Phlegmon is an unbounded and aggressively spreading infection of soft tissues. Mostly we talk about phlegmon of limbs and some organs.


The most common cause of purulent inflammations of the skin and deeper tissues are bacteria from the group of streptococci. While staphylococci tend to form a bounded inflammation, the streptococci spread. Phlegmon may arise after penetration of streptococci through a previously healthy skin (e.g. after an injury) or it develops from other preexisting streptococcal skin infections (such as erysipelas). Phlegmon occurrence is more frequent in patients with weakened immunity.


The affected part of the body (usually an extremity) is swollen, red, warm and usually significantly painful when palpated. Abscesses (cavities filled with pus) may arise as the immune system tries to surround the infection and stop it from further spreading. The process is accompanied by high fever and other signs of infection. Phlegmon may easily cause a sepsis with progression into a life-threatening shock.


Phlegmonous inflammation can be easily diagnosed by physical examination. The extent of inflammation and deep abscesses may be visualized by ultrasonography or computed tomography. Blood tests show us elevated number of white blood cells and elevated CRP.


Patients with phlegmon should be certainly hospitalized and cautiously treated. Antibiotics are the therapy of choice and in addition, the patient must be hydrated and monitored to prevent the occurrence of septic shock. In more severe cases, surgical intervention is needed including revision of affected tissues and draining the pus. If the condition is unsolvable by the above mentioned means, amputation of the affected body part may be necessary.


Jiri Stefanek, MD  Author of texts: Jiri Stefanek, MD
 Sources: basic text sources