Overlap of Psoriatic Arthritis and Dermatomyositis

Concurrence of dermatomyositis and psoriasis: a case report and literature review

Dermatomyositis (DM) is a type of inflammatory myopathy with unknown causes. It is characterized by distinct skin lesions, weakness in the muscles close to the body, and the potential to affect multiple organs. Additionally, it may be associated with the presence of malignancies. The development of DM is influenced by genetic susceptibility, autoimmune response, and various external factors like cancer, drugs, and infectious agents. Psoriasis is a chronic, recurring, inflammatory, and systemic condition. Scaly erythema or plaque is the typical skin manifestation. The etiology of psoriasis involves genetic, immune, environmental and other factors. It is uncommon for a patient to have both of these diseases simultaneously, although individuals with DM may occasionally exhibit symptoms similar to those of psoriasis. Our patient was diagnosed with psoriasis in his 50s because of scalp squamous plaques, but he did not receive standard treatment. Ten years later, he developed symptoms of muscle pain and limb weakness. He was diagnosed with psoriasis complicated with dermatomyositis in our department and received corresponding treatment. Moreover, we reviewed the relevant literature to evaluate similarities and differences in clinical manifestation and treatment to other cases.

JAK Inhibitors as Potential Therapeutic Strategy for the Dilemma of Psoriasis Concurrent with Dermatomyositis in the SARS-CoV-2 Era

Dermatomyositis is a rare inflammatory disease with potentially life-threatening systemic involvement that is treated with systemic corticosteroids. However, when psoriasis coexists with dermatomyositis, the administration of corticosteroids may exacerbate psoriasis after withdrawal, posing a treatment dilemma. Our search of the literature revealed 14 cases where various treatments were used, including methotrexate, corticosteroids, cyclosporin, ustekinumab, mycophenolate mofetil, and azathioprine. While methotrexate showed promise, it carries risks, and corticosteroids were used despite their potential to exacerbate psoriasis. Based on transcriptomic data analysis of psoriasis and dermatomyositis, the type II interferon-mediated signaling pathway was enriched in both diseases. Medication targeting this pathway, such as JAK inhibitors, could be a potential solution for the psoriasis concurrent with dermatomyositis dilemma, as JAK inhibitors have been proven effective in treating both dermatomyositis and psoriasis, with some being FDA-approved for treating COVID-19. Therefore, JAK inhibitors may be a potential therapeutic strategy for psoriasis concurrent with dermatomyositis in the SARS-CoV-2 era.