C. Erosive pustular dermatosis
Examination of the biopsy specimen showed an ulcer with folliculitis and impetiginized neutrophilic crust. A 10-day course of cephalexin led to no change in his scalp eruption, confirming the clinical impression of erosive pustular dermatosis of the scalp (EPDS) in the setting of cetuximab therapy. He started a regimen of clobetasol propionate ointment, 0.05%, twice daily and marked improvement was noted at the 1-month follow-up visit (Figure 2). Given the significant improvement, his topical regimen was changed to tacrolimus ointment, 0.1%, on weekdays and clobetasol ointment on weekends to minimize the risk of skin atrophy. He restarted his oncologic treatment regimen shortly after diagnosis and the scalp eruption remained well controlled, with residual scarring and postinflammatory hyperpigmentation. After 3 months without flares, topical therapies were discontinued.