Short Anagen Syndrome

Short anagen syndrome (SAS) was a rarely reported condition characterized by an idiopathic short anagen phase, resulting in the inability to grow long hair. Patients typically had abnormally short scalp hair and reported never having had a haircut. The condition was benign, with no associated systemic diseases or skin disorders, and hair length often improved spontaneously after puberty. The main differential diagnosis was loose anagen hair syndrome (LAS).