Abstract: 【Abstract】 Pyogenic arthritis, pyoderma gangrenosum and acne （PAPA） syndrome is an autosomal dominant inherited autoinflammatory disease. Its diagnosis and treatment are challenging due to the complexity of pathogenesis and diversity of clinical manifestations. In this article, a 28-year-old male patient with PAPA syndrome was reported, who presented with inflammatory papules, nodules, and cysts on the face for 6 years and repeated painful ulcers on the lower extremities for 3 years. The patient had a history of aseptic pyogenic arthritis. Histopathological findings of lower extremity lesions indicated neutrophil infiltration, and whole-exome sequencing indicated a heterozygous missense mutation c.748G>A （p.Glu250Lys） in exon 11 of the PSTPIP1 gene. The patient was finally diagnosed with PAPA syndrome. After successive treatment with glucocorticoids, cyclosporine, minocycline, and other drugs, the lesions improved, but were recurrent. Afterwards, the patient received 3-month treatment with adalimumab combined with glucocorticoids, the ulcerative skin lesions on the lower extremities markedly improved, and the facial lesions gradually subsided; the treatment lasted 1 year, and the patient′s condition was stable without recurrence.

Key words: Arthritis, Pyoderma gangrenosum, Acne vulgaris, Pyogenic arthritis, pyoderma gangrenosum and acne syndrome, Gene PSTPIP1, Adalimumab