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 Are Sulfites?
Sulfites are chemical compounds that have antimicrobial and color-preserving properties. They are added to foods for various reasons, including:
Sodium sulfiteSodium bisulfiteSodium metabisulfitePotassium bisulfitePotassium metabisulfiteSulfur dioxide
Watch for these on food labels.
Reducing spoilage due to bacteriaSlowing the browning of fruit, vegetables, and seafoodInhibiting growth of bacteria during fermentation of winesConditioning of dough in frozen pie and pizza crustBleaching 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.
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)MolassesPickled cocktail onionsSauerkraut and its juiceWine
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 potatoesFruit toppingsGravies/saucesMaraschino cherriesWine 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 sugarBeerCanned potatoesCoconutCookiesCrackersFruit salad, freashFrozen pizza and pie doughGelatinGrapesHigh fructose corn syrupJams and jellies, homemadeMalt vinegarSoft drinksSoup 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)DopamineGaramycin (gentamycin)Isoetharine HClIsuprel (isoproterenol-injectable)Levophed (norepinephrine)Nebcin (tobramycin)Novocaine (procaine)Phenergan (promethazine) Solutions for total parenteral nutrition and dialysisThorazine (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:
WheezingChest tightnessCoughingShortness 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.
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.
Less common reactions include:
HivesAngioedema (swelling under the skin)Abdominal painDiarrhea
In some cases, it can lead to anaphylaxis, a life-threatening allergic reaction.
