Being told that one is "sulfur allergic" commonly causes confusion, as many people wrongly assume that they will be allergic to multiple sulfur-containing medicines or sulfite preservatives. It is important to know that sulfur is an important building block of life, and that allergic reactions to sulfonamide (sometimes called "sulfur") antibiotics do not increase the likelihood that a person will also be allergic to sulfur powder, sulfite preservatives, or non-antibiotic sulfonamide medicines like some pain killers or diuretics ("water tablets"). Two new articles on these topics have just been released on the ASCIA website to try to clarify the differences between sulfite and sulfonamide allergies Sulfites are preservatives which are used in some drinks, foods and occasionally medications. They can cause allergy-like reactions (intolerances), asthma symptoms such as wheezing in those with underlying asthma, hay fever-like reactions, urticaria (hives) and very rarely, anaphylaxis (allergic shock). Sulfonamide antibiotics (such as Bactrim, Resprim, Septrin, Sulfadiazine, Sulfasalazine, Sulfacetamide) can also cause allergic reactions, ranging from mild to severe rashes through to anaphylaxis (allergic shock). Diagnosis and Treatment -- Skin allergy testing may be useful in some cases of suspected sulfonamide antibiotic allergy, but is not considered useful for assessing adverse reactions to sulfite preservatives. -- The optimal treatment for both Sulfite and Sulfonamide allergies is avoidance of the food or medicines containing these allergens.