GENERAL PRINCIPLES

Cellulitis and lymphangitis

Cellulitis is a superficial, spreading infection of the skin and subcutaneous tissue and usually follows lacerations and surgical wounds.

The most common causative organism is penicillin sensitive streptococci. Cellulitis is characterized by signs of inflammation (local pain, tenderness, swelling and erythema). The border between involved and uninvolved skin is usually indistinct and systemic illness characterized by fever, chills, malaise and toxicity is frequently present.

Lymphangitis is inflammation which tracks along the lymphatics in the subcutaneous tissues. Treat cellulitis and lymphangitis with antibiotics. Failure to respond to antibiotics suggests abscess formation, which requires surgical drainage.

Abscess

Treat abscess cavities with incision and drainage to remove accumulated pus. Diagnose by the presence of one or more of the following signs: extreme tenderness, local heat and swelling causing tight, shiny skin. Fluctuation is a reliable sign when present, although its absence does not rule out a deep abscess or an abscess in tissues with extensive fibrous components. These tissues include the breast, the perianal area and finger tips. Be suspicious of deep throbbing pain or of pain which interferes with sleep.

Technique

1	If in doubt about the diagnosis of abscess, confirm the presence of pus with needle aspiration. Prepare the skin with antiseptic, and give adequate anaesthesia. A local anaesthetic field block infiltrating uninfected tissue surrounding the abscess is very effective. Perform the preliminary aspiration using an 18 gauge or larger needle to confirm the presence of pus (Figure 5.28). Make an incision over the most prominent part of the abscess or use the needle to guide your incision. Make an adequate incision to provide complete and free drainage of the cavity. An incision which is too small, will lead to recurrence.
	Figure 5.28
2	Introduce the tip of a pair of artery forceps into the abscess cavity and open the jaws (Figure 5.29). Explore the cavity with a finger to break down all septa (Figure 5.30).
	Figure 5.29
	Figure 5.30
3	Extend the incision if necessary for complete drainage (Figure 5.31), but do not open healthy tissue or tissue planes beyond the abscess wall.
	Figure 5.31
4	Culture the abscess wall. Give antibiotics for cutaneous cellulitis, fever or if the abscess involves the hand, ear or throat.
5	Irrigate the abscess cavity with saline and drain or pack open. The objective is to prevent the wound edges from closing, allowing healing to occur from the bottom of the cavity upward. To provide drainage, place a latex drain into the depth of the cavity. Fix the drain to the edge of the wound with a suture and leave in place until the drainage is minimal.
6	Alternatively, pack the cavity open, place several layers of damp saline or petroleum gauze in the cavity leaving one end outside the wound. Control bleeding by tight packing.