Clinical Characteristics and Disease Burden of Patients with Moderate-to-Severe Generalized Pustular Psoriasis Flares in Taiwan.

Introduction: Generalized pustular psoriasis (GPP) is a rare and severe psoriasis subtype characterized by the rapid onset of coalescing sterile pustules over broad body areas and systemic inflammation. Data on its clinical course and outcomes in Taiwan are limited. We evaluated the clinical profile and outcomes of patients with GPP flares in Taiwan.

Methods: This retrospective analysis included adult patients with moderate-to-severe GPP flares occurring in January 2008-December 2021. Data were extracted from medical charts and electronic health records in the Chang Gung Research Database. Statistical analyses were performed using SAS for Windows (version 9.4). Multivariate Poisson regression models were built to investigate different predictors of GPP flare rate.

Results: Thirty-four patients with 81 moderate-to-severe GPP flares were identified. Of the 14 patients undergoing genetic analysis, 10 (71.4%) had an IL36RN mutation. Patients' mean age at the index GPP flare was 47.1 ± 16.5 years; 58.0% of the flares were severe, while 42.0% were moderate. Overall, 96.3% of GPP flares were treated with at least one systemic therapy, acitretin being the most prescribed (85.2%), followed by cyclosporine (45.7%) and methotrexate (18.5%). After treatment, the proportion of flares responding positively increased from 0% on day 2 to 6.2% by week 12. Patients were newly diagnosed with psoriasis (23.5%), hypertension (20.6%), diabetes mellitus (14.7%), psoriatic arthritis (2.9%), malignant tumor (8.8%), and depression/anxiety (2.9%) after enrollment. Complications occurring within 12 weeks of GPP flares included arthritis (25.9% of the flares), skin infection (8.6%), and other infections (2.5%). No fatalities were reported. In the multivariate model, former smokers, patients with hepatic disease, and patients with psoriatic arthritis had an increased GPP rate ratio (RR) of 13.33 (95% confidence interval, CI, 2.87-61.78), 14.08 (95% CI 3.04-65.29), and 34.84 (95% CI 4.77- 254.42), respectively. Contrarily, obese and rheumatoid arthritis patients had a lower GPP rate ratio of 0.21 (95% CI 0.08-0.54) and 0.07 (95% CI 0.006-0.78), respectively.

Conclusions: Our findings highlight the complexity of GPP flare presentations and the need for individualized, patient-centered management approaches and continued research to improve affected individuals' care and outcomes.