Stevens-Johnson Syndrome — MFDS Part 1 MCQ

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ModerateOral PathologyStevens-Johnson SyndromeMFDS Part 1

Shortly after starting a new medication, a patient develops fever followed by a painful, widespread dusky targetoid rash involving the palms and trunk. Examination shows extensive oral erosions, haemorrhagic crusting of the lips and conjunctival soreness. What is the most likely diagnosis?

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Correct answer: B — Stevens-Johnson syndrome

The diagnosis is Stevens-Johnson syndrome, an acute and potentially life-threatening mucocutaneous reaction commonly triggered by medication. The discriminating features are the temporal relationship to a new medicine, systemic prodrome, painful targetoid eruption and severe involvement of more than one mucosal site, including oral erosions, haemorrhagic lip crusting and ocular symptoms. Pemphigus vulgaris may cause persistent oral erosions but does not usually produce an acute febrile targetoid drug eruption. Behçet disease causes recurrent oral ulcers, usually with genital ulceration, ocular inflammation or other recurrent systemic manifestations. Simple aphthous ulceration is confined to discrete oral ulcers, while candidiasis typically presents with removable white plaques or erythematous mucosa rather than targetoid skin lesions.

Reference: NHS, Stevens-Johnson syndrome, symptoms and causes, reviewed 4 March 2026. https://www.nhs.uk/conditions/stevens-johnson-syndrome/