Frontal Fibrosing Alopecia: An Update.

In this review, we discuss recent developments in our understanding of frontal fibrosing alopecia, a disease that has become increasingly common and widespread since its first description in 1994. An inherited predisposition to frontal fibrosing alopecia, previously suspected from the occurrence of familial cases, has been confirmed through genetic studies. Nevertheless, the epidemiology continues to implicate environmental factors in the aetiology. The search has focussed mainly on personal skin care products such as facial moisturisers and UV filters, and there is also some evidence implicating exogenous oestrogens, but confirmation of direct causal links has so far proved elusive. The pathologic mechanisms underlying follicular deletion are being clarified, including the nature of the inflammatory component, the loss of follicular immune privilege in the bulge region and the role of epithelial-mesenchymal transition in the scarring process. Lichen planus pigmentosus, a common accompaniment to frontal fibrosing alopecia in those with darker skin, is probably a feature of the same pathology affecting interfollicular epidermis, rather than a co-morbidity, and may offer new clues to the aetiology. Treatment is still based largely on retrospective case series and variable endpoints. However, methods for assessing frontal fibrosing alopecia and monitoring treatment responses have been strengthened and randomised controlled trials with novel agents (e.g. Janus kinase inhibitors) are in progress. As the main aim of effective treatment is to prevent disease progression, early diagnosis will remain an important target, as will prevention in the longer term.