NB-UVB Failure — SCE Dermatology MCQ

Correct answer: E — Declare NB-UVB failure and consider systemic therapy — response should be evident by 20-30 treatments

If adequate improvement has not been achieved after 20-30 NB-UVB treatments (a standard course), phototherapy should be considered to have failed. BAD guidelines recommend assessing response at approximately 20 treatments — if the response trajectory is poor, continuing further treatments is unlikely to achieve a satisfactory outcome. This treatment failure then meets one of the eligibility criteria for systemic therapy (conventional systemics first, then biologics if these fail). Extending phototherapy courses beyond 30 treatments increases cumulative UV dose without commensurate benefit and delays access to more effective therapy. The patient should be counselled and transitioned to systemic therapy.

Reference: BAD 2019 Phototherapy; BAD 2020 Biologic