Chapter 20. Pathogenesis and Treatment of Alopecias

Abstract

Publisher Summary This chapter discusses the pathogenesis and treatment of alopecia areata and androgenetic alopecia; that are two common nonscarring alopecias because of fundamental changes in the functioning of the hair follicles. Both alopecia areata and androgenetic alopecia involve perturbation of the normal hair growth cycle. Alopecia areata and androgenetic alopecia are characterized by a higher percentage of telogen hair follicles and loss of hair from those follicles. Corticosteroids have frequently been used for the treatment of alopecia areata. Topical application and intralesional injection appear to be the safest and most efficacious routes of administration. Alopecia areata has also been treated with PUVA therapy that combines administration of topical or oral psoralens with UVA irradiation. Inosiplex and thymopentin are immunostimulants that have been used to treat alopecia areata. Androgenetic alopecia apparently involves undefined genetic factors that have been variously hypothesized to be levated androgen metabolism, decreased levels of sex hormone binding globulins, or increased androgen binding in target tissues. In females, oral spironolactone, cyproterone acetate, and cimetidine have been reported to result in some hair regrowth, presumably because of the antiandrogenic properties of these compounds. Other agents that are not involved with androgenic pathways have shown hair growth stimulating properties in androgenetic alopecia. Topical minoxidil has received by far the greatest amount of study for the treatment of androgenetic alopecia, and several recent reviews have appeared that summarize the results. Minoxidil has shown hair growth stimulating activity in both alopecia areata and androgenetic alopecia. Further development of hair growth promoters is critically dependent on the discovery of a rapid and accurate assay system that has some known relationship to alopecia in humans. Future areas of research should focus on the development of agents with greater efficacy and safety.