Supravenous Repigmentation of Hair Shafts in a Patient with Regrowing Alopecia Totalis: A Case Report and Hypothesis.

Introduction: Alopecia areata (AA) is a type of nonscarring alopecia that has autoimmune etiology, in which the hair follicle, usually an immune-privileged site, becomes the target of attack. Alopecia totalis (AT) is a subset of AA in which patients completely lose hair on the scalp. Initial hair regrowth is often fine and without pigment. We present a case of AT in which pigmented hair grew only overlying superficial veins, a finding which has not been previously reported. Case Presentation: An adult female with brown hair presented with AA that progressed to AT despite the use of triamcinolone ointment and topical 2% tofacitinib ointment. She was treated with nightly augmented betamethasone dipropionate 0.05% ointment under occlusion. Two months later, she noticed diffuse regrowth of thin hair on her scalp, most of which was depigmented. However, linear bands of darkly pigmented hairs were noted overlying superficial scalp veins. Discussion/Conclusion: Loss of pigmentation and subsequent repigmentation of the hair shaft in regrowing AA is not entirely understood. Initial hair regrowth in AA tends to be fine and depigmented, although the hair will usually regain normal texture and color. Pigmentation following a vein suggests that local temperature may play a role, possibly augmented by corticosteroid induced reduced expression of inflammatory cytokines and endothelial release of the vasoconstrictor hormone endothelin, which stimulates melanogenesis.