Studies of poliosis — the regrowth of white hairs at the site of previous patches of AA — in patients with alopecia areata (AA) have been limited mostly to case reports of total or partial whitening with pigmented hair loss. In a retrospective analysis published in the Journal of the American Academy of Dermatology, investigators sought to characterize patients who had AA by comparing those with and without poliosis.1
The medical records of 258 patients with AA who had visited Wonju Severance Christian Hospital, in Wonju, Korea, between March 2012 and June 2017 were examined retrospectively. All patients were divided into two subgroups: those with and those without poliosis. The demographic variables (age, gender, body mass index, smoking status, and alcohol use), comorbidities (diabetes mellitus, hypertension, and dyslipidemia), and disease-specific variables (age at onset of AA; extent, duration, recurrence, family history, and history of treatment of AA) of the two subgroups were then compared.
Overall, 13 of the 258 patients (5.04%) had poliosis. The average age of those in the poliosis subgroup was higher than the average age of those in the nonpoliosis subgroup. In addition, both the proportion of patients treated with diphenylcyclopropenone and the proportion of patients with less extensive lesions were higher in the poliosis group than in the nonpoliosis group. With respect to comorbidities, according to multivariate logistic regression analysis, only hypertension was significantly associated with poliosis (P =.032; adjusted P =.038).
In patients with AA, melanocyte-associated T-cell epitopes have been shown to behave like autoantigens. It is believed that hair whitening is caused by an interaction among various mechanisms, such as the dysregulation of signaling pathways and transcription factors in the microenvironment surrounding the hair follicle, including melanocyte stem cells, or by an imbalance in the management of oxidative stress.2 Therefore, poliosis may be induced among elderly persons with AA who have a poor melanocyte reservoir status.
The investigators concluded that because the current analysis was conducted in a specific population of patients, future studies should consider genetic differences in the prevalence of AA and comorbidities according to ethnicity. Moreover, larger sample sizes need to be evaluated, given that the current study included only a small number of participants at a single institution.
1. Lee YB, Jun M, Lee W-S. Alopecia areata and poliosis: a retrospective analysis of 258 cases [published online November 28, 2018]. J Am Acad Dermatol. doi: 10.1016/j.jaad.2018.11.033
2. Harris ML, Fufa TD, Palmer JW, et al; NISC Comparative Sequencing Program. A direct link between MITF, innate immunity, and hair graying. PLoS Biol. 2018;16(5):e2003648.