Fournier gangrene is a localized variant of necrotizing fasciitis involving the scrotum and penis. It is usually caused by the same mix of facultative and anaerobic organisms that are associated with type I necrotizing fasciitis. In rare cases, GAS as the single pathogen has been implicated, and this may be related to rectal ring carriage or to oral-genital sex. The average age at onset is 50 to 60 years of age. Most men have underlying diseases or history of procedures. These include diabetes mellitus, ischiorectal abscess, perineal fistula, bowel disease (rectal or colon carcinoma, diverticulitis), scrotal or penile trauma, prior hemorrhoidal or urogenital surgery, pressure ulcers of the scrotum and perineum (e.g., alcoholics sitting in a drunken stupor), paraphimosis and, rarely, obscure causes, such as dissection of pancreatic secretions through the retroperitoneum and into the scrotum in acute pancreatitis.
The onset of Fournier gangrene can be insidious, with a discrete area of edema, erythema, and necrosis on the scrotum, progressing to advancing skin necrosis rapidly over 1 to 2 days . Pain, swelling, and crepitus in the scrotum, perineum, or suprapubic region may be marked. Foul-smelling drainage occurs, indicating a contribution from anaerobes. Purplish discoloration of the scrotum, an initial “red flag,” progresses to frank gangrene. The infection tends to be superficial, limited to skin and subcutaneous tissue and extending to the base of the scrotum, but it may spread to the penis, perineum, and abdominal wall along fascial planes. The testes, glans penis, and spermatic cord are usually spared, as they have a separate blood supply. The infection may progress and invade the abdominal panniculus in obese patients, especially those with diabetes mellitus, leading to rapid and extensive destruction of tissue and requiring wide débridement and prolonged hospitalization.
Cervical Necrotizing Fasciitis and Craniofacial Necrotizing Fasciitis.
Cervical necrotizing fasciitis is a type I infection (polymicrobial etiology), but GAS can be the single etiologic agent in rare cases, particularly in the setting of peritonsillar abscess formation. Most commonly, cervical necrotizing fasciitis originates from dental or pharyngeal sources. Crepitus may develop as the infection spreads to the face. This is in contradistinction to necrotizing fasciitis that starts in the face (craniofacial necrotizing fasciitis), which is most commonly caused by GAS after a traumatic episode. Cervical necrotizing fasciitis carries a much higher mortality rate than the craniofacial variant.