What is the recommended treatment for nummular eczema?

Treatment of Nummular Eczema

Topical corticosteroids are the mainstay of treatment for nummular eczema, with the least potent preparation required to control symptoms being recommended, along with proper skin hydration and avoidance of irritants. 1

First-Line Treatment

Skin Care and Avoidance of Triggers

• Avoid soaps and detergents that remove natural skin lipids; use dispersible cream as a soap substitute 1
• Avoid extreme temperatures and irritant clothing (especially wool); cotton clothing is recommended 1
• Keep nails short to minimize damage from scratching 1
• Identify and avoid specific triggers that may worsen symptoms, such as emotional stress and alcohol 2

Bathing and Emollients

• Regular bathing is beneficial for both cleansing and hydrating the skin 1
• Apply emollients after bathing to provide a surface lipid film that retards evaporative water loss 1
• Allow patients to determine the most suitable bath oil and bathing regimen for their condition 1

Topical Corticosteroids

• Use the least potent preparation required to keep the eczema under control 1
• For moderate to severe nummular eczema, moderate to potent topical corticosteroids are more effective than mild preparations 3
• Once-daily application of potent topical corticosteroids is likely as effective as twice-daily application 3
• When possible, corticosteroids should be stopped for short periods to minimize side effects 1
• Treatment should not be applied more than twice daily 1

Second-Line Treatment

Ichthammol and Tar Preparations

• Ichthammol (1% in zinc ointment) is less irritant than coal tars and particularly useful for lichenified eczema 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

Antihistamines

• Primarily valuable for their sedative properties during severe pruritic episodes 1
• Useful as short-term adjuvants to topical treatment during relapses with severe itching 1
• Non-sedating antihistamines have little to no value in treating nummular eczema 1
• Should be used primarily at night while asleep; daytime use should be avoided 1

Management of Secondary Infection

• Antibiotics are important for treating overt secondary bacterial infection 1
• Flucloxacillin is usually most appropriate for Staphylococcus aureus (most common pathogen) 1
• Phenoxymethylpenicillin for β-hemolytic streptococci; erythromycin for penicillin allergy 1
• Herpes simplex infection (eczema herpeticum) requires oral acyclovir early in the disease course 1

Advanced Treatment Options

Proactive Therapy

• Weekend (proactive) application of topical corticosteroids significantly reduces relapse rates compared to reactive treatment 3

Considerations for Referral

• Most patients respond well to first-line management and don't require specialist referral 1
• Consider referral for patients with treatment failure, extensive disease, or diagnostic uncertainty 1

Important Caveats

• Abnormal skin thinning is a potential side effect of topical corticosteroids, with risk increasing with higher potency preparations 3
• Patch testing should be considered in patients with chronic, recalcitrant nummular eczema as contact allergy is common 4
• The condition often follows a chronic course with relapses and remissions, requiring ongoing management 4, 2
• Nummular eczema significantly impacts quality of life, particularly due to itching 2

Special Populations

• In children, topical corticosteroids should be used cautiously due to risk of pituitary-adrenal axis suppression 1, 5
• Systemic corticosteroids have a limited role and should only be considered after all other treatments have been explored 1