Cellulitis

Cellulitis is usually a bacterial infection involving the inner layers of the skin. It specifically affects the dermis and subcutaneous fat. Signs and symptoms include an area of redness that increases in size over a few days. The borders of the area of redness are generally not sharp, and the skin may be swollen. While the redness often turns white when pressure is applied, this is not always the case. The area of infection is usually painful. Lymphatic vessels may occasionally be involved, and the person may have a fever and feel tired. The legs and face are the most common sites involved, although cellulitis can occur anywhere on the body. The leg is typically affected following a break in the skin from abrasions, arthropod bites, or maceration between the toes. Other risk factors include obesity, leg swelling, and old age. For facial infections, a break in the skin beforehand is not usually the case. The bacteria most commonly involved are streptococci and Staphylococcus aureus. In contrast to cellulitis, erysipelas is a bacterial infection involving the more superficial layers of the skin, present with an area of redness with well-defined edges, and is more often associated with a fever. The diagnosis is usually based on the presenting signs and symptoms, while a cell culture is rarely possible. Before making a diagnosis, more serious infections such as an underlying bone infection or necrotizing fasciitis should be ruled out. Treatment is typically with antibiotics taken by mouth, such as cephalexin, amoxicillin or cloxacillin. Those who are allergic to penicillin may be prescribed erythromycin or clindamycin instead. When methicillin-resistant S. aureus (MRSA) is a concern, doxycycline or trimethoprim/sulfamethoxazole may, in addition, be recommended. There is concern related to the presence of pus or previous MRSA infections. Elevating the infected area may be useful,...