We present a 69-year-old man with type 2 diabetes mellitus and a five-year history of an eruption of follicular pustules, papules, and nodules, which was identified histopathologically as folliculocentric granuloma annulare (GA). Folliculocentric generalized GA is a rarely reported variant of GA, in which the the palisading histiocytes form focal granulomas in a follicular pattern. In this case, the GA may represent an isotopic phenomenon, with lesions developing in hair follicles that were previously affected by a suppurative folliculitis.
Case synopsisHistory: A 69-year-old man presented to the Skin and Cancer Unit for evaluation of a generalized eruption of red-to-purple, mildly pruritic, non-tender papules and nodules, which spared his face, palms, and soles. The eruption had been ongoing for five years at the time of his presentation. The lesions were sometimes vesicular or pustular, and exuded a yellow discharge. He denied any systemic symptoms. Other medical problems include asbestosis (without mesothelioma), type II diabetes mellitus, and hypertension. No medications were started or changed before the eruption developed.Prior to his presentation at the Skin and Cancer Unit, a dermatologist treated the condition with doxycycline, which was used at the onset of the eruption and which helped modestly. He was later treated by other dermatologists with valacyclovir, topical glucocorticoids, and ketoconazole, none of which helped.
Physical examination:In a widespread distribution on the trunk and extremities with sparing of the head, neck, palms, soles, and genitals, crops of erythematous-to-violaceous papules, pustules, and nodules were present. Scattered excoriations were noted. A few crusted lesions were present on the trunk, with occasional vesicles on erythematous bases.
Laboratory data:A complete blood count and comprehensive metabolic panel were normal. Hepatitis B virus surface antigen, surface antibody, and core antibody; hepatitis C virus antibody; human immunodeficiency virus; and QuantiFERON-TB Gold were negative.Histopathology: There is a perifollicular, nodular and interstitial, mixed-cell infiltrate of histiocytes with scattered eosinophils and neutrophils. There are foci of histiocytic aggregates surrounding areas of mucin.