A: The most common infectious cause of limb swelling, cellulitis is an infection of the subcutaneous layer of the skin. It may follow damage, such as a bite or wound, and can happen as a single event or a series of recurrent events. Cellulitis occurs when bacteria enter the normal skin barrier, releasing toxins into surrounding tissue. As the organism invades the area, it overwhelms the defensive cells (neutrophils, eosinophils, basophils, and mast cells) that break down the cellular components, which normally contain and localize the inflammation. As cellulitis progresses, the organism invades tissue around the initial wound site. Risk factors for cellulitis include diabetes, immunodeficiency, impaired circulation, and neuropathy.
The classic signs of cellulitis are acute onset of swelling (edema) and localized redness (erythema) surrounding the initial wound (see Recognizing cellulitis). The site is usually warm and painful to the touch, and the patient may experience fever, chills, and sweating. Regional lymph nodes may also be tender and enlarged.
Cellulitis is often misdiagnosed, usually as recurrent thrombophlebitis or chronic venous insufficiency. Mild cases of cellulitis can be treated on an outpatient basis with oral antibiotic therapy. If the case is severe, the patient is treated with I.V. antibiotics for at least 7 to 14 days. The key to preventing recurrent episodes of cellulitis is adequate antibiotic therapy for the initial event and identifying the site of bacterial entry. The most commonly overlooked areas are the cracks and fissures that occur in the skin between the toes. Other possible locations are injection sites, contusions, abrasions, ulcerations, ingrown toenails, and hangnails.
Instruct the patient to elevate the affected area above heart level and apply warm, moist packs to the site every 2 to 4 hours. Patients with sensory and circulatory deficits, such as those caused by diabetes or paralysis, should use caution when applying warm packs because burns may occur. Focus patient education on preventing a recurrent episode. And educate the patient with peripheral vascular disease or diabetes about the importance of skin and foot care.
If cellulitis is treated in a timely manner, the prognosis is usually good. And now you know what to look for.
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