A method of counting hairs shed during washing to help evaluate excessive shedding.
A wash test is a structured way of estimating how many hairs are lost during washing. The patient may be asked to avoid washing for a defined period, then collect and count shed hairs during a wash. Modified versions may also separate shorter miniaturised hairs from longer terminal hairs. The test is not needed for every patient, but it can help when the main complaint is shedding and the clinician needs to distinguish telogen effluvium from pattern hair loss or mixed presentations.
Starace et al., Female Androgenetic Alopecia, Am J Clin Dermatol 2020: https://doi.org/10.1007/s40257-019-00479-x ; DermNet diffuse alopecia: https://dermnetnz.org/topics/diffuse-alopecia
