A 5-year-old child develops sharply defined areas of hair loss on the scalp with broken hairs at the margin ('exclamation mark hairs'). The scalp skin appears normal. No scaling or erythema. The diagnosis is:
- A Tinea capitis
- B Trichotillomania
- C Alopecia areata ✓
- D Traction alopecia
Explanation
Alopecia areata is an autoimmune T-cell mediated condition causing sharply defined patches of non-scarring hair loss. Exclamation mark hairs (tapered, easily extracted hairs narrowed at the scalp end) at the periphery of active patches are pathognomonic. The scalp skin appears normal without scaling or erythema. Tinea capitis causes scaling, erythema and frequently inflamed boggy masses (kerion). Trichotillomania shows irregular, bizarre-shaped patches with broken hairs of varying lengths; hairs are pulled not fallen. Traction alopecia occurs at hairline with clearly defined distribution related to styling.
Reference: Ghai Essential Pediatrics, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.