Human scalp skin and hair follicles express neurotophin-3 and its high- affinity receptor tyrosine kinase C, and show hair cycle-dependent alterations in expression.

Background  Neurotrophin (NT)‐3 and its high‐affinity receptor tyrosine kinase C (Trk C) are essential for nervous system development. These members of the NT family are also involved in murine hair morphogenesis and cycling. However, their role in human hair follicle (HF) biology remains to be elucidated.

Objectives  To explore the role of NTs in human skin and HF biology.

Methods  The immunoreactivity (IR) of NT‐3 and Trk C was studied in human scalp skin and HFs by immunofluorescent and light microscopic immunohistology. Skin biopsies were obtained from normal human scalp containing mainly anagen VI HFs from women (age 53–57 years) undergoing elective plastic surgery.

Results  Both NT‐3 and Trk C showed prominent, yet distinct, IR patterns in human scalp anagen HFs (anagen VI), whereas they were weakly expressed in catagen and increased again in telogen HFs. Within HF .