Prophylactic phototherapy (photohardening) is recommended for severe recurrent polymorphic light eruption before the spring season. The preferred regimen uses:

• A Broadband UVA with oral psoralen (PUVA)
• B Broadband UVB only
• C Narrowband UVB (311 nm) ✓
• D Visible light phototherapy at 420 nm

Explanation

Narrowband UVB (311 nm) is the preferred prophylactic phototherapy for PMLE as it induces hardening with a better safety profile than PUVA. It causes epidermal thickening, melanization, and immunomodulation. PUVA is more effective but carries greater long-term carcinogenic risk and is reserved for refractory cases. Broadband UVB is less effective. Visible light does not induce photohardening for PMLE.

Reference: Rook's Textbook of Dermatology, 9th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.