Non‐invasive method distinguishes chronic telogen effluvium from mild female pattern hair loss: clinicopathological correlation

Abstract Background The distinction between chronic telogen effluvium ( CTE ) and female pattern hair loss ( FPHL ) is important because of their different prognosis and treatment. Non‐invasive methods have been described to be useful in differentiating FPHL from CTE . This prospective study investigated the use of the washing method to differentiate CTE from mild FPHL . Methods Twenty patients with CTE and 17 with FPHL were recruited and followed for 18 months. The diagnosis was established through clinical, laboratory, and histological studies. The patients were asked to abstain from washing their hair for 5 days and then shampoo and collect all hair shed in the process. Hair shafts were then counted and divided into two groups: up to 3 cm in length or longer. Results In the CTE group, the mean hair count was high (438), and in all cases, <10% were short. In patients with FPHL , the mean count was not as high (215) and in only one patient, short hairs comprised <10% of the total. The greater the number of long hairs, the higher was the density of terminal follicles seen histologically. The CTE group presented a greater number of patients with serum iron values <70 μg/dl. Ferritin levels ranged from 6.98 to 128.33, average of 66.65 ( CTE ), and 16.5–304.8, average of 114.97 ng/ml ( FPHL ), but no significant differences were found. Conclusion The washing test can be useful to avoid biopsy procedures. Iron serum levels are possibly an additional parameter that may improve CTE diagnosis if combined with an earlier test.