Alopecia universalis in an HIV-positive patient: possible insight into pathogenesis

Alopecia universalis, a variant of alopecia areata, is a disease of unknown etiology, though evidence for an autoimmune etiology continues to mount. We report an HIV-positive patient with altered T-lymphocyte subsets in whom alopecia universalis developed. A skin biopsy of the patient's scalp demonstrated a classic perifollicular lymphocytic infiltrate, and immunophenotyping of the same specimen revealed that the majority of the cells were CD4+ lymphocytes. During the active loss of hair, the patient's CD4/CD8 ratio was decreased. This ratio normalized during the period of regrowth. Our data suggest that systemic immune dysfunction, as seen in HIV infection, may be more important in mediating alopecia areata than localized immune responses. Given the proposed mechanism of alopecia areata developing in this patient, i.e. influx of CD4+ lymphocytes to the perifollicular regions of skin when the CD4/CD8 ratio is low, it is surprising that alopecia areata is not seen more commonly in patients with HIV infection.