Optimal microneedle length for hair regrowth in hair cycle arrest (alopecia X) in six dogs.

Abstract

Hair cycle arrest (HCA) is a chronic alopecic disorder in dogs. Clinical responses vary and are often insufficient. Microneedling (MN) has been used as a successful treatment for HCA in dogs; ideal protocols have not yet been established. The objective of the study was to compare the efficacy and safety of three needle lengths for MN in dogs with HCA. Six unrelated client-owned dogs, including five Pomeranians and one mixed-breed dog, diagnosed with HCA. Individual alopecic sites were divided into three sections. For each section, different lengths of needles (1, 2 and 3 mm) were used. Efficacy and safety were evaluated at 1, 3 and 6 months. Treated sections were monitored for 20 months. Three months after treatment with 3 mm needles, all sections showed hair regrowth. There was no hair regrowth in two of six sections treated with 2 mm needles, and four of six sections did not show a response to treatment with 1 mm needles. Two dogs developed transient pruritus. Five of six dogs had recurrent hair loss between 5 and 16 months of follow-up. Microneedling using longer needles stimulated better hair regrowth in dogs with HCA. Alopecia relapsed in most dogs and minor pruritus occurred in some dogs.