Bacterial Skin Infections: Types, Treatment, and Nursing Care

Skin infections range from superficial conditions like impetigo to deep, life-threatening processes like necrotizing fasciitis. Correctly identifying the type of infection guides antibiotic choice, isolation precautions, and recognition of complications such as sepsis or tissue necrosis.

Overview of Common Bacterial Skin Infections

Cellulitis

• Deep dermis and subcutaneous tissue infection with diffuse, poorly defined borders.
• Most common organisms: Streptococcus pyogenes (Group A Strep) and Staphylococcus aureus.
• Skin is red, warm, swollen, and tender; fever may be present.
• First-line (non-purulent): cephalexin or dicloxacillin.
• Severe / hospitalized: IV cefazolin or vancomycin.

Erysipelas

• Superficial dermal and lymphatic infection caused almost exclusively by Group A Streptococcus.
• Raised, sharply demarcated, bright red border with a shiny or "peau d'orange" appearance.
• Fever and systemic symptoms are more common than in cellulitis.
• First-line: penicillin or amoxicillin. For penicillin allergy: macrolides or clindamycin.

Impetigo

• Superficial epidermal infection that is highly contagious, most common in young children.
• Caused by S. aureus, S. pyogenes, or both; presents with honey-colored crusted lesions.
• Spreads via direct contact or scratching; autoinoculation can spread lesions.
• Mild: topical mupirocin. Widespread: oral cephalexin or amoxicillin-clavulanate.
• Children may return to school 24 hours after starting effective antibiotics and when lesions are no longer weeping.

Folliculitis, Furuncle, and Carbuncle

• Folliculitis: superficial infection of the hair follicle; small pustules around follicles.
• Furuncle (boil): infection extending into subcutaneous tissue; painful, fluctuant nodule.
• Carbuncle: cluster of interconnected furuncles with multiple draining sinus tracts; often systemic symptoms.
• Most common organism for all three: S. aureus, including MRSA.
• Warm compresses promote drainage; incision and drainage may be needed for larger lesions.
• Hot tub folliculitis is caused by Pseudomonas and typically resolves without antibiotics.

Cutaneous Abscess

• Localized collection of pus in the dermis or subcutaneous tissue.
• Presents as a fluctuant, tender, swollen mass, often with surrounding cellulitis.
• Most common organism: S. aureus.
• Definitive treatment is incision and drainage (I&D) — antibiotics alone are not sufficient.

Necrotizing Fasciitis (Emergency)

• Rapidly progressive infection of fascia and deep soft tissue; surgical emergency with high mortality.
• Hallmark sign: pain out of proportion to visible physical findings.
• Early skin changes may be minimal; late findings include bullae, skin discoloration, and necrosis.
• First nursing action: notify the provider immediately and prepare for emergency debridement.
• Treatment: urgent surgical debridement plus IV broad-spectrum antibiotics (e.g., vancomycin + piperacillin-tazobactam).

MRSA Skin Infections

• Methicillin-resistant Staphylococcus aureus commonly causes abscesses, furuncles, and cellulitis.
• Transmitted by direct contact or contaminated surfaces — requires contact precautions.
• Mild to moderate: TMP-SMX (Bactrim), doxycycline, or clindamycin.
• Severe, hospitalized, or immunocompromised: vancomycin.
• For recurrent MRSA, consider decolonization with chlorhexidine body washes and nasal mupirocin.

Infection Control Precautions

Nursing Management

• Choose antibiotics based on organism, severity, and MRSA risk; obtain wound cultures before starting antibiotics when possible.
• Use warm compresses to promote drainage in localized infections.
• Perform I&D for abscesses — antibiotics alone are insufficient.
• Monitor for signs of sepsis: fever, tachycardia, hypotension, altered mental status.
• For necrotizing fasciitis, prepare for emergency surgical debridement and notify the OR immediately.

Patient Education

• Complete the full course of antibiotics even if symptoms improve.
• Practice hand hygiene; avoid sharing towels, razors, and other personal items.
• Keep wounds clean, dry, and covered; avoid scratching to prevent spread.
• Report worsening redness, swelling, fever, or pain promptly.
• For recurrent MRSA, use chlorhexidine washes and nasal mupirocin for decolonization.

Common Exam Traps

• Cellulitis = diffuse borders; erysipelas = sharply demarcated, raised borders.
• Impetigo = honey-colored crusts, not acne-like pustules.
• Abscesses require I&D, not antibiotics alone.
• Necrotizing fasciitis: pain out of proportion — first action is notify provider and prepare for surgery.
• MRSA requires contact precautions, not standard precautions alone.
• Hot tub folliculitis: Pseudomonas; usually resolves without antibiotics.
• Impetigo: return to school 24 hours after starting antibiotics and once lesions are crusted/dry.

Key Takeaways

• Skin infections span a spectrum: superficial (impetigo) → deep (cellulitis) → life-threatening (necrotizing fasciitis).
• Cellulitis has diffuse borders; erysipelas has sharply demarcated, raised, bright red borders.
• Abscesses require incision and drainage — antibiotics alone won't cure them.
• MRSA requires contact precautions and specific antibiotics: TMP-SMX, doxycycline, or clindamycin (vancomycin if severe).
• Necrotizing fasciitis is a surgical emergency — recognize pain out of proportion and act fast.
• Nursing priorities: early recognition, infection control, appropriate antibiotics, I&D when indicated, and sepsis monitoring.