What to Avoid If You Have a Sulfite Allergy

A food additive that can trigger asthma symptoms

Sulfites are chemicals found in certain foods that can cause allergy symptoms in some people, including wheezing, coughing, and flushing. These sulfur-based compounds occur naturally in foods like wine and molasses but are also added to food to enhance flavor or act as a preservative.

Sulfite allergies can range from mild to severe. On rare occasions, sulfites can even trigger a potentially life-threatening, whole-body allergic reaction known as anaphylaxis.

This article explains the cause of a sulfite allergy and offers a list of foods and medications that contain sulfites. It also explains how sulfite allergies are diagnosed and treated, including the signs and symptoms of a medical emergency.

A sulfite allergy, like all allergies, is the result of an abnormal immune response to an otherwise harmless substance (known as an allergen).

Sulfites are chemical compounds that are found naturally in some foods but are also manufactured for commercial use as a food preservative or flavor enhancer. An allergy to sulfites can happen to anyone but is most common in people living with asthma.

For reasons that are not entirely clear, some people have a hypersensitivity to sulfite. In these people, the immune system will respond to sulfites as if they were a threat, releasing a defensive protein called immunoglobulin E (IgE) into the bloodstream.

IgE, in turn, causes specialized immune cells, known as basophils and mast cells, to break open and flood the body with an inflammatory compound called histamine.

Histamine is the main compound that causes allergy symptoms. It does so by spurring inflammation in the skin and mucosal tissues of the respiratory and digestive tract. When this happens, blood vessels will dilate (widen) and release fluids into surrounding tissue, causing them to swell.

This cascade of events can cause asthma-like symptoms, ranging from mild to severe, including:

In severe cases, sulfite hypersensitivity can trigger symptoms of anaphylaxis, including:

Anaphylaxis requires immediate emergency care without exception. Symptoms tend to develop within 30 minutes of consuming sulfites. If not treated appropriately, anaphylaxis can lead to shock, coma, heart or respiratory failure, and death.

Sulfites are found in many foods. Some are naturally occurring, while others are added.

Sulfites used to be added to fresh foods in restaurants and grocery stores to prevent browning. An increase in allergic reactions led the U.S. Food and Drug Administration (FDA) to ban their use in fresh vegetables and fruits back in 1986.

The FDA now requires manufacturers to declare on product labels if their food contains more than 10 parts per million (ppm) of sulfites. (Foods containing less than 10 ppm haven't been shown to cause symptoms, even in people with known sulfite allergies.)

Foods with sulfite levels greater than 100 parts ppm are considered very high in sulfates. If you have a sulfite allergy, you should strictly avoid these:

These are considered moderate to high sulfite levels. If you have a sulfite allergy, you're advised to avoid these:

These foods contain low to moderate levels of sulfite but can still cause symptoms in people with severe sulfite allergy:

These foods have very low sulfite levels and pose little to no risk in people with sulfite allergy:

There are several different sulfites used as food additives in the United States, including:

If you have a sulfite allergy, check product labels to see if any of these are included.

Sulfites are sometimes added to medications as a preservative, but this doesn't necessarily mean that you should avoid the drugs. In cases like these, the benefits of the drug may outweigh the risks.

One such example is the EpiPen (epinephrine auto-injector) used to treat an anaphylactic reaction. Because an EpiPen can save a person's life, the risks of a sulfite allergy tend to pale by comparison.

If you have a known allergy to sulfites, speak to your healthcare provider about the possible risks of using any of the following inhaled, topical, or injected medications:

Sulfite allergy rarely shows up in allergy skin tests. It is diagnosed based on a history of bad reactions to sulfites.

To confirm the diagnosis, your allergist may have you perform an oral challenge. You'll ingest increasing amounts of sulfites while your lung function and vital signs are monitored. A significant drop in lung function confirms the sensitivity.

This test should only be done under the direct supervision of a healthcare provider who is trained and experienced with the procedure.

If you have (or suspect having) a sulfite allergy, the best form of treatment is to avoid foods and medications that contain them. The FDA label mandate makes this fairly easy.

If an allergy does occur, the treatment can vary based on how severe your hypersensitivity is. Some of the more common treatment options include:

If you have a history of anaphylaxis, always carry two EpiPens with you (in case one doesn't work or one dose is not enough). You should also wear a MedicAlert bracelet.

Some people are allergic to sulfites found in foods or used as food additives. This can cause asthma-like symptoms or, on rare occasions, a potentially life-threatening allergy known as anaphylaxis.

If you have a sulfite allergy, the best thing you can do is to avoid foods and certain medications that contain them. The FDA requires manufacturers to advise consumers if sulfites are higher than 10 parts per million (ppm).

Oral, inhaled, or injected medications can be used to treat a sulfite allergy, including antihistamines, oral steroids, rescue inhalers, and an EpiPen auto-injector.

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By Daniel More, MDDaniel More, MD, is a board-certified allergist and clinical immunologist. He is an assistant clinical professor at the University of California, San Francisco School of Medicine and currently practices at Central Coast Allergy and Asthma in Salinas, California.