Trichorrhexis Nodosa: Clinical and Investigative Studies

In a study of 49 patients with trichorrhexis nodosa (TN), 26 had scalp hair involvement, with 20 of these cases linked to excessive hair trauma. Additionally, 23 patients experienced TN in genito-inguinocrural or multiple sites, all reporting pruritus. The condition often improved with reduced hair trauma or pruritus management. Investigations, including urine chromatography and hair amino acid analysis, did not support a metabolic defect as the cause. The study highlighted trauma as a significant factor, demonstrated by in vitro reproduction of TN through mechanical stress, identifying TN as a common cause of unexplained hair loss.