A guide to the Tx of cellulitis and other soft-tissue infections

Antibiotic therapy, generally administered intravenously, is recommended for at least 3 days or until orbital symptoms begin to resolve. Choose antibiotics effective against sinusitis-related pathogens (eg, S pneumoniae, H influenzae, M catarrhalis), S aureus, and anaerobes.⁸ For instance, a regimen may include vancomycin for MRSA coverage, a third-generation cephalosporin, or metronidazole for anaerobic coverage if there is concern about intracranial involvement. Surgical intervention is often reserved for patients with inadequate response to antibiotic therapy, necessitating biopsy for pathogen identification, as well as drainage of large abscesses refractory to antibiotics.

Erysipelas

Erysipelas, a related yet distinct form of cellulitis, is a bacterial infection of the superficial dermis and hypodermis and is commonly caused by group A streptococcus.^5,9 Other less common organisms include S aureus, P aeruginosa, and enterobacteria. Erysipelas predominantly affects the lower extremities unilaterally (~90%); the arms and the face are the next most common locations. In addition to the rapid onset of well-demarcated erythema, pain, and swelling, patients may have fever and regional lymphadenopathy. Risk factors include portal of entry (eg, tinea pedis, ulceration), lymphedema, and diabetes. Complications of erysipelas include bullae from edema, abscess formation, and, rarely, bacteremia.

When clinical exam alone is inconclusive when evaluating skin and softtissue infections in children and adolescents, consider using ultrasound to improve diagnostic accuracy.

Antibiotic treatment regimens include penicillin G, macrolides (reserved for those with penicillin allergies), fluoroquinolones, and cephalosporins, with duration of treatment ranging from 10 to 14 days depending on infection severity. Fever, pain, and erythema generally improve within 48 to 72 hours of antibiotic therapy. If there is no improvement, consider alternative diagnoses, such as necrotizing fasciitis. Recurrence rates following the initial episode of erysipelas are estimated at 10% of patients at 6 months and 30% at 3 years.¹⁰

Folliculitis

Inflammation of hair follicles is characterized by superficial inflammation with the development of perifollicular papules or pustules on an erythematous base.^11,12 Folliculitis most commonly affects the face, scalp, thighs, buttocks, axillae, and inguinal areas.¹³ It may be caused by infection, an inflammatory reaction, or physical injury. Diagnosis is typically based on the patient’s history and physical examination.

Bacteria are the most common cause of infection, although fungi, viruses, and other entities can cause folliculitis. S aureus (methicillin sensitive or methicillin resistant) is the most common pathogen; in the past, superficial pustular folliculitis attributed to S aureus was referred to as Bockhart impetigo. Folliculitis secondary to P aeruginosa, often seen after exposure to contaminated water or hot tubs, is frequently referred to as “hot tub folliculitis.” Malassezia, a reported cause of fungal folliculitis, tends to occur in adolescents of either sex and men with high sebum production, is common in tropical climates, and can be associated with HIV or immunosuppression.^11,12,14

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