Drug Reactions, NEET PG & INI-CET Dermatology MCQs

Explanation

Stevens-Johnson syndrome is a severe drug reaction with mucosal erosions and epidermal detachment of under 10% of body surface area; 10 to 30% is overlap and over 30% is toxic epidermal necrolysis. Common triggers include anticonvulsants, sulphonamides, and allopurinol; stop the drug and give supportive care.

Explanation

Toxic epidermal necrolysis involves epidermal detachment of over 30% of body surface area, the most severe end of the SJS/TEN spectrum, with high mortality. It requires urgent withdrawal of the causative drug and intensive supportive care, often in a burns unit.

Explanation

A fixed drug eruption recurs at the same site each time the offending drug — commonly sulphonamides, NSAIDs, or tetracyclines — is taken, as a well-defined dusky or violaceous patch that may leave hyperpigmentation. Identifying and avoiding the drug is the treatment.

Explanation

Erythema nodosum is a panniculitis presenting as tender red nodules, typically on the shins, and is a reactive process associated with streptococcal infection, sarcoidosis, tuberculosis, inflammatory bowel disease, and some drugs. It usually resolves with treatment of the underlying cause.