What is the treatment for discoid eczema?

Treatment of Discoid Eczema

First-Line Treatment: Topical Corticosteroids

Topical corticosteroids are the mainstay of treatment for discoid eczema, using the least potent preparation that effectively controls symptoms. 1

Corticosteroid Application Strategy

• Apply topical corticosteroids no more than twice daily to affected coin-shaped lesions 1
• Start with high or ultra-high potency topical corticosteroids for discoid eczema, as this condition typically requires stronger preparations than other eczema types 2
• Use potent corticosteroids (e.g., betamethasone dipropionate) or very potent corticosteroids (e.g., clobetasol propionate) for initial control 3
• Implement "steroid holidays" - stop corticosteroids for short periods when possible to minimize side effects 1
• Once daily application is likely as effective as twice daily for potent corticosteroids, though twice daily may be used initially for severe flares 3

Essential Skin Care Measures

• Apply emollients liberally and regularly, even when eczema appears controlled - this is the cornerstone of maintenance therapy 1
• Apply emollients after bathing to create a surface lipid film that prevents water loss 1
• Use dispersible cream as a soap substitute - avoid regular soaps and detergents that strip natural skin lipids 1
• Regular bathing is beneficial for cleansing and hydrating, but avoid extreme temperatures 1
• Keep nails short to minimize scratching damage 1
• Avoid irritant clothing like wool; prefer cotton 1

Second-Line Topical Treatments

For Lichenified (Thickened) Lesions

• Ichthammol 1% in zinc ointment is particularly useful for lichenified discoid eczema and is less irritant than coal tar 1
• Coal tar solution 1% in hydrocortisone ointment is generally preferred to crude coal tar 1
• These preparations do not cause systemic side effects unless used extravagantly 1

Managing Secondary Bacterial Infection

Watch for increased crusting, weeping, or pustules - these indicate secondary bacterial infection. 4

• Flucloxacillin is first-line for Staphylococcus aureus (the most common pathogen) 1
• Use erythromycin for penicillin allergy or flucloxacillin resistance 1
• Continue topical corticosteroids during bacterial infection when appropriate systemic antibiotics are given concurrently 4

Eczema Herpeticum (Medical Emergency)

• Suspect if you observe grouped vesicles, punched-out erosions, or sudden deterioration with fever 4
• Initiate oral acyclovir early in the disease course 4, 1
• Administer acyclovir intravenously in ill, feverish patients 4

Managing Pruritus

• Sedating antihistamines may help with nighttime itching through their sedative properties, not direct anti-pruritic effects 1
• Use primarily at night while asleep; avoid daytime use 1
• Non-sedating antihistamines have little to no value in discoid eczema and should not be used 4, 1

Patch Testing for Persistent Cases

Consider patch testing in all patients with severe or persistent discoid eczema - allergic contact dermatitis is relatively common (50% positive patch tests, 33% clinically relevant) 5

• Common allergens include rubber chemicals, formaldehyde, neomycin, chrome, and nickel 5
• Allergen avoidance may benefit 61% of patients with positive relevant patch tests 5

Systemic Therapy for Refractory Disease

Phototherapy

• Narrow band ultraviolet B (312 nm) is an option for widespread or refractory disease 4
• Some concern exists about long-term adverse effects including premature skin aging and cutaneous malignancies 4

Systemic Medications

• Methotrexate should be considered for moderate to severe pediatric discoid eczema failing conventional therapies - 64% achieved complete clearance after average 10.5 months at 5-10 mg weekly 6
• Systemic corticosteroids have a limited role - only for acute severe flares requiring rapid control when topical therapy has failed, for short-term "tiding over" during crisis periods 4
• Oral steroids should NOT be used for maintenance treatment 4

Critical Safety Considerations

Topical Corticosteroid Safety

• Risk of skin atrophy is low with intermittent use - only 1 case reported among 1213 patients using mild/moderate potency TCS over 5 years 7
• Avoid very potent corticosteroids in thin-skinned areas (face, neck, flexures, genitals) 4
• Potent and very potent corticosteroids should be used cautiously in children due to risk of pituitary-adrenal axis suppression 1
• Abnormal skin thinning occurred in only 1% of patients across trials, mostly with higher-potency preparations 3

Common Pitfalls to Avoid

• Do not delay or withhold topical corticosteroids when infection is present - they remain primary treatment when appropriate systemic antibiotics are given 4
• Patients' fears of steroids often lead to undertreatment - explain different potencies and benefits/risks clearly 4
• Do not use topical corticosteroids continuously without breaks 4

When to Refer or Escalate

• Failure to respond to moderate potency topical corticosteroids after 4 weeks 4
• Need for systemic therapy or phototherapy 4
• Suspected eczema herpeticum (medical emergency) 4
• Extensive disease or diagnostic uncertainty 1