What is the diagnosis and treatment for cellulitis?

From the Guidelines

Cellulitis should be treated with an antimicrobial agent active against streptococci, and the recommended duration of antimicrobial therapy is 5 days, but treatment should be extended if the infection has not improved within this time period. The diagnosis of cellulitis is typically based on clinical presentation, and cultures of blood or cutaneous aspirates, biopsies, or swabs are not routinely recommended 1. However, cultures of blood are recommended, and cultures and microscopic examination of cutaneous aspirates, biopsies, or swabs should be considered in patients with certain underlying conditions, such as malignancy on chemotherapy, neutropenia, or severe cell-mediated immunodeficiency 1.

For typical cases of cellulitis without systemic signs of infection, oral antibiotics like cephalexin, dicloxacillin, or amoxicillin-clavulanate are suitable options 1. In cases of uncomplicated cellulitis, a 5-day course of antimicrobial therapy is as effective as a 10-day course, if clinical improvement has occurred by 5 days 1. It's also important to note that patients with cellulitis should elevate the affected area, rest, and apply warm compresses to improve circulation and reduce swelling.

Some key points to consider in the treatment of cellulitis include:

• The use of broad-spectrum antimicrobial coverage may be considered in severely compromised patients 1
• Vancomycin or another antimicrobial effective against both MRSA and streptococci is recommended for patients with certain risk factors, such as penetrating trauma or evidence of MRSA infection elsewhere 1
• Outpatient therapy is recommended for patients who do not have systemic signs of infection, altered mental status, or hemodynamic instability 1
• Hospitalization is recommended if there is concern for a deeper or necrotizing infection, or for patients with poor adherence to therapy or severe immunocompromisation 1.

Overall, the treatment of cellulitis should be tailored to the individual patient's needs and underlying risk factors, and should prioritize the use of antimicrobial agents active against streptococci, with consideration of broader coverage in certain cases.

From the FDA Drug Label

Patients with cellulitis/erysipelas, major cutaneous abscess, or wound infection were enrolled in the trials The types of ABSSSI included were cellulitis/erysipelas (41%), wound infection (29%), and major cutaneous abscess (30%) The primary endpoint in Trial 1 was early clinical response defined as no increase from baseline lesion area at 48-72 hours after the first dose and oral temperature of ≤37. 6°C, confirmed by a second temperature measurement within 24 hours in the ITT population. Clinical success was defined as resolution or near resolution of most disease-specific signs and symptoms, absence or near resolution of systemic signs of infection if present at baseline (lymphadenopathy, fever, >10% immature neutrophils, abnormal WBC count), and no new signs, symptoms, or complications attributable to the ABSSSI requiring further treatment of the primary lesion

The diagnosis of cellulitis is based on clinical presentation, including local signs and symptoms of infection, such as lesion area, and at least one regional or systemic sign of infection, including:

• Lymphadenopathy
• Temperature 38°C or higher
• White blood cell count greater than 10,000 cells/mm3 or less than 4000 cells/mm3
• 10% or more band forms on white blood cell differential The treatment for cellulitis includes antibiotics, such as tedizolid, with a treatment duration of 6 days 2.

From the Research

Diagnosis of Cellulitis

• Cellulitis is typically diagnosed based on clinical presentation, including signs and symptoms such as redness, swelling, warmth, and tenderness of the affected area 3, 4, 5, 6, 7.
• Laboratory tests, such as blood cultures and complete blood counts, may be ordered to rule out other conditions and to assess the severity of the infection 3, 4, 6.
• Imaging studies, such as ultrasound or MRI, may be used to evaluate the extent of the infection and to rule out other conditions, such as abscesses or deep vein thrombosis 6.

Treatment of Cellulitis

• Antibiotic therapy is the primary treatment for cellulitis, with the choice of antibiotic depending on the suspected causative organism and the severity of the infection 3, 4, 5, 6, 7.
• For uncomplicated cellulitis, oral antibiotics such as cephalexin, trimethoprim-sulfamethoxazole, or clindamycin may be prescribed 3, 4, 7.
• For more severe cases of cellulitis, intravenous antibiotics may be necessary, and hospitalization may be required 6.
• Anti-inflammatory medications, such as ibuprofen, may be prescribed to reduce pain and inflammation 5.
• The duration of antibiotic therapy typically ranges from 5 to 14 days, depending on the severity of the infection and the response to treatment 4, 6, 7.

Factors Affecting Treatment Outcome

• The presence of methicillin-resistant Staphylococcus aureus (MRSA) may affect treatment outcome, with antibiotics that are active against MRSA being preferred in areas with high prevalence of MRSA infections 3, 4.
• The severity of the infection, including the size of the affected area and the presence of systemic symptoms, may also affect treatment outcome 3, 6.
• Patient factors, such as age, comorbidities, and immune status, may also influence treatment outcome 6.