A 10-year-old boy presents with hypopigmented, slightly scaly patches on the face and upper arms that do not tan. Wood's lamp examination shows dull, poorly demarcated hypopigmentation. There is no complete depigmentation. KOH scraping is negative. The child is otherwise well and in school. Which diagnosis is MOST likely?

• A Pityriasis versicolor (Tinea versicolor)
• B Vitiligo
• C Nevus depigmentosus
• D Pityriasis alba ✓

Explanation

Pityriasis alba is a common, benign form of mild eczema seen in children aged 3–16 years, characterized by hypopigmented (not fully depigmented), slightly scaly, ill-defined patches on the face (especially cheeks) and upper extremities that become more apparent in summer due to contrast with tanned surrounding skin. Wood's lamp shows dull hypopigmentation (not the chalk-white of vitiligo). KOH is negative (unlike pityriasis versicolor). Vitiligo shows complete depigmentation with chalk-white fluorescence on Wood's lamp. Nevus depigmentosus is a stable birthmark present from infancy.

Reference: Ghai Essential Pediatrics, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.