A 35-year-old woman presents with symmetrical hyperpigmentation of the cheeks, upper lip, and forehead. Wood's lamp examination shows marked enhancement of pigmentation. This indicates that the melanin is predominantly located in the:
- A Dermis (dermal type)
- B Both epidermis and dermis (mixed type)
- C Epidermis (epidermal type) ✓
- D Adnexal structures only
Correct answer: C. Epidermis (epidermal type)
Explanation
Wood's lamp (365 nm UV) enhances the contrast of epidermal melanin (which absorbs UV light) but does not enhance dermal melanin because the dermis scatters UV light rather than absorbing it. Marked enhancement under Wood's lamp indicates predominantly epidermal melasma, which responds better to topical depigmenting agents (hydroquinone, triple combination). Dermal and mixed types show little or no enhancement and have poorer treatment response.
Reference: Neena Khanna Illustrated Synopsis of Dermatology & STD, 6th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.