From the Guidelines
Cellulitis is primarily caused by bacterial infections, most commonly Streptococcus and Staphylococcus species, which enter the skin through breaks or cracks, and the most recent guidelines recommend treating typical cases with an antimicrobial agent active against streptococci 1. The bacteria responsible for cellulitis typically penetrate the skin through cuts, scrapes, burns, insect bites, surgical wounds, or skin conditions like eczema or athlete's foot. Some key factors that increase susceptibility to cellulitis include:
- Having a weakened immune system
- Diabetes
- Peripheral vascular disease
- Lymphedema
- Obesity
- Poor circulation, which can reduce the body's ability to fight infection in affected areas
- Certain skin conditions that compromise the skin barrier function, making infection more likely The bacteria multiply rapidly in the deeper layers of skin, causing inflammation, redness, swelling, warmth, and pain in the affected area. Without proper treatment, usually with antibiotics like cephalexin, dicloxacillin, or clindamycin for 5-14 days depending on severity, the infection can spread to the bloodstream and lymph nodes, potentially becoming life-threatening 1. Maintaining good skin hygiene, promptly cleaning wounds, and managing underlying conditions can help prevent cellulitis. It is also recommended to elevate the affected area and treat predisposing factors, such as edema or underlying cutaneous disorders, to promote recovery 1. In cases of recurrent cellulitis, measures to reduce recurrences include treating interdigital maceration, keeping the skin well hydrated with emollients, and reducing any underlying edema, and prophylactic antibiotics may be considered in some cases 1.
From the Research
Causes of Cellulitis
The causes of cellulitis are primarily infectious, with the majority of non-purulent, uncomplicated cases being caused by:
- β-hemolytic streptococci
- Methicillin-sensitive Staphylococcus aureus 2 However, it's worth noting that microbiological diagnosis is often unobtainable due to poor sensitivity of culture specimens 2.
Pathogenesis and Diagnosis
Cellulitis is a clinical diagnosis based on the history of present illness and physical examination, and lacks a gold standard for diagnosis 2, 3. The clinical presentation typically includes:
- Acute onset of redness
- Warmth
- Swelling
- Tenderness
- Pain 2, 3 A thorough history and clinical examination can help narrow the differential diagnosis of cellulitis and minimize unnecessary hospitalization 3.
Microbial Culprits
The most likely microbial culprit is often determined by patient history and risk factors, severity of clinical presentation 3. However, there is no evidence to support the superiority of any one antibiotic over another, and antibiotics with activity against methicillin-resistant Staphylococcus aureus did not add an advantage 4.