Is neutrophilic dermatosis a manifestation of familial Mediterranean fever?

Objectives: Familial Mediterranean fever (FMF) is the most frequent monogenic autoinflammatory disease. It is associated with MEFV mutations. Its main features are recurrent episodes of fever and serositis. Patients can display dermatological manifestations such as erysipelas-like erythema, generally considered as a neutrophilic dermatosis (ND). It has been suggested that FMF can be associated with other types of ND. Our aim was to perform a systematic review of the literature to assess the link between ND and FMF. Method: A systematic review of the literature was performed using MEDLINE from 1946 to 2018. Three independent investigators identified reports of non-erysipelas-like erythema neutrophilic dermatosis (NEND) associated with FMF, selected the criteria to establish the diagnosis of FMF and ND, and evaluated the link between the two conditions. FMF-associated NEND was supported by confirmation of both diagnoses and exclusion of other causes of ND. Results: Eighteen articles were selected. Nine articles reported FMF patients with the following NEND: neutrophilic panniculitis (n = 4), Sweet syndrome (n = 6), and pyoderma gangrenosum (n = 1). None of these cases was supported by histological confirmation, fulfilled diagnostic criteria for definitive or probable FMF, or confirmed the exclusion of all the most frequent diseases associated with NEND. As a result, there is insufficient evidence to support a potential relationship between NEND and FMF. Conclusions: The association between FMF and NEND remains unclear. In FMF patients with NEND, every differential diagnosis and alternative cause of NEND should be excluded before drawing any conclusions about a potential causal relationship.