Alopecia (Hair Loss)
Hair loss is categorized clinically as either non-scarring (follicles preserved) or scarring (follicular destruction). Accurate classification is key to guiding management.
Primary Classifications
| Condition | Type | Clinical Features |
|---|---|---|
| Alopecia Areata | Non-scarring | Well-demarcated patches; “Exclamation point” hairs. |
| Androgenetic | Non-scarring | Miniaturization; male/female pattern thinning. |
| Telogen Effluvium | Non-scarring | Diffuse shedding after stress/illness/pregnancy. |
| Discoid Lupus | Scarring | Erythema, atrophy, and follicular plugging. |
Diagnostic Pearls
- Pull Test: Gently pulling ~50 hairs; >6 hairs coming out suggests active shedding (common in Telogen Effluvium or Alopecia Areata).
- Scarring vs. Non-Scarring: A clinical sign of scarring is the absence of follicular ostia (the tiny pores where hair exits) on exam. A biopsy is indicated for suspected scarring alopecia to prevent permanent loss.
High-Yield Exam Pearl:
- Alopecia Areata: Frequently associated with other autoimmune diseases, such as **Vitiligo** and **Thyroiditis**.
- Trichotillomania: Characterized by hairs of varying lengths (due to pulling) in an irregular, patchy distribution; biopsy would show normal follicles (no inflammation).