Guideline sources The following summarized guidelines for the evaluation and management of cellulitis are prepared by our editorial team based on guidelines from the American College of Physicians (ACP 2021) and the Infectious Diseases Society of America (IDSA 2015; 2014). 1 2 3 4 4 4 4 5 6 Definition Cellulitis is an acute bacterial infection of the deep dermis and subcutaneous tissue. 4 Epidemiology Cellulitis is primarily caused by -hemolytic Streptococci and S. aureus. 6 Pathophysiology The incidence of non-purulent lower extremity cellulitis is 176.6 per 100,000 persons in the United States. 5 Disease course After a breach in the skin causes the entry of pathogens into the dermis, the release of bacterial toxins and other inflammatory mediators results in dermal edema, lymphatic dilation, bulla formation https://web.pathway.md/diseases/recQx3nkGEjY3F6QL 1/5 6/29/23, 3:46 AM Cellulitis Pathway and regional lymphadenopathy. Untreated infection may progress to bacteremia and systemic inflammatory response syndrome. 4 Prognosis and risk of recurrence Approximately 17% of patients with acute cellulitis are unresponsive to initial treatment, and the risk of treatment failure is highest in obese patients. Recurrence of cellulitis occurs in approximately 14% and 45% cases within 1 year and 3 years, respectively. 4 4 Calculator ALT 70 score for cellulitis Guidelines 1. Diagnostic investigations Clinical examination: examine the interdigital toe spaces in patients with lower-extremity cellulitis. Treat fissuring, scaling, or maceration to eradicate colonization with pathogens and reduce the incidence of recurrent infection. B Blood and skin cultures: avoid routinely obtaining blood cultures or cultures of cutaneous aspirates, biopsies, or swabs in patients with cellulitis. D Show 2 more Evaluation for recurrent cellulitis: Identify and treat predisposing conditions such as edema, obesity, eczema, venous insufficiency, and toe web abnormalities. B Treat predisposing conditions both during the acute stage of cellulitis, and as part of routine patient care. B 2. Medical management Antibiotic therapy: As per Choosing Wisely 2015 guidelines, avoid antibiotic therapy for stasis dermatitis of lower extremities. Stasis dermatitis is commonly treated with antibiotic therapy, which may be a result of misdiagnosis or lack of awareness of the pathophysiology of the disease. D As per IDSA 2014 guidelines, administer an antimicrobial agent that is active against streptococci for patients with a typical presentation of cellulitis without systemic signs of infection. B Show 4 more https://web.pathway.md/diseases/recQx3nkGEjY3F6QL 2/5 6/29/23, 3:46 AM Cellulitis Pathway Setting of care: Provide outpatient therapy in patients who do not have systemic inflammatory response syndrome, altered mental status, or hemodynamic instability. B Hospitalize patients with a concern for a deeper or necrotizing infection, for patients with poor adherence to therapy, for infection in a severely immunocompromised patient, or if outpatient treatment is failing. B Duration of antibiotics: As per ACP 2021 guidelines, complete a 5- to 6-day course of antibiotics active against streptococci in patients with non-purulent cellulitis, particularly for patients able to self-monitor and who have close follow-up with primary care. B Complete at least 5 days of antimicrobial therapy, but extend the duration if the infection has not improved within this time period. A Adjunctive corticosteroids: consider systemic corticosteroids (e.g., prednisone 40 mg PO daily for 7 days) in adult patients with cellulitis who are not diabetic. C 3. Nonpharmacologic interventions Leg elevation: elevate the affected area and treat predisposing factors, such as edema or underlying cutaneous disorders. B 4. Preventative measures Antibiotic prophylaxis: consider administration of prophylactic antibiotics, such as oral penicillin or erythromycin BID for 4-52 weeks, or intramuscular benzathine penicillin every 2-4 weeks, in patients who have 3-4 episodes of cellulitis per year despite attempts to treat or control predisposing factors. C Landmark trials: PATCH-I In patients with 2 episodes of cellulitis of the leg, penicillin was superior to placebo with respect to first cellulitis recurrence, during the prophylaxis phase. Thomas KS et al. N Engl J Med. 2013 May 