Cellulitis and erysipelas

Overview 
Theory 
Diagnosis 
Management 
Follow up 
Resources 

The goal of therapy for cellulitis and erysipelas is resolution of the clinical signs and symptoms and eradication of organisms. This is usually accomplished through the use of systemic antimicrobial therapy. [ ] The clinician's assessment of the severity of illness should dictate the route of administration and the setting for treatment. Factors to consider include systemic signs or symptoms, comorbid medical conditions, and ability to tolerate oral medications.

Before starting treatment for cellulitis or erysipelas, consider drawing around the extent of the infection with a single-use surgical marker pen to monitor progress, but note that redness may be less apparent or appear more violaceous on darker skin tones.[20]

Antibiotic therapy

All patients with cellulitis or erysipelas should be treated with antibiotics. There is little high-quality evidence available to indicate the most appropriate empiric antibiotic, route of administration, or duration.[81][82] One network meta-analysis (search date July 2024) looking at multiple antibiotics found no significant differences in cure rates among antibiotics for cellulitis.[83]

As with all infections, local antibiotic protocols should be consulted to determine the most appropriate choice, based on local pathogen prevalence and antibiotic resistance patterns, and with the goal of narrow-spectrum antibiotics, oral route, and dose optimization when possible.[84][85]

Recommendations from the Infectious Diseases Society of America (IDSA) are as follows:[13]

Mild cellulitis/erysipelas (without purulence or systemic signs of infection): therapy should include an oral antibiotic active against streptococci. Suitable antibiotics for most patients include penicillin V, a cephalosporin, dicloxacillin, or clindamycin. The treatment of erysipelas should follow the same principles as that for cellulitis.
Moderate cellulitis/erysipelas (with systemic signs of infection): intravenous antibiotics such as penicillin G, ceftriaxone, cefazolin, or clindamycin should be used. Signs of systemic infection include temperature >100.4°F (38°C), tachycardia (heart rate >90 beats per minute), tachypnea (respiratory rate >24 breaths per minute) or abnormal white blood cell count (>12,000 or <400 cells/microliter).
Severe cellulitis/erysipelas (failed oral antibiotic treatment or with systemic signs of infection [as defined above], immunocompromised, or with clinical signs of deeper infection such as bullae, skin sloughing, hypotension, or evidence of organ dysfunction): in these patients, vancomycin or another antibiotic effective against both MRSA and streptococci is recommended. Vancomycin plus either piperacillin/tazobactam or imipenem/cilastatin is recommended as a reasonable empiric regimen for severe infections. In severely immunocompromised patients (malignancy on chemotherapy, neutropenia, severe cell-mediated immunodeficiency), broad-spectrum antimicrobial coverage may be considered.
In severe penicillin allergy in which there is type-I immediate hypersensitivity reaction, a non-beta-lactam antibiotic is indicated.

Specific circumstances

Coverage for MRSA may be prudent in cellulitis associated with penetrating trauma, especially from illicit drug use, purulent drainage, or with concurrent evidence of MRSA infection elsewhere. Options for treatment of MRSA in these circumstances include intravenous vancomycin, linezolid, or daptomycin.[13]
Cellulitis restricted to certain anatomic zones (e.g., perianal, facial) may suggest specific organisms requiring targeted antimicrobial therapy.[86]
Cellulitis in the setting of altered host immunity, diabetic foot ulcers, bite wounds, or exposure to salt or fresh water may be due to less traditional organisms, and therapy should be modified accordingly.[13] See our topics "Animal bites" and "Diabetic foot infections".

Route of administration

A large percentage of patients can receive oral medications from the start for typical cellulitis with no focus of purulence.[86]
For cellulitis with systemic signs of infection, intravenous antibiotics are indicated.[13] Intravenous antibiotics may be given in the outpatient setting if the facilities and expertise are available.
Intravenous antibiotics should be switched to oral once the patient is clinically stable (i.e., systemically well and comorbidities are stable).[87]

Duration of treatment

The recommended duration of antibiotic therapy depends on the severity and site of infection.
IDSA and the World Society of Emergency Surgery (WSES) recommend antibiotic therapy for 5-7 days in uncomplicated cellulitis, and advises that treatment should be extended if the infection is severe, or if it has not improved within this time period.[2][13]
WSES and the Surgical Infection Society Europe (SIS-E) recommend 7-14 days of antibiotic therapy for MRSA skin and soft-tissue infections (individualized based on the patient’s clinical response).[87]
The American College of Physicians recommends that patients with nonpurulent cellulitis should receive antibiotics for 5-6 days.[88]

Surgical inspection and debridement

In severe infection, urgent surgical inspection and debridement is indicated to rule out a necrotizing process.[13] See our topic "Necrotizing fasciitis" for more information.

