Diagnostic and Therapeutic Challenges in Psoriasis–Atopic Dermatitis Overlap: A Retrospective Observational Cohort Study

Background and Objectives: Psoriasis and atopic dermatitis (AD) are immune-mediated inflammatory diseases traditionally viewed as distinct. However, a subset of patients may present with overlapping features, leading to diagnostic and therapeutic challenges. This study aims to characterize the clinical, histopathological, and therapeutic features of patients with psoriasis–AD overlap. Materials and Methods: A retrospective review was conducted on patients diagnosed with both psoriasis vulgaris and AD between January 2021 and October 2024 at a single tertiary dermatology center. Inclusion required histopathological confirmation of psoriasis and a clinical diagnosis of AD based on Hanifin and Rajka criteria. Clinical features, histopathology, treatment history, and 6-month outcomes were analyzed. Results: Out of 469 patients screened, 24 (5.1%) had both conditions. Psoriasis preceded AD in 91.6% of cases. Most patients had intrinsic AD subtypes and moderate-to-severe diseases. Palmoplantar involvement was present in 66.6%, often refractory to biologics alone. Histological overlap complicated diagnosis, with repeated biopsies required in 58.3% of cases. Patients with dual diseases often required combination therapy, and JAK inhibitors showed favorable outcomes in refractory cases. Conclusions: Psoriasis–AD overlap represents a distinct clinical entity requiring individualized diagnosis and management. Recognition of this phenotype is critical for optimizing therapeutic outcomes.