Sulfite Allergy Overview and Foods to Avoid

A food additive that can trigger asthma symptoms

Sulfites are food additives used to enhance flavor and preserve freshness. These sulfur-based compounds also occur naturally in foods. For instance, they're in fermented beverages and wines. They're also used to increase the shelf life of some medications.

If you're allergic to sulfites or you have a sulfite sensitivity, you may experience symptoms like wheezing and coughing or flushing and dizziness after eating or drinking something that contains sulfites. Reactions can range from mild to potentially life-threatening.  

This article looks at who's affected, causes of sulfite allergies, how they're diagnosed, where sulfites are found, and how to prevent and treat reactions.

What to Look For

Examples of sulfites include:

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

Watch for these on food labels.

Foods and Medications Containing Sulfites
Illustration by Joshua Seong. © Verywell, 2018. 

What Are Sulfites?

Sulfites are chemical compounds that have antimicrobial and color-preserving properties. They are added to foods for various reasons, including:

  • Reducing spoilage due to bacteria
  • Slowing the browning of fruit, vegetables, and seafood
  • Inhibiting growth of bacteria during fermentation of wines
  • Conditioning of dough in frozen pie and pizza crust
  • Bleaching effect for maraschino cherries and hominy

Sulfites used to be added to fresh foods in restaurants and grocery stores to prevent browning. An increase in reactions led the U.S. Food and Drug Administration (FDA) in 1986 to ban them in fresh foods, particularly on fresh lettuce in salad bars.

Labeling Requirements

The FDA now requires sulfites to be declared on the label of any food containing more than 10 parts per million (ppm). Foods containing less than that haven't been shown to cause symptoms, even in people allergic to sulfites.

Foods Containing Sulfites

Sulfites are found in many different foods. Some are naturally occurring, while others are added to foods as preservatives or flavor enhancers.

Greater than 100 ppm of sulfites

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

  • Bottled lemon juice (non-frozen)
  • Bottled lime juice (non-frozen)
  • Dried fruits (except for dark raisins and prunes)
  • Grape juices (white, white sparkling, pink sparkling, red sparkling)
  • Molasses
  • Pickled cocktail onions
  • Sauerkraut and its juice
  • Wine

Between 50 and 99.9 ppm of sulfites

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

  • Dried potatoes
  • Fruit toppings
  • Gravies/sauces
  • Maraschino cherries
  • Wine vinegar

Between 10 and 49.9 ppm of sulfites

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

  • Avocado dip/guacamole
  • Cheeses (various)
  • Ciders and cider vinegar
  • Clams (canned or jarred)
  • Clam chowder
  • Cordials (alcoholic)
  • Corn syrup
  • Cornbread/muffin mix
  • Cornstarch
  • Dehydrated vegetables
  • Fresh mushrooms
  • Hominy
  • Imported fruit juices and soft drinks
  • Imported jams and jellies
  • Imported sausages and meats
  • Maple syrup
  • Pectin
  • Pickled peppers
  • Pickles/relish
  • Potatoes (frozen)
  • Shrimp (fresh)

Less than 10 ppm of sulfites

These foods have very low sulfite levels and generally pose no risk even for people with sulfite allergy:

  • Beet sugar
  • Beer
  • Canned potatoes
  • Coconut
  • Cookies
  • Crackers
  • Fruit salad, freash
  • Frozen pizza and pie dough
  • Gelatin
  • Grapes
  • High fructose corn syrup
  • Jams and jellies, homemade
  • Malt vinegar
  • Soft drinks
  • Soup mix, dry

Medications Containing Sulfites

Sulfites are added to some medications for their antioxidant properties and to prevent discoloration. For example, they're in the EpiPen and Twinject (injectable epinephrine) to prevent browning.

However, epinephrine injections haven't been shown to cause allergic reactions in people with a sulfite allergy. Don't withhold an EpiPen in an emergency. It may save someone's life.

Some asthma inhalers contain sulfites. But they've been taken out of many asthma drugs due to safety concerns.

If you have a sulfite allergy, avoid medications containing sulfites except for injectable epinephrine.

Many medications contain sulfites.

Bronchodilator solutions for asthma

  • Adrenalin chloride 1:1000 concentration (epinephrine)
  • Bronkosol (isoetharine)
  • Isuprel (isuprel hydrochloride)

Topical eye drops

  • AK-Dex, Ocu-Dex (dexamethasone)
  • Bleph-10 (sulfacetamide sodium)
  • Pred-Forte (prednisolone acetate)
  • Pred-Mild (prednisolone)

Injectable medications

  • Adrenaline, Ana-Kit, EpiPen (epinephrine)
  • A-Hydrocort, Solu-Cortef (hydrocortisone-injectable)
  • Amikin (amikacin)
  • Aramine (metaraminol)
  • Celestone (betamethasone phosphate)
  • Compazine (prochlorperazine) 
  • Decadron (dexamethasone phosphate)
  • Demerol (meperidine)
  • Dopamine
  • Garamycin (gentamycin)
  • Isoetharine HCl
  • Isuprel (isoproterenol-injectable)
  • Levophed (norepinephrine)
  • Nebcin (tobramycin)
  • Novocaine (procaine)
  • Phenergan (promethazine) 
  • Solutions for total parenteral nutrition and dialysis
  • Thorazine (chlorpromazine) 
  • Xylocaine with epinephrine (lidocaine with epinephrine)

Symptoms of Sulfite Sensitivity

Even in large quantities, sulfites usually don't cause problems in people without allergies and asthma. But between 3% and 10% of people with asthma see their symptoms increase after sulfite exposure.

