Mustard Allergy

What is a mustard allergy?

A mustard allergy is a type of food allergy. It causes your immune system to overreact when you eat mustard products. Although mustard allergy is rare overall, it’s still thought to be among the most common spice allergies. It affects children and adults.

What is mustard?

The mustard plant belongs to the Brassicaceae family, which includes broccoli, Brussels sprouts and cauliflower. (It’s OK to eat these vegetables if you have a mustard allergy, but you shouldn’t eat their seeds.)

Food manufacturers and home cooks use whole mustard seeds to marinate, roast and pickle foods. Ground, cracked and whole seeds make table mustard (the popular hot dog condiment). Mustard powder is often added to soups, sauces and salad dressings. And some people enjoy eating the plant’s peppery-tasting leaves called mustard greens.

What are food allergies?

A food allergy occurs when your body’s immune system mistakes certain substances in foods as harmful. White blood cells in your immune system start making antibodies (proteins) to protect your body against this perceived danger. This response triggers an allergic reaction (allergy) to the substance (allergen).

As a food allergy, mustard isn’t as common or well-known as peanut allergies and milk allergies. But people with mustard allergies can have serious — sometimes life-threatening — reactions.

How common is a mustard allergy?

In the U.S., food allergies affect about 16 million adults and 4 million children. Experts don’t know how many people are allergic to mustard. Some people might not recognize mild symptoms of a mustard allergy. Mustard allergies appear to be more common in countries like France where it’s a favorite condiment and food ingredient.

What causes mustard allergy?

Mustard is a harmless substance. But when you have a mustard allergy, your immune system reacts differently. It mistakenly sees certain proteins in mustard as dangerous and sends antibodies to destroy the harmless invaders. It’s this overreaction that causes allergic reactions. Experts aren’t sure why some people develop mustard allergies and other food allergies.

Who’s at risk for mustard allergy?

These factors increase your risk of a food allergy:

• Allergic rhinitis (hay fever).
• Asthma.
• Eczema.

What are mustard allergy symptoms?

People with mustard allergies who consume small amounts of mustard may not have severe symptoms. For this reason, some people aren’t aware they’re allergic to mustard.

Signs of a mustard allergy include:

• Abdominal pain.
• Diarrhea.
• Dizziness.
• Hives or skin rash.
• Nausea and vomiting.
• Swollen lips, tongue or face.
• Throat inflammation and difficulty swallowing.
• Wheezing or shortness of breath.

What are the complications of a mustard allergy?

Someone with a severe mustard allergy is at risk for anaphylaxis. This immune system response is immediate and severe. Some people go into anaphylactic shock, which causes dangerously low blood pressure and severe throat swelling.

Anaphylaxis can be life-threatening and requires prompt medical attention. People with severe mustard allergies should always have an epinephrine auto-injector with them in case they accidentally eat foods with mustard.

What healthcare providers diagnose and treat mustard allergies?

For diagnosis and treatment, you’ll see an allergist. These doctors diagnose and treat all types of allergies, as well as asthma. Allergists are also immunologists, which means they may also treat immune system disorders and autoimmune diseases.

How do healthcare providers diagnose a mustard allergy?

Your healthcare provider may diagnose a mustard allergy based on your family history, medical history and symptoms.

You may also get allergy testing, like:

• Skin prick (scratch) test: Your provider uses a thin needle to scratch the surface of the skin with tiny amounts of different allergens underneath the outer layer of your skin (epidermis). If you’re allergic to a substance, you may develop itchy skin, a rash or another reaction.
• Blood test: An allergy blood test measures levels of antibodies in your blood. A high number of allergy antibodies can indicate a potential food allergy. However, these tests can give false positive results more than half of the time. This means the test may indicate you have a particular allergy when you don’t.
• Oral food challenge: In rare instances, your provider may have you eat a small amount of mustard. You gradually consume larger amounts while your provider notes your reactions. You should only do a food challenge in a medical setting where emergency help is available.

How is mustard allergy treated?

There isn’t a treatment or cure for mustard allergies. Over-the-counter (OTC) or prescription antihistamines can ease symptoms like hives and wheezing. If you’re at risk for anaphylaxis, you should always have epinephrine medications with you.

