Perifollicular Inflammation and Fibrosis in Androgenetic Alopecia: Implications for Diagnosis and Treatment - A Comparative Histopathologic and Clinical Study with Normal-Appearing Scalp

PIILIF represents an under‑recognized inflammatory endotype within AGA that may account for treatment resistance in some patients. Early biopsy can confirm the diagnosis, and therapy targeting hormonal and immune pathways may improve outcomes. Routine trichoscopy with a low threshold to biopsy perifollicularly abnormal units showing mild erythema, scale, or hyperpigmented collars can guide care, particularly in treatment resistant or equivocal cases. The broader systemic implications of this inflammatory signature merit further investigation.