What should be done if a cut or area of contact dermatitis shows signs of infection such as increasing erythema, warmth, swelling, purulent drainage, pain, fever, or lymphadenopathy?

Management of Infected Contact Dermatitis or Cuts

When a cut or area of contact dermatitis shows signs of infection—including increasing erythema, warmth, swelling, purulent drainage, pain, fever, or lymphadenopathy—the primary treatment is systemic antibiotics active against streptococci and staphylococci, not topical therapy alone. 1

Distinguishing Infection from Inflammation

The critical first step is determining whether you are dealing with true bacterial infection versus sterile inflammation:

• Purulent drainage (pus), crusting, weeping, or honey-colored crusts strongly suggest secondary bacterial infection, most commonly Staphylococcus aureus or Streptococcus pyogenes. 1
• Grouped, punched-out erosions or vesiculation indicate herpes simplex superinfection rather than bacterial infection, requiring different management. 1
• Systemic signs—fever, lymphadenopathy, or constitutional symptoms—mandate immediate systemic antibiotic therapy rather than observation or topical treatment alone. 1

A common pitfall: Labeling inflamed dermatitis with surrounding erythema as "cellulitis." The term cellulitis should be reserved for diffuse spreading infection without a purulent focus. When redness surrounds a suppurative area, the correct terminology is "infected dermatitis with surrounding inflammation," and the primary treatment shifts from antibiotics alone to drainage plus antibiotics. 1

Management Algorithm for Infected Contact Dermatitis

Step 1: Assess for Purulent Collections

• If fluctuance, localized abscess, or purulent material is present: incision and drainage is the primary treatment. Systemic antibiotics play only a subsidiary role. 1
• For simple cutaneous abscesses without extensive surrounding cellulitis or systemic features, drainage alone is usually sufficient—Gram stain, culture, and systemic antibiotics are rarely necessary. 1
• Exceptions requiring antibiotics after drainage include: multiple lesions, extensive surrounding cellulitis, severely impaired host defenses (neutropenia, severe immunodeficiency), or systemic manifestations like high fever. 1

Step 2: Initiate Systemic Antibiotics for Cellulitis or Systemic Infection

When true cellulitis (diffuse spreading erythema, warmth, tenderness without purulent collection) or systemic signs are present:

• First-line oral antibiotics should cover streptococci: penicillin, amoxicillin, amoxicillin-clavulanate, dicloxacillin, cephalexin, or clindamycin. 1
• A 5-day course is as effective as 10 days for uncomplicated cellulitis if clinical improvement occurs by day 5. 1
• MRSA coverage is usually unnecessary for typical cellulitis—a prospective study showed β-lactams (cefazolin, oxacillin) were successful in 96% of cellulitis cases, even in settings with high MRSA prevalence for other skin infections. 1
• Consider MRSA coverage only if: purulent drainage is present, the patient has failed β-lactam therapy, or there are severe systemic features (hypotension, delirium). 1

Step 3: Obtain Cultures Selectively

• Blood cultures and tissue cultures are unnecessary for typical cases of infected contact dermatitis or cellulitis. 1
• Obtain blood cultures and consider skin biopsy or aspirate cultures only when: malignancy is present, severe systemic features exist (high fever, hypotension), or unusual predisposing factors are present (immersion injury, animal bites, neutropenia, severe cell-mediated immunodeficiency). 1
• If herpes simplex is suspected (grouped erosions, vesiculation), send swabs for virological screening and electron microscopy. 1

Step 4: Topical Antimicrobials—Limited Role

• Topical mupirocin can be applied three times daily to small infected areas, with the option to cover with gauze dressing. Re-evaluate if no clinical response within 3–5 days. 2
• Combined topical corticosteroid/antibiotic preparations show only marginal benefit in infected or potentially infected eczema and should not replace systemic therapy when indicated. 3
• Avoid topical antibiotics like neomycin or bacitracin without clear indication—they are frequent contact allergens and may worsen dermatitis. 3

Step 5: Continue Barrier Restoration During Infection Treatment

• Do not discontinue emollients and moisturizers during antibiotic therapy—barrier restoration remains essential even when treating infection. 1, 3
• Topical corticosteroids can be continued cautiously on non-infected areas, but avoid applying potent steroids directly to purulent or crusted areas until infection is controlled. 1

Specific Clinical Scenarios

Impetigo (Superficial Bacterial Infection)

• Impetigo presents with honey-colored crusts, vesicles evolving to pustules, or bullae, typically on exposed areas (face, extremities). Regional lymphadenitis may occur, but systemic symptoms are usually absent. 1
• Streptococcal impetigo: organisms colonize skin 10 days before lesions appear, then transfer to the upper respiratory tract. 1
• Staphylococcal impetigo: nasal carriage precedes skin disease. 1

Furuncles (Boils)

• Furuncles are S. aureus infections of hair follicles extending into subcutaneous tissue, forming small abscesses. 1
• Small furuncles: moist heat to promote drainage is satisfactory. 1
• Larger furuncles and all carbuncles require incision and drainage. Systemic antibiotics are unnecessary unless extensive surrounding cellulitis or fever occurs. 1

Outbreak Control (Recurrent Furunculosis)

• For recurrent infections or outbreaks in close-contact settings (families, sports teams): consider bathing with antibacterial soaps (chlorhexidine), thorough laundering of clothing/towels/bedwear, separate use of personal items, and attempted eradication of nasal carriage with mupirocin. 1
• Dilute bleach baths (¼–½ cup per full bath) may prevent recurrences, though data on efficacy are sparse. 1
• Treating both the patient and household contacts results in significantly fewer recurrences than treating the patient alone. 1

Critical Pitfalls to Avoid

• Do not treat purulent collections with antibiotics alone—drainage is the primary therapy. 1
• Do not label inflamed dermatitis with surrounding redness as "cellulitis with abscess"—this terminology error leads to inappropriate antibiotic-only management when drainage is needed. 1
• Do not assume worsening inflammation after starting antibiotics means treatment failure—sudden destruction of pathogens can release enzymes that temporarily increase local inflammation. 1
• Do not routinely cover MRSA in typical cellulitis—this leads to unnecessary broad-spectrum therapy with higher failure rates (12%) and no benefit over targeted β-lactam therapy. 1
• Do not use disinfectant wipes on infected skin—they contain harsh antimicrobials (e.g., N-alkyl dimethyl benzyl ammonium chloride) that worsen dermatitis. 3

When to Escalate Care

• Refer immediately if: fever with hypotension, delirium, rapidly spreading erythema, cutaneous gangrene, or signs of necrotizing infection develop. 1
• Consider dermatology consultation if: infection recurs despite appropriate treatment, herpes simplex superinfection is suspected, or the underlying dermatitis remains refractory. 1, 3