Bacterial Skin Infections (Impetigo, Folliculitis & Cellulitis)

Common Bacterial Skin Infections

Impetigo

Superficial, highly contagious infection causing honey-colored crusted sores, most commonly around the nose and mouth in children. Caused by *S. aureus* or *S. pyogenes*. Treated with topical mupirocin or retapamulin; oral antibiotics for extensive disease.

Folliculitis

Infection of hair follicles presenting as red papules or pustules. Bacterial (S. aureus), gram-negative (hot tub folliculitis from *Pseudomonas aeruginosa*), or fungal (Pityrosporum). Mild cases: topical antibiotics or antiseptic washes. Recurrent: oral antibiotics, decolonization protocol.

Cellulitis

Diffuse, spreading infection of the deep dermis and subcutaneous tissue — red, warm, swollen, tender skin with poorly defined borders, often on the lower leg. Usually *S. aureus* or streptococcal. Oral antibiotics (cephalexin, dicloxacillin, or TMP-SMX for MRSA coverage) for most cases; IV for high-grade fever, rapid spread, or immunocompromise.

Erysipelas

Superficial variant of cellulitis with sharply demarcated, raised borders — typically streptococcal and responds well to penicillin/amoxicillin.

Abscesses (Furuncles, Carbuncles)

Localized collections of pus. First-line: incision and drainage. Antibiotics added for surrounding cellulitis, systemic symptoms, or MRSA risk factors.

MRSA

Community-acquired MRSA is increasingly common in South Florida. Suspicious features: abscesses that recur, fail drainage alone, or occur in clusters within households. Culture before treating and use TMP-SMX, doxycycline, or clindamycin as appropriate.