The Modified Hair Wash Test (MHWT)

A closer look at the MHWT for Differentiating CTE and AGA

The modified hair wash test (MHWT) is an extremely helpful non-invasive test. It is underutilized by dermatologist mainly because of lack of familiarity and exposure. It is an extremely powerful technique to differentiate challenging cases of CTE from AGA. The patient may perform this test at home. 

Performing the MHWT

To perform the MHWT, a patient is instructed to avoid shampooing the hair for 5 days before the date of set test date. On the day of the test, the sink is covered with a gauze. The hair is then shampooed thoroughly and rinsed. The hairs trapped in the gauze are collected counted and divided into hairs less than 3 cm and more than 5 cm.

Interpreting the MHWT

Patients with 10% or more of hairs 3 cm or shorter and who shed fewer than 100 hairs are diagnosed as having AGA; Patients with fewer than 10% of hairs that were 3 cm or shorter and who shed at least 100 hairs were diagnosed as having CTE; Patients with 10% or more of hairs that were 3 cm or shorter and who shed at least 100 hairs were diagnosed as having AGA + CTE; Finally patients with fewer than 10% of hairs that were 3 cm or shorter and who shed fewer than 100 hairs were diagnosed as having CTE in remission.