Differential diagnosis of necrotizing myositis and fasciitis

* Type I and type II refer to the forms of necrotizing fasciitis; spontaneous gangrenous myositis is type II.
¶ Pain with influenza consists of diffuse myalgia; pleurodynia may be associated with severe, localized pain (eg, devil's grip); pain with trichinosis may be severe and localized.
Δ Severe pain is associated with necrotizing fasciitis due to group A streptococcal infection; the pain may not be severe in type I necrotizing fasciitis because it is commonly associated with diabetes with neuropathy.
◊ 50% of patients with necrotizing fasciitis due to group A streptococcal infection do not have an obvious portal of entry.
§ Gas gangrene associated with trauma may be caused by Clostridium perfringens, C. septicum, or C. histolyticum, which always have an obvious portal of entry; in comparison, spontaneous gas gangrene caused by C. septicum usually does not have an obvious portal of entry (organisms lodge in tissue as a result of bacteremia originating from a bowel portal of entry).