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Asthma Health Center

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Asthma and Sulfite Allergies

Sulfites are a common additive in many foods and drugs. Sulfites also occur naturally in some foods.

Unfortunately, 5%-10% of people with asthma are also allergic to sulfites. An allergy is an increased sensitivity to a specific substance (called an allergen). The combination of asthma and sulfites can be dangerous. If you have asthma and sulfite allergy, eating foods or taking drugs that contain sulfites can even be life-threatening.

What Are Sulfites?

"Sulfites" is the general name for six specific substances:

  • Sulfur dioxide
  • Sodium sulfite
  • Sodium bisulfite
  • Sodium metabisulfite
  • Potassium bisulfite
  • Potassium metabisulfite

As additives, sulfites do many things:

  • They can prevent spoilage and preserve foods -- and certain beverages -- by preventing the growth of mold and bacteria, for example.
  • They can stop fruits, vegetables, and seafood from discoloring.
  • They can maintain the strength of common medications -- including some asthma drugs.

Sulfites may be added to foods and beverages such as:

  • Apple cider and other types of cider
  • Avocado dip
  • Beer and wine
  • Condiments, jams, gravies, and molasses
  • Dried fruits and vegetables
  • Fruit and vegetable juices
  • Peeled potatoes (including french fries)
  • Pickled meats and vegetables
  • Restaurant food and other prepared foods
  • Shrimp and shellfish

Sulfites may also occur naturally in foods such as:

  • Asparagus
  • Chives
  • Corn starch
  • Eggs
  • Fish, such as salmon and dried cod
  • Garlic
  • Leeks
  • Lettuce
  • Maple syrup
  • Onions
  • Soy
  • Tomatoes

According to federal law, sulfites cannot be added to foods that are intended to be eaten raw, such as fruits and vegetables. When they are used as a preservative in food preparation or processing, they must be listed as an ingredient.

Symptoms of a Sulfites Allergy

The severity of allergic reactions to sulfites can vary. Symptoms of a sulfite allergy include:

The combination of asthma and sulfites can be life-threatening because it can lead to anaphylactic shock. If this occurs, the entire body reacts severely to the allergen. The airways can swell shut, making it difficult to breathe. According to the American Academy of Asthma, Allergy and Immunology, as many as 5%-10% of sulfite reactions in people with asthma are fatal.

If you have signs of an allergic reaction to sulfites, get emergency help. In many cases, using your quick-relief inhaler can help control your reaction. If you have an epinephrine injection kit available, use it without hesitation, even if those symptoms do not appear to be allergy related. Using the pen as a precaution will not harm you and could save your life. Call 911 even after injecting yourself.

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