Allergies to Drugs

DESCRIPTION
* When the body's immune system reacts adversely to medication, it can exhibit an allergic (rejection) reaction. Any medication can cause an allergic reaction. The reasons are individual, varying from patient to patient. Such reactions may range from mild to severe and life threatening.


SYMPTOMS
* Hives
* Skin rash
* Swelling of lips, gums, and tongue
* Tightness in the throat
* Stridor (wheezing/whistling) sound in the neck
* Shortness of breath
* Wheezing in the chest
* Circulatory collapse (very Low Blood Pressure)
* Late reactions may include fever, joint pain/stiffness, and edema (swelling in the legs and arms).

HOW THE DIAGNOSIS IS MADE
* Often made from a history of taking certain medications that cause symptoms described above
* Laboratory:
* Allergy testing -- skin "prick" allergy testing
* Provocation testing -- direct challenge of the potential allergic agent under controlled conditions
* Bronchoprovocation testing -- an aerosolized solution of the potential allergic medication is given under controlled conditions. Lung function is measured before and after.
* Oral challenge -- medicine is given by mouth in a controlled environment.

TREATMENT
* Rapid desensitization -- the individual is given minute doses of the very medications he is allergic to, followed by gradual increase to full strength over a period of hours. This has been especially effective in treating Penicillin and Insulin allergies.

MISCELLANEOUS
* Cross Reactivity

- If one medication causes an allergic medication, other closely related medications are also likely to cause an allergic reaction. This is especially true with antibiotics. For example, patients who are allergic to the Penicillin family (e.g., Penicillin, Amoxicillin, Dicloxacillin) have up to a 10% chance of reacting to the Cephalosporin family of antibiotics (e.g. Keflex, Ceftin, Cefaclor).