Although "sulfa" and "sulfite" sound similar, the two chemicals are unrelated. So you won't necessarily be allergic to the other just because you've had a reaction to one.
Sulfiteare chemicals commonly used as preservatives and antioxidants in food (to prevent browning and spoilage). TOsulfonic acidAllergy refers to an allergy to drugs that contain sulfonamides (also called sulfur-based drugs). These drugs have a sulfonamide group in their chemical structure.
This article explains where sulfas and sulfites are found and what to avoid if you are sensitive to sulfas or sulfites.
Allergy to unfortunately sulfate
ASulfa AllergyIt is an allergy to drugs that have a sulfonamide group as part of their chemical structure. These can be antibiotics, diuretics (water tablets), eye drops, topical creams, and other types of medication.
Sulfa-based antibiotics are commonly used to treat skin, hospital-acquired, and fungal infections. Some researchers estimate that sulfa allergies affect up to 8% of people taking these drugs worldwide.
Symptoms of a sulfa reaction
Sulfa allergies can show up in many ways, including a skin rash. Your reaction can range from mild to severe.
Regardless of how your allergies are occurring, you should see a doctor right away. An initially mild allergic reaction can progress quicklyAnaphylaxis, a serious and life-threatening reaction that requires emergency medical treatment.
A common, flat, red rash, also known asmaculopapularA rash is the most common symptom of a sulfa allergy, but you may also have the following symptoms:
- Generalized itching (itching)
- Urticaria (Urticaria), in which the red, itchy rash develops into raised wheals with a well-defined border
- swelling of the face, lips, hands, or tongue (Angioedema)
- Difficulty breathing, which in severe cases can be a sign of anaphylaxis.
- Stevens-Johnson-SyndromÖtoxic epidermal necrolysis, a blistering rash that destroys the top layers of skin and mucous membranes
Sun exposure can trigger or worsen your rash. Finding some shade and cooling off with ice are some of the first steps you can take when you get a mild rash.
List of drugs containing sulfate
In some people, sulfonamides can cause the body to release themHistamine, which causes a systemic (body-wide) inflammatory response that can affect one or more organs.
If you have a sulfa allergy, you should avoid antibiotics such as Bactrim or Septra (TMP/SMX, trimethoprim-sulfamethoxazole). Trimethoprim-sulfamethoxazole is the most widely used sulfa antibiotic. Since sulfamethoxazole is often combined with trimethoprim, any antibiotic containing trimethoprim should be avoided.
Other sulfa-based antibiotics include sulfadiazine, Silvadene (silver sulfadiazine), AVC vaginal (sulfanilamide), and sulfacetamide (found in prescription and over-the-counter topical products).
Non-antimicrobial agents containing sulfonamides encompass several classes of drugs. Some health professionals avoid prescribing them to people with an allergy to antibiotics containing sulfonamides. However, research has shown that a reaction is unlikely, so they can be prescribed.These drugs include.
- Antivirals against human immunodeficiency virus (HIV), such asprotease inhibitorsAgenerase (Amprenavir), Prezista (Darunavir), Lexiva (Fosamprenavir) and Aptivus (Tipranavir)
- Carbonic anhydrase inhibitors such asDiamox (Acetazolamida)used for treatmentGlaucoma(increased intraocular pressure),Epilepsyand altitude sickness
- Hand diuretics (used to control heart failure), such asBumex (Bumetanid)miLasix (Furosemid)
- sulfonylureas (used to control diabetes), such asGlucotrol (Glipizida)miDiabetes (gliburida)
- COX-2 inhibitors (an anti-inflammatory) such asCelebrex (Celecoxibe)
- triptans (used to treat migraines), such asImitrex (Sumatriptano)
- Thiazide diuretics (used to control heart failure and high blood pressure) such as Thalidone (chlortalidone) and HydroDiuril (hydrochlorothiazide)
- Azulfidina (Sulfasalazin)(used for inflammatory bowel diseases etc.)rheumatoide Arthritis)
An adverse reaction to sulphites can cause true allergy (where the immune system responds to their presence) or sensitivity (where symptoms appear but no immune system response).
Symptoms of a sulfite reaction
One truthSulfitallergieit usually leads to asthma-like symptoms. Sulphite sensitivity can cause gastrointestinal symptoms. The following symptoms may occur with an immune reaction to sulfite:
- Difficulty breathing (often associated withasthma exacerbations)
- Allergic rhinitis(runny nose, sneezing, watery eyes)
- Urticaria (Hives)
If you ingest sulfite in processed foods or white wine, you may experience gastrointestinal symptoms such as gas, diarrhea, indigestion, and vomiting, indicating sulfite sensitivity, especially in the absence of upper respiratory symptoms.
Food and drinks containing sulphites
If you are a wine or beer drinker, chances are you have consumed some sulphites in your life as they are naturally found in fermented foods. Many foods, especially processed foods, contain sulphites to keep them from spoiling.