Supportive management

Sepsis should be suspected if there is acute deterioration in a patient in whom there is clinical evidence or strong suspicion of infection. Senior colleagues should be involved as indicated, and local sepsis protocols followed. See Sepsis in adults.

Supportive management includes the use of adequate pain relief, elevation of the affected area, and treatment of predisposing factors (such as edema or underlying cutaneous disorders).[13]

Adequate analgesia should be prescribed. Acetaminophen or a nonsteroidal anti-inflammatory drug (NSAID; e.g., ibuprofen) are usually appropriate. One meta-analysis found in patients with cellulitis, oral NSAIDs as adjunct therapy to antibiotics may lead to improved early clinical response, although this was shown only up to the first four days.[89]

Any blisters should be proactively aspirated and/or deroofed using aseptic technique.[41] Aspirates should be sent for microbiological processing. Wound exudates should be managed if the skin ulcerates. Absorbent but nonadhesive dressings can be used according to local wound management protocols.

Thromboprophylaxis should be considered based on risk stratification, as for all patients admitted to hospital. Local protocols should be consulted.

Failure to improve with standard therapy

Features that suggest treatment failure include persistence or worsening of clinical findings such as fever or pain, or extension of erythema in the involved area.

This should prompt consideration of infection with resistant strains of organisms, extension to deeper tissues (e.g., necrotizing fasciitis), abscess formation, or an alternative diagnosis, such as an inflammatory reaction to an immunization or insect bite, stasis dermatitis, gout, superficial thrombophlebitis, eczema, allergic dermatitis, or deep vein thrombosis.[70] It should be noted that cellulitis in the setting of chronic lymphedema or venous insufficiency is often slow to resolve.[27]

Considering the common etiologies of cellulitis, modifying antimicrobial therapy to provide activity for MRSA is a suggested initial step in management of a poorly responsive cellulitis.

Recurrent disease

Patients with a previous episode of cellulitis have annual recurrence rates of about 8% to 20%, with the risk being higher if the legs are involved.[13] Those who experience recurrent episodes of cellulitis may benefit from efforts to keep skin hydrated, control of chronic dermatoses (e.g., tinea pedis interdigitalis), or, in some cases, antibiotic prophylaxis.[14] [ ] [Evidence B] Predisposing conditions such as edema, obesity, eczema, venous insufficiency, and toe web abnormalities should be identified and treated.[2][13]

Recurrent disease is common especially in those with persistent risk factors (e.g., lymphedema, venous insufficiency, tinea pedis).[2][14][23] Usually beta-hemolytic streptococci are the cause. Prophylactic antibiotics such as oral penicillin or erythromycin should be considered in patients who have 3 to 4 episodes of cellulitis per year despite attempts to treat or control predisposing factors. This program should be continued so long as the predisposing factors persist.[13] Local antibiotic protocols should be consulted to determine the most appropriate choice of antibiotic based on local pathogen prevalence and antibiotic resistance patterns.

Surgical intervention to correct lymphedema may be an option in some patients with recurrent disease.[90]

Chronic cellulitis is rare, usually occurs only in immunocompromised patients, and is restricted to indolent organisms. An alternative diagnosis to cellulitis is more likely. In some cases, such as in patients with chronic lymphedema, the appearance of the skin can remain abnormal for an extended period but the persistence of organisms requiring antimicrobial therapy is unlikely.

In patients with chronic edema and cellulitis, compression therapy may help reduce recurrence.[91]

Peripheral intravascular catheter: animated demonstration

How to insert a peripheral intravascular catheter into the dorsum of the hand.

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