Severe reaction to sulfa drug, itchy rash, made man’s life miserable

I am a 78-yearold male in fairly good health. I recently was prescribed Bactrim (a sulfa drug) for an ear infection but didn’t know I am allergic to sulfa. I had a severe reaction to the drug: a raging, very itchy rash on most of my body. It made my life miserable. I was given prednisone, which did not help a great deal. I was also given hydroxyzine and triamcinolone ointment, which helped somewhat. I had this condition for three months before the rash and itch subsided. Since this episode I have talked to many people who have either had a reaction to sulfa or know someone who has.

Why do doctors continue to prescribe sulfa drugs when there seems to be such a high probability of a reaction? Why hasn’t a test been developed to determine if a person has this allergy before prescribing it?

— A.R. DEAR READER » All antibiotics share the risk of allergic reactions; some more than others.

About 8% of people are allergic to sulfa drugs, with women being twice as likely. In most cases, the reaction is a rash that begins after three days or so on the antibiotic, and goes away promptly when the drug is discontinued. However, there is another notable reaction that usually begins a week or two after starting the medicine, and lasts for weeks. This type of reaction can be very serious, with some people developing multiple organ involvement. There are still other types of allergic reactions to sulfa drugs, which can also be serious — even fatal. Fortunately, most of the 8% of people will have the least dangerous form of allergy.

Attempts to create a test to predict (or even confirm) a sulfa allergy have not been successful, and none is available.

Doctors need to have a healthy respect for sulfa allergies, and prescribe these medicines only when the benefit would outweigh the risk.