Telogen Effluvium: Is There a Need for a New Classification?

In the letter to the editor, Alfredo Rebora addresses the need for a new classification of telogen effluvium (TE) and clarifies the concept of alopecia areata incognita (AAI). Rebora argues that AAI is not the same as diffuse alopecia areata (AA), as AAI is characterized by diffuse shedding of telogen hairs without clear bald patches, which may overlap with "inflammatory/autoimmune" TE. He also suggests that the autoimmune nature of TE is similar to AA, noting a common history of emotional stress and association with Hashimoto thyroiditis. Rebora acknowledges the difficulty in diagnosing TE due to the time-consuming nature of examining shed hairs under a microscope and suggests the modified wash test (MWT) as a simpler alternative. He emphasizes the need for a more user-friendly classification system for TE, as current classifications are rarely used in practice. Rebora describes a common clinical presentation of TE in women, often associated with Hashimoto thyroiditis, and proposes the possibility of a TE-androgenetic alopecia (TE-AGA) overlap. He concludes by stating the importance of recognizing and naming this distinct clinical entity for proper diagnosis and treatment.