Sulfa vs Sulfate vs Sulfur vs Sulfite 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:
• 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
• Soaps and Detergents (sodium lauryl sulfate)
Sulfite Containing Substances
• Lettuce, avocados, mushrooms
• Grapes, lemon, lime
• Peppers, onions, pickles
Sulfur Containing Substances
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.