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Case Reports

Abstract

Necrotizing infundibular crystalline folliculitis (NICF) is a rare and idiopathic inflammatory disorder characterized by the formation of filamentous crystalline deposits of unknown origin. First described in 1999, this disorder is clinically notable for white, hyperkeratotic papules on an erythematous base, though the exact cause of the characteristic crystalline deposits is still controversial. The leading proposed etiologies include physical or chemical trauma, or an infection such as gram-positive bacteria or Malassezia yeasts triggering the production of monosodium urate; the latter theory is supported by the resolution of the eruption following treatment with topical and systemic antimycotic treatment. NICF presents equally in both sexes, often in the 5th decade in the same distribution as classic acne vulgaris. We report a case of a 77-year-old female who presented with a 10-day history of a pruritic umbilical eruption, unresponsive to over-the-counter antifungals. On exam, there were hard white papules on a pink base within the umbilicus. A 5 mm punch biopsy was done, which demonstrated crystalline-appearing material within a crateriform area of epithelial erosion, with flanking spongiosis. A diagnosis of NICF was made given the clinical picture and biopsy findings. While initial treatment with topical clotrimazole was unsuccessful, the patient demonstrated a good response to topical clindamycin gel twice daily with resolution shortly thereafter. We present this case due to its remarkable clinical features and to highlight the management of recalcitrant NICF.