What is the treatment for cellulitis?

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Last updated: February 18, 2025View editorial policy

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From the Guidelines

Cellulitis treatment typically involves a 5-day course of oral antibiotics [ 1 ], with options including cephalexin 500mg four times daily, dicloxacillin 500mg four times daily, or clindamycin 300-450mg three times daily. For more severe cases, intravenous antibiotics such as cefazolin 1-2g every 8 hours or ceftriaxone 1-2g every 24 hours may be necessary [ 1 ].

Key Considerations

  • Pain management with acetaminophen 650-1000mg every 4-6 hours or ibuprofen 400-800mg every 6-8 hours is also recommended to alleviate symptoms [ 1 ].
  • Elevating the affected limb and applying warm compresses can also help reduce swelling and promote healing [ 1 ].
  • MRSA coverage may be necessary in certain cases, such as those with penetrating trauma or purulent drainage [ 1 ].

Treatment Duration

  • The recommended duration of antimicrobial therapy is 5 days, but treatment should be extended if the infection has not improved within this time period [ 1 ].

Special Considerations

  • Outpatient therapy is recommended for patients who do not have SIRS, altered mental status, or hemodynamic instability [ 1 ].
  • Hospitalization is recommended if there is concern for a deeper or necrotizing infection, for patients with poor adherence to therapy, for infection in a severely immunocompromised patient, or for those with systemic toxicity [ 1 ].

From the FDA Drug Label

DOSAGE AND ADMINISTRATION The penicillinase-resistant penicillins are available for oral administration and for intramuscular and intravenous injection. Bacteriologic studies to determine the causative organisms and their sensitivity to the penicillinase-resistant penicillins should always be performed. Duration of therapy varies with the type and severity of infection as well as the overall condition of the patient, therefore, it should be determined by the clinical and bacteriological response of the patient In severe staphylococcal infections, therapy with penicillinase-resistant penicillins should be continued for at least 14 days. Therapy should be continued for at least 48 hours after the patient has become afebrile, asymptomatic, and cultures are negative.

The treatment for cellulitis is not explicitly mentioned in the provided drug labels. However, based on the information provided for severe staphylococcal infections, the treatment may involve:

  • Penicillinase-resistant penicillins such as dicloxacillin
  • Duration of therapy: at least 14 days for severe infections
  • Continuation of therapy: for at least 48 hours after the patient has become afebrile, asymptomatic, and cultures are negative
  • Bacteriologic studies: to determine the causative organisms and their sensitivity to the penicillinase-resistant penicillins It is essential to note that the treatment should be determined by the clinical and bacteriological response of the patient 2.

Alternatively, clindamycin may be used to treat serious infections due to anaerobic bacteria, with a dosage of 150 to 300 mg every 6 hours for adults with serious infections 3.

From the Research

Treatment Overview

The treatment for cellulitis typically involves antibiotic therapy, with the goal of eliminating the underlying bacterial infection.

  • The recommended duration of antibiotic therapy can vary, but studies suggest that a course of 5-14 days is common 4.
  • The route of antibiotic administration, whether intravenous (IV) or oral (PO), may depend on the severity of the infection, with IV therapy often preferred for more severe cases 5.

Antibiotic Duration and Route

Research has investigated the optimal duration and route of antibiotic therapy for cellulitis:

  • A study found that 5 days of therapy with levofloxacin was as effective as 10 days of therapy for patients with uncomplicated cellulitis 6.
  • Another study compared 6 days of antibiotic treatment to 12 days and found that the shorter course resulted in more frequent relapses by day 90, although the difference in cure rates was not significant 7.
  • The choice between IV and PO antibiotic therapy may not significantly impact clinical outcome, with one study finding that patients who received only PO therapy were more likely to improve at day 5 compared to those who received at least one dose of IV therapy 5.

Factors Influencing Treatment

Several factors can influence the duration and effectiveness of antibiotic therapy for cellulitis:

  • Patient age, C-reactive protein levels, and the presence of diabetes mellitus or bloodstream infection can affect the duration of treatment 4.
  • The severity of the infection, as measured by factors such as affected skin surface area and systemic inflammatory response syndrome score, can influence the choice of antibiotic therapy and duration of treatment 5.

Clinical Guidelines

Current practice guidelines recommend targeted antibiotic coverage for the most common pathogens causing cellulitis, including β-hemolytic streptococci and methicillin-sensitive Staphylococcus aureus:

  • Oral antibiotics such as penicillin, amoxicillin, and cephalexin are often sufficient for non-purulent, uncomplicated cases of cellulitis 8.
  • Coverage for community-acquired methicillin-resistant Staphylococcus aureus is generally not recommended for non-purulent cellulitis 8.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Factors that affect the duration of antimicrobial therapy for cellulitis.

Journal of infection and chemotherapy : official journal of the Japan Society of Chemotherapy, 2018

Research

Antibiotic treatment for 6 days versus 12 days in patients with severe cellulitis: a multicentre randomized, double-blind, placebo-controlled, non-inferiority trial.

Clinical microbiology and infection : the official publication of the European Society of Clinical Microbiology and Infectious Diseases, 2020

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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