- Poststreptococcal glomerulonephritis is caused by nephritogenic strains of streptococci which can cause skin infections and pharyngitis. It presents a couple of weeks after the primary infection.
- Staphylococcal scalded skin syndrome (SSSS) is characterized by an erythematous rash followed by diffuse epidermal exfoliation. Patients are managed similarly to a burn patient. The mortality rate is low unless associated with sepsis.
- Methicillin-resistant Staphylococcus aureus (MRSA) is responsible for many serious skin and soft tissue infections as well as bacterial pneumonia.
- Tinea corporis can be treated effectively with topical antifungals, but tinea capitis requires systemic antifungal therapy.
Staphylococcus aureus and group A β-hemolytic Streptococcus are the organisms that are most commonly isolated from skin infections. MRSA can be isolated from 70% to 80% of impetigo in certain areas of the United States.1
Pathogens colonize the skin surface and occasionally invade the damaged epidermal layer and replicate within the skin. Breaks in the skin can be caused by trauma and from scratching atopic skin. Transmission occurs through direct contact; therefore, new lesions may be seen on the patient with no apparent break in the skin. The depth of invasion provides a clinical continuum for impetigo and ecthyma.
Impetigo refers to a superficial bacterial infection of the epithelium. It usually occurs in younger children who may be exposed to poor skin hygiene. They initially present as small vesicles and pustules that eventually rupture. The lesions become eroded and progress to areas of honey-crusted lesions. Exposed areas such as the face and extremities are more commonly affected (Fig. 87–1A).
(A) Classic “honey-crusted” lesions of impetigo. (B) Chronic impetigo. (C) Neonatal pyoderma.
Ecthyma describes the bacterial infections that affect the deeper layers of the epidermis. They are characterized by firm, dark crust that usually contains purulent exudate. The surrounding area is erythematous and indurated (Fig. 87–1B). Neonatal pyoderma is usually a result of a superficial staphylococcal infection and is manifested by variable-sized pustules and bullae (Fig. 87–1C).
Topical mupirocin ointment can be used for uncomplicated, localized lesions. Areas with larger involvement require oral antibiotics. When systemic antibiotics are needed, the choice of antibiotics should be determined by local resistance patterns. A 10-day course of penicillin or cephalosporins may be sufficient coverage for gram-positive organisms in some areas.1 Erythromycin is used for penicillin- or cephalosporin-allergic patients, but has little coverage for MRSA. Clindamycin has maintained its sensitivity for MRSA in some areas, and therefore, is a good choice when resistance is recognized. Good hand washing ...