Cellulitis describes an inflammation of the outer layer of skin, known as the dermis. The condition is related to an acute infection that has not spread to deeper tissues. It typically presents with local pain, swelling, tenderness, redness and warmth. Antibiotic drugs used to treat cellulitis aim to eradicate the infection and prevent complications.
Mild Cellulitis
Oral antibiotic medications treat mild cases of cellulitis. The medications include agents that work against staphylococci and streptococci, the two most common bacteria causing this disease. Penicillins such as dicloxacillin may be prescribed, or a doctor may use cephalosporins such as cephalexin. Other drugs that are sometimes used, especially in people with a penicillin allergy, are clindamycin, erythromycin and levofloxacin. Treatment duration is usually about one week.
Severe Cellulitis
Cellulitis can be more severe, causing symptoms such as fever, malaise and toxicity. When these symptoms develop, urgent antibiotic administration is needed, likely requiring a longer course of treatment. Oxacillin and nafcillin are used for the severe infections. Sometimes, despite appropriate antibiotic care, the infection gets worse. An especially dangerous consequence is when the infection spreads to deeper skin layers or into the blood. If the infection worsens despite the use of those medications, or if it spreads beyond the superficial skin layers, appropriate therapy may also require intravenous antibiotics, such as cefazolin, to be administered in the hospital.
Antibiotic-Resistant Cellulitis
Many forms of bacteria that cause common infections have developed a resistance to commonly used antibiotics. An example of this is methicillin-resistant staphylococcus aureus (MRSA), which can cause cellulitis. Standard antibiotics may not be effective for infections with that organism. Drugs used in those cases include trimethoprim/sulfamethoxazole (Bactrim), vancomycin (in IV form) and linezolid (in oral or IV form). These medications have proved effective for most cases of resistant bacterial infections.
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