPen
  • call 911 or have someone drive you to the emergency room

What’s the outlook for a nightshade allergy?

Nightshades are a diverse class of flowering plants. In rare cases, people may develop intolerance or an allergic response when eating them. If you suspect you may be allergic to them, see your doctor for tests that can confirm that.

CMS Id: 119151