dermatologic disorders
Drug Eruptions and Reactions
Diagnosis of Drug Eruptions and Reactions
Clinical evaluation and drug exposure history Sometimes skin biopsy A detailed history is often required for diagnosis, including recent use of over-the-counter drugs. Because the reaction may not occur until several days or even weeks after first exposure to the drug, it is important to consider all new drugs and not only the one that has been most recently started. No laboratory tests reliably aid diagnosis, although Skin Biopsy is often suggestive. Sensitivity can be definitively established only by rechallenge with the drug, which may be hazardous and unethical in patients who have had severe reactions. Occasionally, patch testing can be helpful in patients with fixed drug eruptions. 