Transient isolated scrotal hair development in infancy.

Isolated scrotal hair development in infancy is a rare disorder that has not been well characterized in the literature. We present a retrospective analysis of 5 male patients referred to the Endocrine Department at the age of 3 to 6 months for the assessment of isolated scrotal hair development. There were no other signs of androgenization and testes were of normal infant size. Three mothers were receiving dydrogesterone during pregnancy and one of them was also receiving desogestrel during breast-feeding. All infants were developing well. In all boys, complete regression of scrotal hair was noted after 4 to 7 months of observation. It seems that the condition is benign and probably occurs in boys with increased response of cells within hair follicles to raised androgen levels during "mini puberty" of early infancy. Nevertheless, all infants with signs of androgenization need urgent full investigation and probably further follow-up until puberty.