2. Clinical findings Symptoms Past medical history Fever Bacterial infection Pain Diabetes mellitus https://web.pathway.md/diseases/recQx3nkGEjY3F6QL 3/5 6/29/23, 3:46 AM Cellulitis Pathway Skin infection Human immunodeficiency virus infection Swelling Immunocompromising condition Social history Injury Leukemia Exposure to animal bite Obesity Lab findings Integument exam CRP Angioedema ESR Intraepidermal blistering Skin tenderness Hematological findings WBC count Studies 2020 CAMERA2 In hospitalized adults with MRSA bacteremia, combination therapy was not superior to standard therapy with respect to death, persistent bacteremia at day 5, microbiological relapse, or microbiological treatment failure at 90 days. Steven Y C Tong et al. JAMA. 2020 Feb 11. 2020 ICTOC In patients with chronic edema of the leg and recurrent cellulitis, compression was superior to control with respect to recurrence of cellulitis. Elizabeth Webb et al. N Engl J Med. 2020 Aug 13. Show 1 more References 1. Stevens DL, Bisno AL, Chambers HF et al. Practice guidelines for the diagnosis and management of skin and soft tissue infections: 2014 update by the Infectious Diseases Society of America. Clin Infect Dis. 2014 Jul 15;59 2):e10 52. Open 2. Rachael A Lee, Robert M Centor, Linda L Humphrey et al. Appropriate Use of Short-Course Antibiotics in Common Infections: Best Practice Advice From the American College of Physicians. Ann Intern Med. 2021 Apr 6. Open 3. Infectious Diseases Society of America. Choosing Wisely: Recommendations of the Infectious Diseases Society of America. Choosing Wisely. 2015 Feb. Open https://web.pathway.md/diseases/recQx3nkGEjY3F6QL 4/5 6/29/23, 3:46 AM Cellulitis Pathway 4. Adam B Raff, Daniela Kroshinsky. Cellulitis: A Review. JAMA. 2016 Jul 19;316 3 325 37. Open 5. Marcelin JR, Challener DW, Tan EM et al. Incidence and Effects of Seasonality on Nonpurulent Lower Extremity Cellulitis After the Emergence of Community-Acquired Methicillin-Resistant Staphylococcus aureus. Mayo Clin Proc. 2017 Aug;92 8 1227 1233. Open 6. Peterson RA, Polgreen LA, Cavanaugh JE et al. Increasing Incidence, Cost, and Seasonality in Patients Hospitalized for Cellulitis. Open Forum Infect Dis. 2017 Feb 8;4 1):ofx008. Open 7. S M Ellis Simonsen, E R van Orman, B E Hatch et al. Cellulitis incidence in a defined population. Epidemiol Infect. 2006 Apr;134 2 293 9. Open 8. Hae Suk Cheong, Yoosoo Chang, Eun-Jung Joo et al. Metabolic Obesity Phenotypes and Risk of Cellulitis: A Cohort Study. J Clin Med. 2019 Jun 30;8 7 953. Open 9. Galia Zacay, Fabienne Hershkowitz Sikron, Anthony D Heymann. Glycemic Control and Risk of Cellulitis. Diabetes Care. 2021 Feb;44 2 367 372. Open 10. Tadhg Sullivan, Eoghan de Barra. Diagnosis and management of cellulitis. Clin Med Lond). 2018 Mar;18 2 160 163. Open 11. C F Carey, L Dall. Diagnosis of cellulitis in the immunocompromised host. Can J Infect Dis. Winter 1990;1 4 133 5. Open 12. Jose R Rodriguez, Frank Hsieh, Ching-Tai Huang et al. Clinical features, microbiological epidemiology and recommendations for management of cellulitis in extremity lymphedema. J Surg Oncol. 2020 Jan;121 1 25 36. Open 13. Dennis L. Stevens, Amy E. Bryant Joseph J. Ferretti, Dennis L. Stevens et al. Impetigo, Erysipelas and Cellulitis. In: Streptococcus pyogenes: Basic Biology to Clinical Manifestations Internet]. Oklahoma City OK University of Oklahoma Health Sciences Center; 2016 . 2016 Feb 10. Open 14. Adam Dalal, Marina Eskin-Schwartz, Daniel Mimouni et al. Interventions for the prevention of recurrent erysipelas and cellulitis. Cochrane Database Syst Rev. 2017 Jun 20;6 6 CD009758. Open 15. Sean Singer, David G Li, Nicole Gunasekera et al. The ALT 70 cellulitis model maintains predictive value at 24 and 48 hours after presentation. J Am Acad Dermatol. 2019 Dec;81 6 1252 1256. Open 16. Sartelli M, Guirao X, Hardcastle TC et al. 2018 WSES/SIS E consensus conference: recommendations for the management of skin and soft-tissue infections. World J Emerg Surg. 2018 Dec 14;13 58. Open 17. Expert Panel on Musculoskeletal Imaging, Jennifer L Pierce, Michael T Perry et al. ACR Appropriateness Criteria Suspected Osteomyelitis, Septic Arthritis, or Soft Tissue Infection Excluding Spine and Diabetic Foot): 2022 Update. J Am Coll Radiol. 2022 Nov;19 11S S473 S487. Open https://web.pathway.md/diseases/recQx3nkGEjY3F6QL 5/5