A female pattern hair loss pattern with widening over the central frontal scalp.
The Olsen Christmas tree pattern describes widening of the central parting that is most prominent toward the frontal scalp, creating a triangular or Christmas tree-like shape. It is often used when assessing female pattern hair loss. The frontal hairline may be relatively preserved, while density decreases behind it. This pattern helps distinguish female pattern hair loss from diffuse shedding, although both can coexist. Clinical examination and trichoscopy are usually used together.
Starace et al., Female Androgenetic Alopecia, Am J Clin Dermatol 2020: https://doi.org/10.1007/s40257-019-00479-x ; DermNet female pattern hair loss: https://dermnetnz.org/topics/female-pattern-hair-loss
