A 6-year-old boy has multiple circular, hypopigmented patches on the trunk with slightly scaly margins, not associated with sensory loss or nerve thickening. Examination with Wood's lamp shows dull white fluorescence. The most likely diagnosis is:
- A Pityriasis alba — common childhood hypopigmentation, post-inflammatory, often on face/trunk ✓
- B Indeterminate leprosy — requires biopsy and slit-skin smear
- C Tinea versicolor — Malassezia; shows yellow-green fluorescence on Wood's lamp
- D Vitiligo — complete depigmentation with milk-white fluorescence on Wood's lamp
Correct answer: A. Pityriasis alba — common childhood hypopigmentation, post-inflammatory, often on face/trunk
Explanation
Pityriasis alba is a common, benign hypopigmentation in children, typically on the face and upper trunk, with fine scaling, no sensory deficit, and no nerve thickening. Wood's lamp shows indistinct, dull white enhancement (not the brilliant white of vitiligo). It is often post-inflammatory and associated with atopic tendency. Tinea versicolor shows yellow-green fluorescence. Leprosy patches would have sensory loss and nerve changes. Vitiligo shows brilliant chalk-white fluorescence on Wood's lamp and complete (not partial) depigmentation.
Reference: Ghai Essential Pediatrics, 10th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.