Von Frey hair

A von Frey hair is a type of aesthesiometer designed in 1896 by Maximilian von Frey. It is used in Nociception assay

These hairs are made from nylon filaments of varying diameter. The hairs are to be pressed against the skin with enough force so that the hair buckles and forms a U-shape. Given that the force required for this is assumed to be constant, these hairs can be used to apply a very accurate force on specific areas of the skin, thus making von Frey hairs a possible diagnostic, research, and screening tool.

von Frey hairs are readily used to study skin areas with normal responsiveness, as well as hyper- or hyposensitive areas.