How can you manage a mustard allergy?

People with mustard allergies shouldn’t eat mustard or foods made with mustard. To limit the risk of accidental exposure to mustard (cross-contamination), prepare your food in a separate area of your kitchen or ask a restaurant to do the same.

How can you prevent a mustard allergy?

You can’t prevent a mustard allergy. But you can limit your risk of mustard exposure and experiencing an allergic reaction if you have a mustard allergy.

The U.S. Food and Drug Administration (FDA) requires food and drink labels to list all ingredients. You should carefully read all ingredients on food labels to check for mustard. A product’s ingredients may change at any time. You should read the ingredient list every time you buy a food item even if the product was mustard-free or “safe” in the past.

The Federal Food, Drug and Cosmetic Act requires food labels to clearly state if a product contains a major food allergen, like milk or eggs. Nine major food allergens cause most food allergies in the U.S. Because mustard isn’t one of them, food labels don’t usually include a “made with mustard” or “contains mustard” warning. You can’t always rely on sight, taste or smell to tell when there’s mustard in a food product.

If you’re traveling to Canada, Europe or Asia, you may see mustard warnings clearly stated on food labels. That’s because these regions consider mustard to be a major food allergen. Foods in these countries must state when mustard is present in a food.

What foods should you avoid if you have a mustard allergy?

Foods likely to have mustard or mustard seeds in them include:

• Baby food.
• Cold-pressed canola oil and rapeseed oil.
• Condiments, like ketchup, mayonnaise and barbecue sauce.
• Curries.
• Pickles and pickled foods.
• Pretzels and potato chips.
• Processed deli meats and sausages.
• Soups and salad dressings.

When should I call the doctor?

You should call your healthcare provider if you experience signs of an allergic reaction, like:

• Difficulty breathing.
• Facial or throat swelling.
• Hives or skin rash.
• Severe abdominal pain, diarrhea or vomiting.

What should I ask my provider?

You may want to ask your healthcare provider:

• Why did I develop a mustard allergy?
• What foods should I avoid?
• Am I, or my family members, at risk for other food allergies?
• Should my family members avoid mustard?
• Should I carry epinephrine medication with me?

What is mugwort-mustard allergy syndrome?

Mugwort-mustard allergy syndrome (MMAS) is a rare type of pollen food allergy syndrome (also called PFAS or oral allergy syndrome). People with MMAS react to mugwort (a plant) and mustard.

Some herbal teas, herbal medications and dietary supplements contain mugwort. You can also breathe in mugwort pollen grains as they float in the air.

MMAS occurs when your immune system views mugwort pollen and mustard proteins as similar. These cross-reacting allergens trigger symptoms, like an itchy mouth, scratchy throat and swollen lips or tongue. This type of oral allergy syndrome rarely causes anaphylaxis.

You’re more likely to develop MMAS if you:

• Are an older child, teen or adult with hay fever.
• Have allergic reactions to mugwort.
• Live in an area where mugwort grows, such as the Northeast, southern states, Washington and Oregon.

What’s the difference between mustard allergy and mustard intolerance?

Mustard allergy and mustard intolerance have different causes. They also affect different body systems:

• Mustard allergy affects your immune system. Symptoms, like breathing difficulties, tend to occur almost immediately after mustard exposure. In some instances, these symptoms are life-threatening.
• Mustard intolerance affects your digestive system. This type of food intolerance occurs when your digestive system can’t break down mustard. Mustard intolerance symptoms like indigestion (dyspepsia) occur hours after exposure as the food moves through your digestive tract. While food intolerance symptoms can be uncomfortable, they’re not life-threatening.

Why does mustard make me sweat?

Sweating when you eat hot or spicy foods like mustard is common. There’s even a name for food-related sweating: gustatory syndrome or Frey’s syndrome.

Mustard seeds have a substance called sinigrin that also gives horseradish its kick. Crushing or grinding mustard seeds releases a fiery enzyme called myrosinase. When you mix crushed mustard seeds with cold water, it creates a spicy mustard oil. This powerful mustard oil in mustard products raises your body temperature. Your body sweats to cool down.