Common foods that contain sulfites are:
- dried fruit
- Condiments such as ketchup, mustard and mayonnaise
- frozen shrimp
- fried porridge
- Bottled lemon or lime juice
- fruit juices and imported soft drinks
- Frozen pizza and pie crust
- Canned fruits and vegetables and frozen foods
It is important to note that all of the above foods should be avoided if you have an allergy, but white wine and nuts in particular should be avoided as they contain more sulphites.
The Food and Drug Administration (FDA) requires sulphites to be listed on food labels if the food contains more than 10 parts per million (ppm).Examples of sulfites are:
- sodium sulfite
- sodium metabisulfite
- Potassium bisulphite
- potassium metabisulfite
- sulfur dioxide
Sulfa versus sulphites
Sulphites are commonly added to foods to preserve them and are naturally present in fermented foods. If you are sensitive or allergic to sulfites, check food labels and ask restaurant staff about food ingredients. The FDA banned sulfites in fresh fruits and vegetables in 1986.
In particular, sulfite is added to drugs such as epinephrine, thorazine (chlorpromazine), and dopamine to prevent discoloration. An injection of epinephrine (such asEpiPen) should even be given to a person with a sulfite allergy if they are suffering from anaphylaxis as it is necessary to save their life.
Sulfa is mainly found in medicines and dietary supplements. There is no test for sulfa allergy, so people often find they have an allergy after an adverse medical reaction to a drug, dietary supplement, or personal care product.
Reactions to sulfa and sulfite drugs develop within one to 48 hours after ingestion of the substance. Both usually subside within two weeks of stopping the pathogen. Stopping soon after the onset of an itchy rash or hives may resolve your symptoms. Antihistamines and corticosteroids can help.
No treatment will prevent reactions to sulphites, so triggering substances should be avoided. Some health professionals may try a sulfa allergy desensitization program, prescribing small but increasing doses to improve tolerance.
Make sure you report any known or suspected allergies to a healthcare professional so they can avoid prescribing medications that could trigger a reaction.
Sulfa and sulfite drug allergies sound similar in name, but they're two different things. Sulfites are commonly found in packaged foods and wines, while sulfa is found in pharmaceuticals (mainly antibiotics) and dietary supplements.
Sulphite allergies often present with asthma-like symptoms such as wheezing and shortness of breath, while sulphate allergies are often accompanied by a skin rash. Contact a doctor if you have a reaction. Get emergency medical attention if you have a severe reaction.
Knowing what triggers the allergy or sensitivity and avoiding it is key to preventing future reactions. Report allergies to your doctor. Check food labels if you have a reaction to sulphites.
A word from Verywell
Sulfites are preservatives that may seem impossible to avoid if you have a sulfite allergy or sensitivity. This can be frustrating, but eating fresh fruits and vegetables will limit your sulfite intake to a negligible amount.
Sulfa allergies usually appear shortly after taking the medication. Always tell a doctor about a known sulfa allergy.
If you have a sulfa or sulfite allergy, tell your family and friends and explain the difference between the two so they can help you avoid substances (such as sulfa drugs and foods for sulfite allergies) that may cause allergies can cause you an allergy. .
frequently asked questions
What medications are safe for someone with a sulphate allergy?(Video) SULFUR: The Most Important Element in Detoxification – Dr.Berg
There are many non-sulfate antibiotics that you can take in place of sulfa-containing antimicrobials. In the case of urinary tract infections, e.gZypern (Ciprofloxacin). Which antibiotic is best for you depends on the bacteria involved and your allergy profile.
Learn more:Facts about antibiotics
Can you do a sulfa allergy test?
No. There are no tests to diagnose a sulphate allergy. The diagnosis is made based on your symptoms, physical exam, and medical history.
Learn more:How are allergies diagnosed?
How is a sulfite allergy treated?
The best way to avoid an adverse immune response from a sulfite is to avoid that substance entirely. Sulphite allergies cannot be cured.
For people with sulfite-sensitive asthma, use aAsthma-InhalerIt can help with symptoms that affect breathing.Oral steroids may be required. In the case of skin reactions, antihistamines and a cortisone cream can help against the rash. If you have symptoms of anaphylaxis, seek emergency medical attention.
Verywell Health uses only quality sources, including peer-reviewed studies, to back up the facts in our articles. read ourspublishing processfor more information about how we review our content and keep it accurate, reliable and trustworthy.
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Mechtler AG, Chamarro-Pareja N., Carillo-Martin I., Haehn D., Gonzalez-Estrada A.Six-step trimethoprim-sulfamethoxazole desensitization protocol in HIV-negative patients with self-reported sulfa allergy: a one-centre experience.J Allergy Clinic Immunol.2019:143(2):AB33. doi:10.1016/j.jaci.2018.12.102
American College of Allergy, Asthma and Immunology.drug allergy.
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VonShamard Charles, MD, MPH
Shamard Charles, MD, MPH is a physician and public health journalist. She has held positions at major news networks such as NBC, covering public health policy, public health initiatives, diversity in medicine and new developments in health research and medical treatments.
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