Abnormal Inner Root Sheath of the Hair Follicle in the Loose Anagen Hair Syndrome: An Ultrastructural Study

The study investigated the microscopic changes in hair follicles associated with loose anagen hair syndrome (LAHS) by examining biopsy specimens from 4 patients (3 children and 1 adult) using light and electron microscopy. The findings revealed significant structural abnormalities in the inner root sheath complex of the anagen follicle, including irregular swelling of the keratinized Henle cell layer, irregular keratinization of cuticle cells, and a swollen appearance of Huxley cells. These abnormalities likely disrupted the inner root sheath's supportive and anchoring functions, leading to the loose attachment of the hair shaft characteristic of LAHS. The study was limited by the small number of patients.