1. Loss of Hair Follicle Immune Privilege
Alopecia Areata (AA) is an autoimmune condition targeting anagen-phase hair follicles. The physiological "immune privilege" of the bulb collapses, allowing CD8+NKG2D+ T lymphocytes to infiltrate and halt hair growth without destroying the stem cell compartment, allowing potential regrowth.
2. Diagnostics & Dermoscopy
Trichoscopy demonstrates smooth, round depilated patches with pathognomonic "exclamation-point hairs", yellow dots, and black dots indicating active disease expansion.
3. Modern Therapeutic Escalation
Intralesional triamcinolone acetonide injections (5–10mg/mL) for localized disease; newly approved oral JAK inhibitors (Baricitinib, Ritlecitinib) for severe alopecia totalis or universalis.