Allergies to drugs

Summary

Features

As a well-accepted medical/scientific iatrogenic problem, allergies to drugs have high human and medical costs. Human costs include discomfort, dysfunction and, sometimes, death. Medical costs concern emergency care to reverse acute hypersensitivity effects, expensive and semi-reliable diagnostic tests and the health risks of re-administration to definitively confirm the drug allergy.

These sensitivities are often termed ‘side-effects’ since they are epiphenomenal to the drug's intended effect. This minimization in the terminology does not reflect the medical reality either in terms of intensity or impact. These adverse reactions to drugs are real, and can be life-threatening. The phrase ‘concurrent effects’ better describes these effects.

Three different types of drug allergies have been detailed (Pichler, 1993): (1) classic drug allergies are immune over-reactions to the medication itself; (2) an immune reaction occurs but is not mediated by other immune substances; (3) an autoimmune reaction can occur when the drug invokes an immune reaction to autologous structures.

The physical sequelae of an allergy to drugs can vary widely. Symptoms may be as benign as simple mild skin rashes, or as threatening as potentially fatal anaphylactic reactions. Anaphylaxis, a constriction of smooth muscles, results in a reddening and swelling of affected areas. If the breathing passages are swollen, suffocation can occur. Death from drug allergies emanates from anaphylactic shock is unabated by medical counter measures.

Particular aspects of antibiotics termed beta-lactams often cause allergic reactions. Allergy to penicillin is quite common, and the most extensively researched of the known drug allergies.