Acquired Localized Hypertrichosis Following Cast Application for Fracture

A 26-year-old female developed localized hypertrichosis, characterized by increased hair growth, on her left forearm following the application of a fiberglass cast for a fracture. This condition, which involved both coarse and fine hair, resolved spontaneously after 5 months. The phenomenon is attributed to cutaneous hyperemia, a transient increase in blood flow and metabolism in the affected area, often seen after chronic irritation or trauma, such as cast application. The case highlights that acquired localized hypertrichosis following cast application is a benign and temporary condition, not requiring further investigation.