While scalp alopecia represents a distinctive feature of chronic graft-versus-host disease (cGVHD), little is known about the clinical and histologic presentation of hair loss.

We sought to classify the clinical presentations and histologic findings of chronic hair loss in patients with cutaneous cGVHD.

A prospective cohort of 17 adult hematopoietic cell transplantation (HCT) recipients with cutaneous cGVHD was enrolled. Dermatologic examinations were performed, and punch biopsy specimens of the scalp were obtained. Biopsy specimens were analyzed with hematoxylin–eosin and immunohistochemical stains in all cases and fluorescence in situ hybridization analyses in specific cases.

Clinically, 4 patterns of hair loss were described—patchy nonscarring (41.2%), diffuse nonscarring (11.8%), diffuse sclerotic (11.8%), and patchy sclerotic (5.9%). The location of the inflammatory infiltrate on hematoxylin–eosin-stained specimens correlated with the hair loss pattern patients had clinically, with cell populations around the bulb and bulge in nonscarring and sclerotic cases, respectively. Fluorescence in situ hybridization studies in female cGVHD patients with male donors demonstrated green Y chromosomes limited to the area of the hair follicle affected by inflammatory cells.

This study describes the various clinical and histologic subtypes of long-standing alopecia in adult cGVHD patients and suggests that this alopecia may be a direct manifestation of cGVHD of the hair follicle.