Pyoderma gangrenosum, acne, and suppurative hidradenitis (PASH)–a new autoinflammatory syndrome distinct from PAPA syndrome

Background PAPA syndrome is a recently identified hereditary autoinflammatory syndrome clinically characterized by pyogenic arthritis, severe acne, and pyoderma gangrenosum. It is caused by mutations in the PSTPIP1 gene and may be closely linked to the aseptic abscesses syndrome, which has been shown to be associated with CCTG repeat amplification in the promoter region of PSTPIP1. Objective We describe two unrelated patients with a clinical presentation quite similar to, yet distinct from, PAPA syndrome. Results Both patients had pyoderma gangrenosum and acute or remittent acne conglobata, but, in contrast to PAPA syndrome, lacked any episodes of pyogenic arthritis. Instead, they had suppurative hidradenitis. Mutations in PSTPIP1 exons 1 to 15 were excluded. In the promoter region, an increased repetition of the CCTG microsatellite motif was present on one allele in both patients. Alterations of the most commonly affected exons of the MEFV , NLRP3 , and TNFRSF1A genes also were not detectable. One patient was treated with the interleukin (IL)-1 receptor antagonist anakinra and responded well, although without complete remission. This implies that IL-1ß may be of pathogenetic importance. Limitations Small number of patients, no gene mutation identified, and unclear efficacy of therapy are limitations. Conclusions The clinical triad of pyoderma gangrenosum, acne, and suppurative hidradenitis represents a new disease entity within the spectrum of autoinflammatory syndromes, similar to PAPA and aseptic abscesses syndrome. For this disease, we propose the acronym “PASH” syndrome. PASH syndrome may respond to IL-1ß blockade.