Hamilton–Norwood scale

The Hamilton–Norwood scale is used to classify the stages of male pattern baldness. It is a widely accepted and reproducible classification system for male pattern hair loss (androgenetic alopecia). The stages are described with a number from 1 to 7 with a type A variant for the cases with anterior involvement.^[1]

Hamilton–Norwood scale
Part of the Hamilton-Norwood classification system
Synonyms	Norwood scale
Purpose	Used to classify stages of baldness

Overview

Androgenetic alopecia follows a defined pattern of hair loss, beginning with bitemporal recession of the frontal hairline. Eventually, diffuse thinning over the vertex (top) of the scalp occurs. With progression, complete hair loss in this region is common. The bald patch progressively enlarges and eventually joins the receding frontal hairline.

This measurement scale was first introduced by James Hamilton in the 1950s and later revised and updated by O'Tar Norwood in the 1970s.^[2] It is sometimes referred to as the Norwood–Hamilton scale or simply the Norwood scale.

The scale is regularly used by doctors to assess the severity of baldness, but it is not considered very reliable since examiners' conclusions can vary.^[1]

Diagnostic

Dermatologists might use the Norwood Scale on patients to assess male pattern baldness. It is especially used to check if hair loss treatments are helping patients regaining hair.^[1]

See also

• Ludwig scale for female pattern baldness