Folliculocentric Herpes: A Clinicopathological Study of 28 Patients.

BACKGROUND: The cutaneous manifestations of herpes infection are primarily in the context of active infection and of the post-herpetic zosteriform eruption. The former manifests cytopathic alterations diagnostic of herpes. The latter includes lichen planus-like and granuloma annulare-like eruptions and lymphocytoma cutis.

METHODS: We encountered skin biopsies from 28 patients whose acute or chronic herpetic or post-herpetic zosteriform lesions manifested folliculocentricity. The clinical appearance of the lesions was correlated with the histopathologic and immunohistochemical features of paraffin-embedded skin biopsies to determine the specific viral etiology. A history of underlying medical disease was noted if present.

RESULTS: There were 16 men and 12 women with a folliculocentric eruption occurring after a known herpetic eruption or manifesting cytopathic changes and/or immunohistochemical findings compatible with herpes virus in lesional skin biopsies. Underlying immune dysregulatory states were present in most cases, namely, malignancy, anticonvulsant or antidepressant therapy, diabetes mellitus, psoriasis, Crohn disease, and other conditions. All biopsies demonstrated dense lymphohistiocytic infiltrates in or around hair follicles with variable necrosis, while active infections also showed cytopathic and/or immunohistochemical evidence of herpetic alterations, most commonly varicella zoster. Other features included interfollicular interface dermatitis, lymphocytic eccrine hidradenitis, neuritis, and folliculocentric vasculitis.

CONCLUSIONS: Cutaneous herpetic eruptions can evoke a predominantly folliculocentric mononuclear cell reaction and vasculitis; there is an association with underlying endogenous and/or iatrogenic immune dysregulation. Most cases are secondary to reactivation of varicella zoster. The histomorphology suggests a role for cell-mediated immunity. Antigenic homology of an endogenous 72-kd heat shock protein in follicles with that of a herpetic heat shock protein, in concert with an intrafollicular proliferative response of γ-δ T lymphocytes, may explain the follicular localization and composition of the infiltrate.