Characteristics of the Structural Components of Pilosebaceous Follicles in the Differential Diagnosis of Non-Cicatricial Alopecia
December 2025
in “
Russian Journal of Skin and Venereal Diseases
”
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Studysummary This study found that in patients with non-cicatricial alopecia, hair follicles and their sheaths were thinner compared to controls, especially in cases of alopecia areata and telogen effluvium, with notable thinning beginning in the subcutaneous fat tissue.
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The study investigated the structural components of pilosebaceous follicles in 191 patients with non-cicatricial alopecia compared to 20 control patients. It found that hair follicles in alopecia patients were thinner, particularly in cases of alopecia areata. The external root sheath was consistently thinner across all hair loss groups, with the most significant thinning in alopecia areata and telogen effluvium. The internal root sheath was notably thinner in diffuse telogen effluvium and alopecia areata but not in androgenetic alopecia. In non-alopecia patients, significant changes in follicle thickness occurred at the transition from the reticular dermis to the sebaceous gland, whereas in alopecia patients, thinning began in the subcutaneous fat tissue.
