Melasma is classified by Wood's lamp examination into epidermal, dermal, and mixed types. Dermal melasma appears darker on Wood's lamp compared to surrounding skin: True or False? And which type responds BEST to topical treatment?

• A True; dermal type responds best
• B True; mixed type responds best
• C False; mixed type responds best
• D False — dermal melasma does NOT enhance on Wood's lamp; epidermal type responds best to topical therapy ✓

Explanation

Wood's lamp classification of melasma: Epidermal type enhances (darkens) under Wood's lamp because the superficial melanin absorbs UV. Dermal type does NOT enhance — the deep pigment does not interact significantly with 365 nm UV. Mixed type shows partial enhancement. Epidermal melasma responds best to topical depigmenting agents (triple combination: hydroquinone + tretinoin + steroid; or azelaic acid, kojic acid). Dermal and mixed types respond poorly to topical agents and may require chemical peels or laser (Q-switched Nd:YAG) with great caution.

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.