context: Sulfa drugs can treat a range of health problems from eye infections to rheumatoid arthritis ( RA). But if you get a rash or more serious reaction when you take one of these drugs, you may have a sulfa allergy. Sulfa drugs, also called sulfonamides, include antibiotics and other types of drugs. Allergies happen most often with antibiotics. Around 3% of people have some type of reaction to them. Tell your doctor right away if you think you're having a reaction to a sulfa drug. She'll decide whether to take you off the drug and how to treat your symptoms. If you're allergic to sulfa drugs, or any other medication, you may have one or more of these symptoms: Skin rash or hives Itching Breathing problems Swelling The reaction can also cause these serious skin reactions: Sulfonamide drug hypersensitivity syndrome: Rash, fever, and organ problems begin within 1 to 2 weeks after you start the drug. Drug eruption: Red or swollen, rounded patches form in 30 minutes to 8 hours. Stevens Johnson syndrome: This potentially life-threatening reaction causes skin to blister and peel off. Other reactions to sulfa drugs include headache, trouble sleeping, cloudy urine (crystalluria), and low blood counts. Rarely, a severe allergic reaction called anaphylaxis happens. Sulfa antibiotics have been widely used for more than 70 years. In fact, the first antibiotic was a sulfa drug introduced in 1936. Today, these drugs include burn creams, vaginal suppositories, and eye drops as well as medications for many types of infections. If you've had an allergic reaction to one sulfa antibiotic, you're probably allergic to all of them. Here are a few examples of common sulfa drugs that could cause problems: Sulfamethoxazole/trimethoprim ( Bactrim, Sulfatrim): a sulfa combination drug that can be taken in liquid or pill form for many types of infections Sulfacetamide ( BLEPH-10): drops for eye infections Sulfadiazine silver ( Silvadene): cream to prevent and treat burn infections Sulfasalazine ( Azulfidine): pills for rheumatoid arthritis and inflammatory bowel disease Even if you're allergic to antibiotics that have sulfa, you might be able to take some other types of sulfa drugs without a reaction. Ones that may be safe to take include: Glyburide ( Glynase, Diabeta), a drug for diabetes Celecoxib ( Celebrex), a nonsteroidal anti-inflammatory medicine ( NSAID) Sumatriptan ( Imitrex, Sumavel Dosepro, Zecuirty), a migraine drug Water pills, or diuretics, including furosemide ( Lasix) and hydrochlorothiazide ( Microzide) But be sure to tell your doctor if you have a sulfa allergy before taking any of these. A sulfa allergy sounds like a sulfite allergy, but they're very different. Sulfa drugs treat health conditions. Sulfites are preservatives used in many foods, drinks (especially wine), and medications. Sulfites can trigger asthma symptoms and on rare occasions can cause anaphylaxis. It's common for people who have asthma to be sensitive to sulfites. But it's unusual for other people. Sulfa drugs and sulfites are not related. Neither are their allergies. There's no need to give up dried fruit, wine, or other items that contain sulfites if you're sensitive to sulfa drugs.