What are the characteristic features and treatment of cellulitis?

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Last updated: June 28, 2025View editorial policy

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From the Guidelines

Cellulitis is a common bacterial skin infection characterized by redness, swelling, warmth, tenderness, and pain in the affected area, and its treatment primarily involves antibiotics, with a recommended duration of 5 days, but can be extended if the infection has not improved within this time period, as stated in the guidelines by the Infectious Diseases Society of America 1. The characteristic features of cellulitis include poorly demarcated erythema that spreads over hours to days, often accompanied by fever, chills, and malaise. The most common causative organisms are Streptococcus and Staphylococcus bacteria, which enter through breaks in the skin such as cuts, wounds, or dermatological conditions. Some key points to consider in the treatment of cellulitis include:

  • Oral antibiotics such as cephalexin, dicloxacillin, or clindamycin are suitable for mild cases, while severe cases require intravenous antibiotics such as cefazolin, nafcillin, or vancomycin in a hospital setting 1.
  • Elevation of the affected limb to reduce swelling, pain management with acetaminophen or ibuprofen, and keeping the area clean and dry are important supportive measures 1.
  • Patients should seek immediate medical attention if they develop high fever, increasing pain, red streaking from the infection site, or if the area becomes significantly more swollen or hard, as these may indicate worsening infection or complications such as abscess formation or sepsis.
  • Prevention involves proper wound care, regular handwashing, and prompt treatment of skin injuries or conditions that compromise skin integrity. It is essential to note that the treatment of cellulitis should be individualized based on the patient's clinical response, and the recommended duration of antimicrobial therapy is 5 days, but can be extended if the infection has not improved within this time period, as stated in the guidelines by the Infectious Diseases Society of America 1.

From the Research

Characteristic Features of Cellulitis

  • Cellulitis is an acute infection of the dermal and subcutaneous layers of the skin, often occurring after a local skin trauma 2.
  • It classically presents with erythema, swelling, warmth, and tenderness over the affected area 2, 3, 4.
  • The clinical presentation 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 3, 4, 5.

Treatment of Cellulitis

  • Most patients can be treated as an outpatient with oral antibiotics, with dicloxacillin or cephalexin being the oral therapy of choice when methicillin-resistant Staphylococcus aureus is not a concern 2.
  • Treatment of primary and recurrent cellulitis should initially cover Streptococcus and methicillin-sensitive S. aureus, with expansion for methicillin-resistant S. aureus (MRSA) in cases of cellulitis associated with specific risk factors 3.
  • Five days of treatment is sufficient with extension if symptoms are not improved 3.
  • Antibiotics with activity against community-associated MRSA, such as trimethoprim-sulfamethoxazole and clindamycin, are preferred empiric therapy for outpatients with cellulitis in the community-associated MRSA-prevalent setting 6.
  • Novel antimicrobial agents registered for cellulitis are also discussed in recent literature 5.

Diagnosis and Management

  • The diagnosis of cellulitis is based primarily on history and physical examination 3, 4.
  • History, local characteristics of the affected area, systemic signs, laboratory tests, and, in some cases, skin biopsy can be helpful in confirming the correct diagnosis 2.
  • Microbiological diagnosis is often unobtainable due to poor sensitivity of culture specimens 4.
  • Recent evidence on diagnostic strategies is discussed, highlighting the importance of distinguishing cellulitis from other conditions such as venous insufficiency, eczema, deep vein thrombosis, and gout 5.

References

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Research

Cellulitis: diagnosis and management.

Dermatologic therapy, 2011

Research

Cellulitis: A Review.

JAMA, 2016

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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