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 has been infrequently documented in the literature. Consequently, this study aimed to analyze this entity from our tertiary center and review the relevant literature.

Methods: This retrospective observational cross-sectional study and case series included patients with DM/CADM and psoriasis between 1998 and 2024. A 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 revealed that six patients were discharged, two died, and one continued follow-up. The primary 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 the literature review, 15 articles reported a total of 17 cases of overlapping DM/CADM and psoriasis. However, variability was observed in the DM/CADM diagnostic criteria. The mean age at DM diagnosis in the literature was 32.3 years (range: 2-59), whereas for psoriasis, it was 31 (7-63) years. Female patients were predominant.

Conclusion: This investigation identified the coexistence of DMPs, with a median age of 38 years for DM and 43 years for psoriasis. The variability in the diagnostic criteria underscores the necessity for standardized approaches to enhance patient management.