Cellulitis and erysipelas manifest as areas of skin erythema, edema, and warmth in the absence of underlying suppurative foci. Erysipelas has more distinctive anatomic features than cellulitis; erysipelas lesions are raised above the level of surrounding skin so that a clear line of demarcation between involved and uninvolved tissue is usually present.
Predisposing factors include disruption to the skin barrier as a result of trauma (such as penetrating wounds or injection drug use), inflammation (such as eczema or radiation therapy), preexisting skin infection (such as impetigo or tinea pedis), and edema (due to venous insufficiency).
The diagnosis of cellulitis is based upon clinical manifestations. Cultures are necessary only in patients with systemic toxicity, extensive skin involvement, underlying comorbidities, special exposures (animal bite, water-associated injury), or recurrent or persistent cellulitis.
The most common causes of cellulitis are beta-hemolytic Streptococcus (groups A, B, C, G, and F), and other pathogens include Staphylococcus aureus; gram-negative aerobic bacilli are identified in a minority of cases. Beta-hemolytic streptococci are the predominant cause of erysipelas.
Management of cellulitis and erysipelas should include supportive measures, such as elevation of the affected area and treatment of underlying predisposing conditions.
Patients with mild cellulitis may be treated with oral antibiotics．We recommend that patients with signs of systemic toxicity or erythema that has progressed rapidly should be treated initially with parenteral antibiotics (Grade 1B). Parenteral therapy is also appropriate for patients with persistence or progression of symptoms despite 48 to 72 hours of appropriate oral therapy.
Patients with nonpurulent cellulitis should be managed with empiric therapy for infection due to beta-hemolytic streptococci and methicillin-susceptible S. aureus (MSSA). Patients with nonpurulent cellulitis and additional risk factors for methicillin-resistant S. aureus (MRSA) should be managed with empiric therapy for infection due to beta-hemolytic streptococci and MRSA.
Patients with purulent cellulitis (eg, cellulitis associated with purulent drainage or exudate, in the absence of a drainable abscess) should be managed with empiric therapy for infection due to MRSA, pending culture results．
Treatment of cellulitis for neonates usually requires initial parenteral therapy．Therapy is usually administered for 7 to 10 days.
Patients with erysipelas and systemic manifestations (such as fever and chills) should be treated with parenteral therapy. Patients with mild infection or those who have improved following initial treatment with parenteral antibiotic therapy may be treated with oral therapy．
The duration of therapy should be individualized depending on clinical response.
We suggest administration of suppressive antibiotic therapy for patients with recurrent cellulitis who have predisposing factors that cannot be alleviated (Grade 2B).