Severe cutaneous adverse reactions to medications (SCARs) include drug reaction with eosinophilia and systemic symptoms, Stevens-Johnson syndrome, toxic epidermal necrolysis, and acute generalized exanthematous pustulosis. They are all non-immunoglobulin E mediated hypersensitivity reaction patterns, distinguished from simple cutaneous drug eruptions by immunologic pathogenesis and internal organ involvement. Herein the clinical features, diagnostic workup, and management considerations are presented for each of these major SCARs.