Phototherapy for atopic dermatitis: Is the light still shining?

The medical management of atopic dermatitis (AD) has dramatically changed within the last few years due to the availability of an increasing number of biologics and Janus kinase inhibitors that have gained approval for use in patients with moderate to severe AD. In parallel, conventional immunosuppressants such as ciclosporin, azathioprine, methotrexate and mycophenolate mofetil are slowly losing in importance, the more so as, with the exception of ciclosporin, all of these drugs are not licensed for AD and thus used off-label.1 For patients with more extensive disease that cannot be adequately controlled with topical measures phototherapies represent a valuable and probably underused alternative to systemic medications.2 Narrowband-UVB (NB UVB) due to its good efficacy, ease of use and favourable long-term safety has over the last decades evolved as the most widely used type of phototherapy. Photochemotherapy (PUVA), on the contrary, is more difficult to perform and associated with a higher risk of short- and long-term hazards and has therefore been largely replaced by NB UVB. Finally, UVA1 phototherapy devices are expensive and bulky and their availability is mostly restricted to centres that are specialized in phototherapies. Numerous studies in the past have shown that phototherapies are effective in treating AD. Unfortunately, the overall level of evidence for these trials is low because of small numbers of included patients and a great heterogeneity in trial design.3 To improve routine use and provide information for future research objectives Steyn et al. in this issue of the JEADV report on the results of an electronic survey of how phototherapy was prescribed and conducted in 27 European countries until July 2021.4 Not surprisingly, the authors found that NB UVB was the most widely employed phototherapeutic modality for adult and paediatric patients and that PUVA and UVA1 were used to a much lesser extent. The study also revealed great differences across European phototherapy centres in performing phototherapy and assessment of the therapeutic outcome. With regard to varying practices, however, one needs to keep in mind that compared to the standardized dosing of medical treatments phototherapy is a much more complex and dynamic procedure that encompasses a variety of factors such as determination of the initial UV dose, dose increments, frequency of weekly UV exposures and total length of treatment. All these factors may have an impact on the therapeutic outcome and explain why differences in the treatment protocol make it difficult to compare phototherapeutic studies. It would have been interesting to learn whether the use of phototherapies for AD has changed within recent years but this issue was unfortunately not addressed in Steyn's electronic survey. As previous studies have shown a continuous decline in prescribing phototherapy for psoriasis, it is likely that with the advent and wide promotion of new therapeutic agents the same will happen in AD.5 A better standardization of phototherapeutic practices and high-quality clinical studies on its efficacy will be required in the future to maintain a place for phototherapy in the rapidly changing landscape of AD treatments.6 None to declare. None to declare. Data sharing not applicable to this article as no datasets were generated or analysed during the current study.