What is the treatment for cellulitis (infection of the skin and subcutaneous tissues)?

From the Guidelines

Cellulitis is a bacterial skin infection that requires oral or intravenous antibiotics for treatment, and cream is not a recognized or effective treatment for this condition. The most recent and highest quality study, 1, recommends that therapy for typical cases of cellulitis should include an antibiotic active against streptococci, such as penicillin, amoxicillin, amoxicillin-clavulanate, dicloxacillin, cephalexin, or clindamycin.

Key Points to Consider

• The infection is in the deeper skin layers, where topical medications cannot effectively reach, as noted in 1 and 1.
• Suitable antibiotics for most patients include penicillin, amoxicillin, amoxicillin-clavulanate, dicloxacillin, cephalexin, or clindamycin, as stated in 1.
• A 5-day course of antimicrobial therapy is as effective as a 10-day course if clinical improvement has occurred by 5 days, according to 1.
• Elevation of the affected area and treatment of predisposing factors, such as edema or underlying cutaneous disorders, are recommended, as mentioned in 1 and 1.
• Patients with cellulitis should monitor for spreading redness, fever, or increasing pain, which would indicate worsening infection requiring immediate medical attention, as emphasized in 1.

Treatment Approach

• First-line treatment typically includes oral antibiotics, such as cephalexin 500mg four times daily for 5-10 days, or clindamycin 300mg four times daily if the patient has a penicillin allergy, as recommended in 1.
• Severe cases may require intravenous antibiotics like ceftriaxone 1-2g daily, as noted in 1 and 1.
• While topical antibiotics like mupirocin or retapamulin may be used for minor skin infections like impetigo, they cannot penetrate deeply enough to treat true cellulitis, as stated in 1.

From the FDA Drug Label

Clindamycin is also indicated in the treatment of serious infections due to susceptible strains of streptococci, pneumococci, and staphylococci Anaerobes: Serious skin and soft tissue infections; Streptococci: Serious skin and soft tissue infections. Staphylococci: Serious respiratory tract infections; serious skin and soft tissue infections. infections of the female pelvis and genital tract such as endometritis, nongonococcal tubo-ovarian abscess, pelvic cellulitis, and postsurgical vaginal cuff infection.

Cream cellulitis is not explicitly mentioned in the provided drug labels. However, pelvic cellulitis is mentioned as an indication for clindamycin. Since cellulitis is a type of skin and soft tissue infection, and clindamycin is indicated for the treatment of serious skin and soft tissue infections, it can be inferred that clindamycin may be used to treat cellulitis, including cream cellulitis, if caused by susceptible bacteria. However, the dosage and administration for cream cellulitis are not specified in the provided drug labels. The recommended dosage for clindamycin is 150 to 300 mg every 6 hours for serious infections, and 300 to 450 mg every 6 hours for more severe infections 2. For dicloxacillin, the recommended dosage is 125 mg every 6 hours for mild to moderate infections, and 250 mg every 6 hours for severe infections 3. It is essential to note that the treatment of cellulitis should be based on the severity of the infection, the causative organism, and the patient's overall condition. Bacteriologic studies should be performed to determine the causative organisms and their susceptibility to the antibiotic 2. The treatment should be continued for at least 48 hours after the patient has become afebrile, asymptomatic, and cultures are negative 3.

From the Research

Definition and Diagnosis of Cellulitis

• Cellulitis is a clinical diagnosis based on the history of present illness and physical examination, and it lacks a gold standard for diagnosis 4.
• The clinical presentation of cellulitis typically includes acute onset of redness, warmth, swelling, and tenderness and pain 4.
• Cellulitis can be difficult to diagnose due to a number of infectious and non-infectious clinical mimickers such as venous stasis dermatitis, contact dermatitis, eczema, lymphedema, and erythema migrans 4.

Causes and Treatment of Cellulitis

• The majority of non-purulent, uncomplicated cases of cellulitis are caused by β-hemolytic streptococci or methicillin-sensitive Staphylococcus aureus 4.
• Appropriate targeted coverage of this pathogen with oral antibiotics such as penicillin, amoxicillin, and cephalexin is sufficient for treatment 4.
• However, the use of cephalexin plus trimethoprim-sulfamethoxazole compared to cephalexin alone did not result in higher rates of clinical resolution of cellulitis in one study 5.
• Another study found that trimethoprim-sulfamethoxazole had a higher treatment success rate than cephalexin for outpatients with cellulitis, especially in areas with a high prevalence of community-associated methicillin-resistant Staphylococcus aureus (MRSA) infections 6.

Management and Prevention of Cellulitis

• Antibiotic selection is determined by patient history and risk factors, severity of clinical presentation, and the most likely microbial culprit 7.
• Local susceptibility patterns should guide empiric therapy, and agents recommended for MRSA should be used for this indication 8.
• Further studies are needed to resolve treatment dilemmas and determine the best approach for managing cellulitis, including the use of pharmacokinetic and pharmacodynamic principles to predict clinical outcome 8.