Patients with overlapping dermatomyositis and psoriasis: An experience from a tertiary center and review of the literature

Background The coexistence of dermatomyositis (DM)/clinically amyopathic DM (CADM) and psoriasis is rare, and has been described in a few case reports. Therefore, this study aimed to analyze this entity from our tertiary center and review the relevant literature. Methods This retrospective observational cohort study included patients with DM/CADM and psoriasis between 1998 and 2024. A systematic literature review was also conducted. Results Nine of 331 patients with DM (n = 265)/CADM (n = 66) had psoriasis; six were female, and all were of white ethnicity. The median age at DM diagnosis was 38 years (range: 18–78), and at psoriasis diagnosis was 43 years (range: 18–81), with a median interval of four years between diagnoses. The follow-up showed that six patients were discharged, two died, and one continued follow-up. The main comorbidities included systemic arterial hypertension (n = 3) and diabetes mellitus (n = 3). Four patients presented with varicella zoster (n = 1) or pulmonary tuberculosis (n = 3). Regarding literature review, there were 15 articles that reported a total of 17 cases of overlapping DM/CADM and psoriasis. However, variability was observed in the DM/CADM diagnostic criteria. The average age at DM diagnosis in the literature was 32.3 years (range: 2–59), whereas psoriasis was an average of 31 (7–63) years. Female patients were predominant. Conclusion This investigation identified the rare coexistence of DMPs, revealing older age at diagnosis ages and a higher prevalence of CADM among DM patients. With a median age of 38 years for DM and 43 years for psoriasis, our findings align with those in the existing literature. However, variability in the diagnostic criteria highlights the need for standardized approaches to improve patient management.