Effectiveness and safety of phototherapy in geriatric psoriasis: a retrospective multicenter study

Abstract Managing psoriasis in elderly individuals is challenging because of the presence of multiple comorbidities and the use of concurrent medications. Although phototherapy is preferred, studies comparing its use in elderly versus younger patients are limited. This study aimed to compare the effectiveness, safety, and adherence to phototherapy between elderly (≥ 60 years) and nonelderly psoriasis patients and to identify factors associated with remission and adverse effects. We retrospectively reviewed the records of psoriasis patients who received whole-body narrowband ultraviolet B phototherapy between January 2007 and June 2021 at three phototherapy centers in Thailand. A total of 397 patients were included, with 73 patients (18.4%) in the elderly group. Elderly patients had significantly higher rates of various comorbidities, but not psoriatic arthritis or nail involvement. The phototherapy protocols used were similar for both groups. Elderly patients had slightly higher baseline Psoriasis Area and Severity Index (PASI) scores (8.3 vs. 7.6) and required more phototherapy sessions (41 vs. 34); however, the percentage improvement in the PASI score was comparable (64.4% vs. 67.9%). Elderly patients had significantly fewer burning side effects (6.8% vs. 19.8%, P = 0.009). Phototherapy combined with acitretin was associated with increased burning side effects. In multivariate analysis, a lower starting phototherapy dose (< 330 mJ/cm²) was associated with a higher likelihood of psoriasis remission. In conclusion, phototherapy is as effective in elderly psoriasis patients as in younger patients and is associated with fewer side effects. It remains a safe and effective treatment option for elderly individuals with psoriasis.