“I started a new tablet, now I’ve got a spreading rash, blisters and my mouth and eyes are raw”

STEVENS-JOHNSON SYNDROME / TOXIC EPIDERMAL NECROLYSIS (SJS/TEN) is a life-threatening severe cutaneous adverse drug reaction: a recent culprit DRUG plus a PAINFUL (not merely itchy) rash with dusky/target macules, BLISTERS and skin detachment (Nikolsky+), and crucially MUCOSAL erosions of ≥2 of mouth/eyes/genitals, with fever and systemic illness (SJS <10% body-surface detachment, SJS/TEN overlap 10–30%, TEN >30% — BAD UK guidelines 2016). The combination of mucosal involvement, skin detachment and a culprit drug is the alarm. Identify the culprit (antiepileptics — lamotrigine/carbamazepine/phenytoin; allopurinol; sulfonamide/other antibiotics; oxicam NSAIDs; nevirapine), typically started days-weeks before, and STOP it immediately (for an antiepileptic the hospital arranges safe seizure cover), documenting a severe drug allergy and reporting on a Yellow Card (MHRA), since re-exposure can be fatal and prompt withdrawal improves outcome. Recognise an EMERGENCY with significant mortality (skin failure causes fluid/electrolyte loss, thermoregulation failure, infection/sepsis, eye/mucosal complications) and arrange IMMEDIATE admission — dermatology with burns/ITU-level supportive care and EARLY ophthalmology, with a sepsis risk assessment (NICE NG253; observations cannot be taken on video) — not community management. Know the differential: erythema multiforme (milder, target lesions, often post-HSV, less mucosal/systemic), staphylococcal scalded skin (mostly young children, no mucosa), and DRESS (rash, fever, eosinophilia, organ involvement). Communicate the urgency clearly but calmly, arrange emergency transfer, and ensure the drug is stopped and documented. The skill is rapid pattern recognition, stopping the drug, and emergency admission — not a community antihistamine.