Sulfa Drug Allergy

A sulfa drug allergy is one of the more common drug allergies. Sulfa drugs are used for bacterial infections, although more recently they've been replaced by antibiotics because resistance to them has emerged among many microorganisms (especially streptococci, meningococci, and shigella), making them less effective.

In general, adverse reactions to drugs are not uncommon, and almost any drug can cause an adverse reaction. Reactions range from irritating or mild side effects such as nausea and vomiting, to allergic reactions, including life-threatening anaphylaxis. Some drug reactions are idiosyncratic (unusual effects of the medication). For example, aspirin can cause nonallergic hives (no antibodies formed), or it may trigger asthma. Only a small proportion of these reactions are allergic in nature.

True drug allergies occur when there is an allergic reaction to a medication. This is caused by hypersensitivity of the immune system, leading to an incorrect response against a substance that is harmless in most people. The body becomes sensitized (the immune system is triggered) by the first exposure to the medication. The second or subsequent exposure causes an immune response, including the production of antibodies and release of histamine.

An examination of the skin and face may show hives, rash, or angioedema (swelling of the lips, face, or tongue). Decreased blood pressure, wheezing, and other signs may indicate an anaphylactic reaction.

Skin testing should confirm a sulfa drug allergy. In addition, such testing should be available in your physician's office without a need for a specialist.

You also want to be aware that sulfa based drugs are not confined to antibiotics. There are certain diabetic drugs, as well as diuretics, saluretics, and natriuretics, which are sulfa based and should be avoid. In addition, you should also avoid the antibiotic Pediazole, which contains sulfisoxazole — an ingredient closely related to sulfamethoxazole.

It's wise not to try to navigate the sulfa drug lanscape on your own. Work closely with your physician to determine if you have a sulfa drug allergy, and develop alternatives for maintaining your good health.