What is the treatment for cutaneous drug eruption and allergic contact dermatitis?

Treatment of Cutaneous Drug Eruption and Allergic Contact Dermatitis

Immediately discontinue the suspected causative drug or allergen, apply mid-to-high potency topical corticosteroids for localized disease, and escalate to systemic corticosteroids for extensive involvement (>20% body surface area). 1, 2

Immediate Management: Stop the Offending Agent

• Complete avoidance of the causative substance is the absolute cornerstone of treatment—without this, no amount of topical therapy will achieve resolution. 1, 3
• For cutaneous drug eruptions, discontinue all suspected medications immediately and document the reaction for future avoidance. 4
• For allergic contact dermatitis, identify and eliminate exposure to allergens (cosmetics, fragrances, metals, topical medications) and irritants (detergents, soaps, frequent hand washing). 1, 3

First-Line Topical Treatment

For Localized Disease (<20% Body Surface Area)

• Apply mid-to-high potency topical corticosteroids such as triamcinolone 0.1% or clobetasol 0.05% to affected areas. 2
• Use soap substitutes and gentle cleansers instead of harsh soaps. 1, 3
• Apply moisturizers immediately after washing to repair the skin barrier—use two fingertip units for adequate hand coverage. 1, 3
• Package moisturizers in tubes rather than jars to prevent contamination. 1, 3

Critical Facial Precautions

• Exercise extreme caution with topical corticosteroids on facial skin—prolonged use causes skin thinning, telangiectasia, perioral dermatitis, and red face syndrome. 5, 6
• The face has increased percutaneous absorption, making it more susceptible to steroid-induced adverse effects. 6

Systemic Treatment for Extensive Disease

When to Escalate to Systemic Corticosteroids

• For allergic contact dermatitis involving >20% body surface area, systemic corticosteroid therapy is required and provides relief within 12-24 hours. 2
• For severe rhus dermatitis (poison ivy), taper oral prednisone over 2-3 weeks—rapid discontinuation causes rebound dermatitis. 2
• Avoid oral corticosteroids or immunosuppressants during patch testing; if unavoidable, keep prednisolone ≤10 mg daily. 3, 6

Diagnostic Workup When Cause is Unknown

• Refer for patch testing with an extended standard series of allergens if dermatitis persists despite treatment or if the causative agent remains unknown. 5, 1, 3
• Pattern and morphology of dermatitis, particularly on hands and face, is unreliable in distinguishing between irritant, allergic, or endogenous dermatitis. 5, 1, 3
• Do not apply potent topical steroids to the back within 2 days of patch testing—this causes false negatives. 3, 6
• For suspected drug eruptions, perform drug patch tests to determine whether the reaction was due to the active drug or excipients. 4

Second-Line Therapies for Refractory Cases

Topical Alternatives to Corticosteroids

• Consider topical tacrolimus 0.1% or pimecrolimus 1% where topical steroids are unsuitable, ineffective, or when chronic facial dermatitis raises concerns about steroid-induced skin damage. 5, 3, 6
• Topical tacrolimus has demonstrated effectiveness in nickel-induced allergic contact dermatitis models and avoids the atrophy risk of prolonged steroid use. 3, 6
• Application site burning occurs in 8-26% of patients treated with pimecrolimus, but discontinuation rates are comparable to placebo. 7

Systemic Therapies

• For severe chronic hand eczema, offer alitretinoin. 5
• Consider PUVA phototherapy for chronic contact dermatitis resistant to topical steroids. 5, 3
• For steroid-resistant cases, consider systemic immunosuppressants like azathioprine or ciclosporin. 3, 6

Critical Pitfalls to Avoid

What NOT to Do

• Do not use topical antibiotics (neomycin, bacitracin) without clear indication—they are common allergens themselves and can cause allergic contact dermatitis. 1
• Avoid washing with dish detergent or other known irritants, very hot or very cold water, and disinfectant wipes. 1, 3, 6
• Do not over-rely on barrier creams alone—they have questionable value in protecting against irritants and may create false security. 3
• Avoid prolonged occlusion without underlying moisturizer application. 3
• Antibiotics are not indicated for uncomplicated contact dermatitis—it is not an infectious condition. 1

Special Considerations for Drug Eruptions

• Antihistamines, especially hydroxyzine and cetirizine, are often not recognized as culprits in cutaneous eruptions—assess every patient whose skin condition worsens after antihistamine treatment. 8
• For NSAID-induced contact dermatitis, cross-reactivity within the same chemical class is well described; avoid topical and systemic administration of molecules in the sensitizing class. 5, 4
• A patient sensitized to corticosteroid ointment must be tested to determine which corticosteroid classes (A, B, C, D1, D2) are sensitizing—topical and systemic administration of molecules in sensitizing classes must be forbidden. 4

Protective Measures

• Use appropriate gloves based on specific exposures—rubber or PVC gloves with cotton liners for household tasks, neoprene or nitrile for latex allergy. 5, 1, 3
• Remove gloves regularly to prevent sweat accumulation, which aggravates dermatitis. 3
• Apply moisturizer before wearing gloves. 1, 3
• In occupational settings, select gloves based on chemical exposures and consider permeation time—"impervious" gloves have finite protection duration. 5, 3

Prognosis and Long-Term Outlook

• If the causative agent is completely avoided, contact dermatitis will clear. 3, 6
• The prognosis for occupational contact dermatitis is often poor: only 25% of patients achieve complete healing over 10 years, 50% have intermittent symptoms, and 25% have permanent symptoms. 1, 3
• Changing occupation does not improve prognosis in 40% of cases. 3
• Early identification and complete avoidance of allergens offers the best chance for resolution. 3