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November 18, 2014

Sulfa vs Sulfate vs Sulfur vs Sulfite Allergy

Having a "sulfa" allergy is quite common... What is uncommon is understanding that being "sulfa" allergic does not necessarily mean that one is also allergic to sulfates, sulfur, and sulfites. Also, when a patient states that have a sulfa allergy, they typically mean they have a "sulfonamide" allergy.

Why is this understanding of significance? It's because there is confusion whether a patient with a sulfa allergy can take sulfate containing medications safely. In the ENT world, that commonly means whether a patient can take cortisporin antibiotic ear drops which contains neomycin sulfate, polymyxin B sulfate, and hydrocortisone 10 mg (1%).

The answer is YES... a patient with a sulfa (sulfonamide) drug allergy can safely take drugs containing sulfate which is a completely different unrelated compound. They are NOT the same thing.

For that matter, sulfa allergic individuals should not be considered to be allergic to sulfur and sulfite containing substances either. Sulfite is a common preservative and can be found in small amounts in many fruits and vegetables (see below).

Sulfate allergy does not exist as far as I know, but it can act as a chemical irritant. Same goes for sulfur. Sulfite allergy does exist thru a non-immune mediated mechanism, but is exceedingly rare.

Here's a list differentiating common sulfa, sulfate, sulfur, and sulfite containing substances:

Sulfa (Sulfonamide)
• Bactrim antibiotic
• Sulfacetamide antibiotic eye drops
• Sulfasalazine used to treat IBS
• Thiazide diuretics
• Lasix diuretic
• Gyburide and Glipizide medications for diabetes

Sulfate Containing Drugs/Substances
• Cortisporin ear drops
• Heparin
• Dextran
• Morphine
• Soaps and Detergents (sodium lauryl sulfate)

Sulfite Containing Substances
• Lettuce, avocados, mushrooms
• Grapes, lemon, lime
• Wine
• Peppers, onions, pickles

Sulfur Containing Substances
• Fertilizer

So to summarize, people who react to sulfites do not need to avoid sulfates or sulfur.

People who react to sulfa do not need to avoid sulfites, sulfates or sulfur.


Fauquier blog
Fauquier ENT

Dr. Christopher Chang is a private practice otolaryngology, head & neck surgeon specializing in the treatment of problems related to the ear, nose, and throat. Located in Warrenton, VA about 45 minutes west of Washington DC, he also provides inhalant allergy testing/treatment, hearing tests, and dispenses hearing aids. Google+ Christopher Chang, MD Bio


  1. I am allergic to sulfates; such as in shampoos, Neosporin, silvedene. even commercial aloe has sulfate in it, which burns like Hattie's! I use sulfate free shampoo and bar soap. bacitracin for burns and cuts.

    1. Absolutely concur. I told one allergist I was allergic to sulfates and was pooh poohed. He prescribed Elidel to treat my skin task. I used Elidel for two days. By the third day, I went from having a rash on 20% of my body to having a rash (and severe itching) on 60% of my body. Elidel has a sulfate base!!! Still haven't forgiven the bastard.

  2. I am also allergic to all things sulfur, sulfa, sulfate, sulfide, etc. It is in fact possible. I spent a mission trip in Arizona and the sulfur in the water caused me to break out in hives and I couldn't drink the water because it caused blisters in my mouth and throat. I also had an anaphylactic reaction to the actual mineral sulfur in a class one time. People always roll their eyes and say it's not possible, but it definitely is. My reaction to neosporin was so bad when I was little they thought I had a flesh eating disease. I can't take a bath in Epsom salts (magnesium sulfate) because it causes me to break out in a rash. I'm legitimately allergic to sulfur.


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