The term flesh-eating bacteria refers to an infection called necrotizing faciitis. This is a severe, rapidly progressive bacterial infection of the skin and underlying soft tissues and muscle compartment sheath (the fascia). Necrotizing faciitis causes a deep open wound that quickly expands, which is why people call this infection flesh-eating bacteria. In reality, the flesh is not being eaten, but rather it is dying because of the infection. The bacteria cause the small blood vessels in the infected area to clot off, shutting down the blood supply. Without a blood supply, the tissues die and decay--a process called necrosis.
Necrotizing fasciitis is often caused by group A streptococci, although other bacteria may cause the condition as well. This infection is rare but potentially life-threatening. Early recognition of symptoms and immediate medical care are critical.
Pain
Necrotizing faciitis is usually associated with an injury or wound. A cut, scrape, bruise, burn, insect bite or surgical incision typically provides entry for the invading bacteria. Severe pain---far more severe than expected for the injury---is an early symptom of an evolving case of necrotizing fasciitis. The pain often escalates prior to the development of an open sore. Notably, once the infection has progressed to the point of causing tissue death, the pain usually recedes as the nerves in the affected area are also dying.
Local Skin Warmth
The skin over the infected area is hot to the touch and initially appears red. The warm area enlarges as the infection spreads. Be aware that the coloration of the skin typically changes from red to purple to dusky gray as the overlying skin dies.
Swelling
The infected area is swollen. The overlying skin is taut and shiny. The swelling rapidly advances outward as the infection spreads. Necrotizing fasciitis progresses so quickly that a noticeable expansion of the swelling may take place in as little as 30 minutes.
Blisters
Raised blisters may develop on the affected skin, depending on the type of bacteria causing the infection. A crackling or popping sensation or sound produced when pressing on the skin may accompany the blister formation. This symptom is called crepitus.
Ulceration
An opening in the skin develops as the overlying skin of the affected area dies. The ulcer rapidly grows as the infection progresses. Opaque fluid usually oozes from the ulcer.
Foul Odor
Skin and soft tissues are dying as necrotizing fasciitis progresses. This typically produces a foul odor emanating from the wound.
High Fever
High fever accompanies necrotizing fasciitis, typically 102 to 105 degrees F (38.9 to 40.6 degrees C). Chills and sweating are common.
Malaise
People with necrotizing fasciitis feel quite ill, a symptom known as malaise. Common complaints include extreme fatigue, nausea, headache and generalized weakness.
Dizziness
The systemic effects of necrotizing fasciitis cause low blood pressure, which commonly leads to dizziness or fainting.
Heart Palpitations
The combined effects of the infection and the high fever cause an increased heart rate. The rapid heart rate triggers an awareness of the bounding heartbeat. This symptom is called heart palpitations. It may be a harbinger of impending cardiovascular collapse.
Altered Mental State
The toxic effects of the bacteria often cause confusion, disorientation or mental dullness. In cases where the bacteria spread to the bloodstream, shock usually develops and may lead to coma.
References
- Merck Manuals: Necrotizing Subcutaneous Infection
- "Principles and Practice of Infectious Diseases, Sixth Edition"; Gerald L. Mandell, M.D., John E. Bennett, M.D., Raphael Dolin, M.D.; 2004
- MedlinePlus: Necrotizing Soft Tissue Infection
- Merck Manuals: Necrotizing Skin Infections
- Centers for Disease Control and Prevention: Group A Streptococcal (GAS) Disease
