What is the best treatment approach for a patient with infected contact dermatitis on their back?

Treatment of Infected Contact Dermatitis on the Back

For infected contact dermatitis on the back, treat with topical mupirocin three times daily for the infection combined with a high-potency topical corticosteroid (such as clobetasol propionate 0.05%) for up to 2 weeks, while aggressively moisturizing and identifying/avoiding the causative allergen or irritant. 1, 2, 3

Immediate Management of Infection

Bacterial infection is indicated by crusting or weeping and requires antimicrobial therapy before inflammation can be adequately controlled. 4

• Apply mupirocin ointment to the affected area three times daily, which may be covered with gauze dressing if desired 2
• Re-evaluate patients not showing clinical response within 3 to 5 days 2
• Combined topical corticosteroid/antibiotic preparations show marginal benefit and should generally be avoided in favor of separate agents 1

Concurrent Anti-Inflammatory Treatment

High-potency topical corticosteroids are essential for controlling the underlying dermatitis while treating infection. 1, 5, 3

• Apply clobetasol propionate 0.05% to affected areas for up to 2 weeks, which achieves clear or almost clear skin in 67.2% of patients with severe dermatitis 1, 5
• The back tolerates potent steroids well due to thicker skin, but limit duration to 2 weeks to prevent systemic absorption 1
• Apply topical corticosteroids separately from mupirocin, spacing applications throughout the day 4

Aggressive Moisturization Protocol

Emollients are foundational to restoring skin barrier function and preventing recurrence. 4, 1

• Use tube-packaged moisturizers rather than jars to prevent contamination 1, 5
• Apply moisturizers immediately after bathing to damp skin to maximize hydration 4
• Consider the "soak and smear" technique: soak affected area for 20 minutes in plain water, then immediately apply moisturizer nightly 5
• Patients should use approximately 100g of moisturizer per 2 weeks for trunk area 1

Allergen and Irritant Identification

Complete avoidance of the causative agent is essential to prevent recurrence, making identification critical. 1, 3

• Obtain detailed history of initial symptom location, spread pattern, and relationship to specific products or activities 1
• Common back exposures include: fabric softeners, laundry detergents, fragrances in body washes, clothing materials (especially wool), and metals in bra clasps or belt buckles 4, 1
• Replace all soaps and body washes with fragrance-free soap substitutes immediately, as these are universal irritants that perpetuate inflammation 1
• Switch to fragrance-free, dye-free laundry detergents and avoid fabric softeners entirely 5

When to Refer for Patch Testing

Refer for patch testing if dermatitis persists beyond 4 weeks or recurs despite treatment, as clinical features alone cannot distinguish allergic from irritant contact dermatitis. 1, 5, 3

• Patch testing should include at least an extended standard series of allergens 1
• Critical pitfall: Do not apply potent topical steroids to the back within 2 days of patch testing, as this causes false negatives 1
• Avoid oral corticosteroids or immunosuppressants during patch testing; if unavoidable, keep prednisolone ≤10 mg daily 1

Escalation for Refractory Cases

If infection clears but dermatitis persists after 2 weeks of high-potency steroids and allergen avoidance, consider second-line therapies. 1, 5

• Topical tacrolimus 0.1% is an effective steroid-sparing alternative that avoids atrophy risk 1, 5
• PUVA phototherapy is established second-line treatment for chronic contact dermatitis resistant to topical steroids 1
• For severe refractory cases, consider systemic immunosuppressants: azathioprine, ciclosporin, methotrexate, or mycophenolate mofetil 1

Common Pitfalls to Avoid

• Never apply products containing topical antibiotics (especially neomycin) without clear indication, as these are common contact allergens causing reactions in 5-15% of patients with chronic dermatitis 4, 5
• Do not use disinfectant wipes or harsh soaps on affected skin 5
• Avoid washing with very hot or very cold water 5
• Do not over-rely on barrier creams alone, as they have questionable value and may create false security 1

Prognosis and Follow-Up

The prognosis for persistent contact dermatitis is guarded: only 25% achieve complete healing, 50% have intermittent symptoms, and 25% have permanent symptoms despite treatment. 1, 5

• Early identification and complete avoidance of causative allergens offers the best chance for resolution 1, 5
• Re-evaluate within 3-5 days to ensure infection is responding to mupirocin 2
• If no improvement after 2 weeks of combined therapy, refer to dermatology for patch testing and consideration of second-line therapies 1, 3