fasciitis fasciitis fasciitis is an inflammation of the fascia, which is the connective tissue surrounding muscles, blood vessels and nerves. fasciitisfasciapronunciation/ˌfæʃiˈaɪtɪs/ specialtyrheumatology in particular, it often involves one of the following diseases: necrotizing fasciitis plantar fasciitis ischemic fasciitis, classified by the world health organization, 2020, as a specific tumor form in the category of fibroblastic and myofibroblastic tumors. eosinophilic fasciitis paraneoplastic fasciitis