PAPA (Pyogenic Arthritis, Pyoderma Gangrenosum, and Cystic Acne)
Pyogenic Arthritis, Pyoderma gangrenosum and Acne (PAPA) is an autoinflammatory disease. PAPA was also known as Familial Recurrent Arthritis. This is an autosomal dominant autoinflammatory disease, which means that a person only needs to inherit a gene mutation for PAPA from one parent to have the disease, or they can have a spontaneous gene mutation that can cause the syndrome.
PAPA is caused by mutation in the PSTPIP1 gene located on chromosome 15q24-q25.1. Mutations in this area are believed to cause a dysfunction in the native immune response that leads to a chronic low-level of inflammation in the body, and risk for flares of symptoms after minor (or major) injury or trauma, or stress-induced acute inflammation.
The characteristics of PAPA include an early onset of painful flares of sterile arthritis with neutrophilic infiltrates, with variable skin involvement. Patients may have ulceration, pyoderma gangrenosum, or very severe cystic acne. Elevated levels of Interleukin-1 β and Tumor Necrosis Factor (TNF alpha) have been reported to be found in peripheral blood leukocytes by some researchers. There can be joint destruction from the arthritis, and scarring on the skin from the deep skin lesions.