A food allergy occurs when the immune system has a negative reaction to a specific food. The body produces an allergic antibody to the food, even though it’s harmless. When the food is ingested, the body has an allergic response.

While often used interchangeably, food allergies aren’t the same as food intolerances, which mostly affect the digestive system.

According to the Food and Drug Administration (FDA), about 30,000 Americans are treated in the emergency room each year for severe food allergies. About 150 to 200 Americans die each year due to their allergic food reactions.

Mustard allergies are beginning to get more attention.

Mustard seeds contain healthy minerals, such as iron, zinc, magnesium, phosphorus and calcium. They’re also a source of omega-3 fatty acids and have antioxidant properties. Historical naturopathic uses include relieving muscle and arthritic pain.

While mustard can have health benefits, some people develop an allergic reaction to mustard. The reaction can be serious.

Mustard is one of the . The primary allergen in yellow mustard is “Sin a 1.” The enzymes don’t break down much in the digestive tract, and the allergen is present even if the mustard is cooked in food. The major allergen in brown mustard is “Bra j 1.”

Anyone can develop a mustard allergy. It’s most common in the United Kingdom, Canada, and India — the countries that use the spice the most.

Many people with mustard allergies are also allergic to rapeseed. Some are also allergic to other products in the Brassicaceae family, including broccoli, cabbage, Brussels sprouts, cauliflower, turnips, and canola.

Mustard allergies are among the most severe food allergies. Ingesting it can cause a rise in histamine, and even anaphylactic shock.

The most common symptoms of mustard allergy are:

  • itching, hives, or skin rash
  • trouble breathing, wheezing, and nasal congestion
  • feeling dizzy, faint, or lightheaded
  • nausea, vomiting, diarrhea, and abdominal pain
  • swelling of the throat, face, tongue, and lips (this symptom requires emergency medical care)
Medical emergency

Severe cases of mustard allergy can cause anaphylaxis, which can be life-threatening. Symptoms of anaphylaxis include:

  • difficulty breathing due to swelling of the throat
  • fast, irregular pulse
  • shock and a drop in blood pressure
  • loss of consciousness

It’s not always easy to know where mustard might be lurking. You might think you only have to avoid putting it on common food items, like hot dogs and pretzels. But mustard is used as a spice in many seemingly innocuous products.

Avoid mustard seeds, mustard powder, mustard greens, and prepared mustard. It’s also important to make sure the following foods don’t contain mustard:

  • chips and pretzels
  • barbecue sauce
  • ketchup
  • mayonnaise
  • fish sauce and fish paste
  • salad dressing
  • salads
  • pickles
  • processed and deli meats
  • sausage
  • soups, sauces, and stock
  • seasonings and flavorings

These are only some of the foods that may contain mustard. When shopping, check ingredients lists. When you eat out, ask the server if a dish has mustard in it.

If you think you have a mustard allergy, a doctor can run a test to make sure. However, sometimes a test won’t show an allergy even if it’s present.

If you go into anaphylactic shock, seek medical help right away. The shock can be fatal if it isn’t treated.

An allergist can run tests to determine whether you have a mustard allergy. They may use a skin prick test or a blood test. However, neither is always accurate.

A more accurate test is to eat a small amount of mustard and see what happens. Then, gradually increase the amount to see if you have a reaction. Perform this test only with a doctor present.

Wear a medical bracelet that mentions your food allergy, so strangers can help if you have a reaction. A doctor can also prescribe an auto-injector of epinephrine (EpiPen) to use on yourself if you have a reaction. Even if you have used the EpiPen, seek medical attention right away.

Mustard allergies are often serious. The symptoms are consistent with other food allergies. They include hives, nausea, and dizziness. A more serious symptom is anaphylactic shock, in which you may notice swelling in your throat, difficulty breathing, and loss of consciousness.

If you have a mustard allergy, see a doctor for treatment options. Allergic reactions can be treated with an EpiPen, followed by emergency care. The best way to avoid a reaction is to be aware of what you eat.