Cryptococcoid iododerma mimicking neutrophilic dermatosis

Summary: A 40-year-old female with renal failure on hemodialysis, heart failure, coronary artery disease, and hypertension presented for emergency care with new-onset skin lesions after receiving multiple CT imaging studies with contrast over a 2-week period. Medications included hydralazine, levothyroxine, warfarin, venlafaxine, and quetiapine. Exam revealed umbilicated papules and pustules in a facial sebaceous distribution, yellow papules on the eyelid margins, and dusky bullae on the forearms. Biopsy showed diffuse sheets of neutrophils with karyorrhectic debris with a cryptococcoid appearance. Infectious stains (Fite, GMS, Steiner) were negative. Serum iodine levels were markedly elevated at 5,450 mcg/L (normal 52-109). A diagnosis of cryptococcoid iododerma was made. Her skin lesions improved on a high dose prednisone taper. Iododerma most commonly occurs secondary to iodinated contrast, and risk factors include both hydralazine use and end-stage renal disease. Lesions tend to affect the central face due to sebaceous predilection. Clinically, it may mimic neutrophilic dermatoses and infections. In the acute phase, histologically it may mimic cryptococcoid Sweet syndrome, as it did in this case. This case illustrates the importance of considering iododerma in the differential of neutrophilic dermatosis with a cryptococcoid appearance histologically.