Asthma symptoms include:

  • Wheezing
  • Chest tightness
  • Coughing
  • Shortness of breath

Adults with severe or poorly controlled asthma tend to have the worst problems. Studies suggest some asthmatics have severe symptoms after eating sulfites or inhaling their fumes or vapors.

Severe allergic reactions like hives/swelling and anaphylaxis can occur because of sulfites. The sensitivity to them sometimes shows up in skin tests for allergies.

Other people have severe reactions to sulfite-containing medications. That includes intravenous (IV) drugs and inhaled medications. Reactions include:

  • Flushing
  • Hives
  • Drop in lung function

Sulfites don't appear to cause anaphylaxis in people with idiopathic (unknown cause) anaphylaxis, mastocytosis, or mast (immune) cell disorder.

What Causes Sulfite Sensitivity?

Experts don't fully understand why some people react badly to sulfites. Some people make allergic antibodies against them, while others don't.

The gasses sulfites generate might cause lung-muscle spasms in some asthmatics. The reaction could also be related to an inability to metabolize (break down and use) sulfites.

Diagnosis

Sulfite allergy rarely shows up in allergy skin tests. Typically, it's 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's trained and is experienced with the procedure.

Prevention and Treatment

If you have or suspect a sulfite allergy, avoid foods and medications that contain them. The FDA label mandate makes this fairly easy.

It's trickier in restaurants, though. They can't be used on fresh produce, but you may run into unlabeled sulfite-containing foods.

Sulfites in potatoes are a big concern. If you're allergic to sulfites, avoid all restaurant potato products except for baked potatoes with the skin left on.

If you have an allergic reaction to sulfites, be sure it's treated promptly and properly. Use a non-sulfite-containing inhaler or injectable epinephrine if necessary. If your allergy is severe, you should wear a MedicAlert bracelet.

Summary

Some people are allergic to sulfites. They're a common food and medication additive because they keep food fresh. They prevent discoloration in drugs. Sulfites have been removed from many asthma inhalers.

The cause of sulfite allergies is unknown. Sulfites may worsen asthma, especially if it's not well controlled. An allergy may be diagnosed based on symptoms or an oral challenge.

Labeling rules make it easy to spot sulfites in packaged foods. It's harder in restaurant foods. Some of the highest levels are in potato products so they're best avoided.

A Word From Verywell

Sulfite allergies are uncommon. They're mostly seen with severe asthma. If you have asthma, don't worry about avoiding sulfites unless you know of or suspect a sulfite allergy.

If you have a severe allergic reaction and don't know why, get immediate medical help. Then follow up with your primary healthcare provider. They may test you for allergies or send you to a specialist.

Frequently Asked Questions

  • What does a sulfite allergy look like?

    A sulfite allergy can make asthma symptoms worse. It can vary from mild wheezing to a life-threatening asthma attack.

    Less common reactions include:

    • Hives
    • Angioedema (swelling under the skin)
    • Abdominal pain
    • Diarrhea

    In some cases, it can lead to anaphylaxis, a life-threatening allergic reaction.

  • How do sulfites preserve foods?

    Sulfite, or sulfur dioxide, has anti-microbial properties. It kills yeast, bacteria, and molds and keeps them from reproducing. It keeps food from getting brown by preventing oxidation (a reaction to oxygen exposure).

8 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. Vally H, Misso NL. Adverse reactions to the sulphite additivesGastroenterol Hepatol Bed Bench. 2012;5(1):16–23.

  2. D'Amore T, Di Taranto A, Berardi G, et al. Sulfites in meat: occurrence, activity, toxicity, regulation, and detection. A comprehensive review. Compr Rev Food Sci Food Saf. 2020;19(5):2701-2720. doi:10.1111/1541-4337.12607

  3. Bold J. Considerations for the diagnosis and management of sulphite sensitivityGastroenterol Hepatol Bed Bench. 2012;5(1):3–6.

  4. Vally H, Misso NL, Madan V. Clinical effects of sulphite additives. Clin Exp Allergy. 2009;39(11):1643-51. doi:10.1111/j.1365-2222.2009.03362.x

  5. Miyata M, Schuster B, Schellenberg R. Sulfite-containing Canadian pharmaceutical products available in 1991. CMAJ. 1992;147(9):1333-8.

  6. Irwin SV, Fisher P, Graham E, Malek A, Robidoux A. Sulfites inhibit the growth of four species of beneficial gut bacteria at concentrations regarded as safe for foodPLoS One. 2017;12(10):e0186629. doi:10.1371/journal.pone.0186629

  7. Cleveland Clinic. Sulfite sensitivity.

  8. U.S. Department of Agriculture. Sulfur dioxide.

Additional Reading

By Daniel More, MD
Daniel 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.