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Case Reports

Abstract

Iododerma is a rare cutaneous hypersensitivity reaction to iodine- or iodide-containing compounds. Patients often present with pustules, nodules, or ulcerative lesions, with variable histopathological findings. We report the case of a 56-year-old male with chronic kidney disease who developed erythematous papulonodular lesions on both upper cheeks shortly after exposure to contrast material and hydralazine injection. His urine iodine level was markedly elevated at 46,576 mg/24 h (reference: 75–851), and C-ANCA was positive at 1:128. The clinical differential diagnoses included Sweet syndrome, granulomatosis with polyangiitis, Demodex infestation, and iododerma. Skin punch biopsy revealed a dermal neutrophilic infiltrate with nodular aggregates of basophilic bodies resembling yeast forms, surrounded by clear vacuolated spaces (“cryptococcus-like” forms). Some of these structures contained neutrophils. No bacteria, fungi, or mycobacteria were detected by Gram, periodic acid–Schiff, GMS, Fite, or acid-fast stains. Mucicarmine and Fontana–Masson stains were negative. MPO highlighted the clusters of cryptococcal-like structures, whereas CD68 and CD163 labeled scattered histiocytes at the periphery of these clusters. Overall, given the patient’s markedly elevated iodine levels, acute iododerma presenting as cryptococcoid neutrophilic dermatitis was favored. The possibility of drug-induced cryptococcoid Sweet syndrome was considered but was not favored. This case highlights the histopathological overlaps between iododerma and cryptococcoid Sweet syndrome and underscores the importance of integrating exposure history, histopathology, and ancillary studies to establish the correct diagnosis.