(BMJ)—A 29-yo man w/ URI sx took an OTC flu medication and w/in 30min developed red, itchy skin, w/ a burning sensation in the groin and axillae. One hr later, he felt skin pain and malaise. PMHx unremarkable aside from infantile eczema; no recent travel; 1 instance of unprotected sex w/ female sex worker 1mo earlier. Exam: T 38°C, HR 120, BP 110/56 mm Hg. Skin: confluent erythema, w/ petechiae and edema of lower legs; diffuse adenopathy; no mucosal involvement. Labs: leukocytosis w/ neutrophilic shift, eosinophilia, raised inflammatory markers. What is the dx?
Pityriasis rubra pilaris
Drug hypersensitivity syndrome
Staphylococcal scalded skin syndrome
HIV seroconversion
Toxic epidermal necrolysis
You are correct. The temporal association between taking the flu remedy and the onset of clinical signs, together w/ blood and skin bx results, suggested drug hypersensitivity syndrome. Diagnostic criteria for drug hypersensitivity syndrome include: hospital admission; reaction thought to be drug related; acute rash; T ~38°C; enlarged lymph nodes at 2 sites; at least 1 internal organ affected. This pt improved over 7 days and had a positive intradermal response to phenylephedrine found in the OTC flu remedy.

BMJ 2013;346:f3613