Acute generalized exanthematous pustulosis induced by ceftriaxone with positive patch testing.

Acute generalized exanthematous pustulosis (AGEP) is a rare severe cutaneous reaction. In over 90% of patients it is an adverse reaction to drugs. Delayed-type (type IV) hypersensitivity seems to play an important role in its pathophysiology. Positive patch tests have ranged from 18% to 75%, with 93 culprit drugs identified. Our case involves an 87-year-old female patient, treated for a periprosthetic joint infection with ceftriaxone and daptomycin, who developed acute generalized exanthematous pustulosis. Clinical diagnosis was confirmed by skin biopsy. Patch testing performed 5 months later confirmed sensitization to ceftriaxone. Patch testing is useful to identify the cause of AGEP when the responsible drug is unclear. [ABSTRACT FROM AUTHOR]