Erythema Multiforme, SJS & TEN

Key points

• Erythema multiforme: target lesions starting on hands/feet, spreading to torso; most common cause HSV; drugs include penicillins, sulphonamides, carbamazepine, allopurinol, NSAIDs.
• Stevens-Johnson syndrome: severe EM with blistering and mucosal involvement.
• Toxic epidermal necrolysis: life-threatening; scalded appearance, positive Nikolsky's sign; same drug triggers (penicillins, sulphonamides, phenytoin, allopurinol, carbamazepine, NSAIDs).
• TEN management: stop precipitant · supportive care (often ICU) · IVIG now commonly first-line · other options ciclosporin/cyclophosphamide, plasmapheresis.

Decision points in this pathway

• Mucosal involvement + blistering?
• Scalded skin + Nikolsky's sign + systemically unwell?

The full step-by-step algorithm, including what to do at each branch, opens in the app for approved members.