292 Topical gabapentin for the treatment of symptomatic scalp in cicatricial alopecias

Abstract

Cicatricial alopecias are commonly associated with neuropathic scalp symptoms which can be debilitating and difficult to manage. Recently, topical formulations of gabapentin have shown efficacy in treating neuropathic conditions such as vulvodynia and post-herpetic neuralgia. In this pilot study, we evaluated the safety and efficacy of topical gabapentin for the treatment of neuropathic scalp symptoms in a patient with lymphocytic cicatricial alopecia and scalp pruritus. Topical 6% gabapentin solution was applied to the scalp twice daily for 12 weeks. Study visits every 4 weeks included surveys to evaluate symptoms, clinical examinations, photography, Lichen Planopilaris Activity Index (LPPAI) scoring, and serum gabapentin levels. 4-mm punch biopsies were obtained both pre- (week 0) and post-treatment (week 12) from clinically affected and unaffected scalp. Biopsies were immunostained with antibodies to PGP 9.5 (pan-neuronal marker), type IV collagen, vasoactive intestinal peptide (VIP), calcitonin gene-related peptide (CGRP) and substance P (SP). Neurolucida software was used to analyze confocal images for epidermal nerve fiber (ENF) density according to previously validated techniques. CGRP, SP and VIP density was studied using epifluorescent microscopy. The patient experienced reduction in both disease activity (LPPAI 0.33 versus 1.42) and scalp pruritus (visual analog score 1/10 versus 6/10) compared to pre-treatment values. Incidentally, substantial hair regrowth was noted on affected scalp. Biopsies revealed sparse scalp innervation, consistent with a small fiber neuropathy. Post-treatment biopsies had increased ENF density and VIP expression compared to baseline in both affected and unaffected scalp. Serum gabapentin level remained undetectable, and no adverse effects were reported. These findings suggest that topical gabapentin is safe for the management of symptomatic scalp in cicatricial alopecias. Further studies are needed to determine if epidermal reinnervation and hair regrowth can be replicated.