[Acquired alopecia in childhood].

Hair loss and alopecia occur frequently in children. The prevalence of the underlying causes and conditions, treatment options and prognosis differ in part significantly from adulthood. This article focuses on frequent forms of acquired alopecia which are not associated with inflammation or scarring of the scalp. Special attention is given to alopecia areata as the most important entity and to trichotillomania as its most difficult differential diagnosis. Significant forms of diffuse hair loss include anagen-dystrophic and telogen effluvium, androgenetic alopecia and loose anagen hair.