Adverse Events Leading to Discontinuation of Phototherapy: An Observational Study.

The aim of this prospective study in a phototherapy unit was to describe adverse events (AEs) associated with discontinuation of phototherapy in a clinical setting. A total of 872 included patients received 1,256 courses of phototherapy treatment: 76.9% narrow-band UVB (NBUVB); 9.6% systemic psoralen plus UVA (PUVA); 11.4% topical PUVA; and 2.1% UVA. Approximately a fifth of the treatments (n = 240, 19.1%) were associated with AEs, the most frequent of which was erythema (8.8%). Systemic PUVA had the highest rate of AEs (32.5%). Mycosis fungoides was the dermatosis with the highest rate of AE (36.9%). A total of 216 (17.2%) patients stopped treatment: 23.6% because of AEs (4.1% of all treatments). Treatment suspension due to AEs was associated with PUVA, both topical and systemic (p < 0.001), and diagnoses of mycosis fungoides (p <0.001), palmoplantar psoriasis (p = 0.002), hand eczema (p = 0.002) and pityriasis lichenoides (p = 0.01). In conclusion, one in every 5 patients receiving phototherapy had an AE, but few stopped treatment for this reason.