Treatment of Nummular Eczema
The treatment of nummular eczema primarily involves topical corticosteroids as the mainstay therapy, 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 Emollients
- Regular bathing is beneficial for both cleansing and hydrating the skin, with emollients applied afterward to provide a surface lipid film that retards evaporative water loss 1
- Patients should avoid soaps and detergents that remove natural skin lipids and use dispersible cream as a soap substitute 1
- Apply emollients after bathing to lock in moisture 2
- Patients should 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 mild nummular eczema, start with mild-potency topical corticosteroids 2
- Apply a thin layer to affected areas only, no more than 3-4 times daily 3
- Once daily application of potent topical corticosteroids is likely as effective as twice daily application 4
- Treatment should not be applied more than twice daily, as this doesn't improve efficacy but increases risk of side effects 1, 2
- Corticosteroids should be stopped for short periods when possible to minimize side effects 1
Management of Itch
- Sedating antihistamines provide the most effective symptomatic relief for pruritus 2
- Antihistamines are primarily valuable for their sedative properties during severe pruritic episodes 1
- Use sedating antihistamines primarily at night while asleep, with daytime use being avoided 1, 2
- Non-sedating antihistamines have little to no value in treating nummular eczema 1, 2
Second-Line Treatment
Coal Tar and Ichthammol Preparations
- Ichthammol (1% in zinc ointment) is less irritant than coal tars and particularly useful for lichenified eczema 5, 1
- Coal tar solution (1% in hydrocortisone ointment) is generally preferred to crude coal tar 5, 1
- These preparations do not cause systemic side effects unless used extravagantly 5, 1
Infection Management
- Antibiotics are important for treating overt secondary bacterial infection 5, 1
- Flucloxacillin is usually most appropriate for Staphylococcus aureus (the most common pathogen) 5, 1
- Phenoxymethylpenicillin should be given if β-hemolytic streptococci are isolated 5, 1
- Erythromycin may be used when there is resistance to flucloxacillin or in patients with penicillin allergy 5, 1
- Herpes simplex infection (eczema herpeticum) requires oral acyclovir early in the disease course 5, 1
- Consider dental infections as a potential aggravating factor in treatment-resistant cases 6
Prevention of Flare-ups
- Weekend (proactive) topical corticosteroid therapy probably results in a large decrease in likelihood of relapse compared to no topical corticosteroids 4
- Keep nails short to minimize damage from scratching 1, 2
- Avoid extreme temperatures and irritant clothing, such as wool, with cotton clothing being preferred 1
Special Considerations
- In children, topical corticosteroids should be used cautiously due to the risk of pituitary-adrenal axis suppression 5, 1
- Children under 2 years of age should only use hydrocortisone under medical supervision 3
- Systemic corticosteroids have a limited role and should only be considered after all other treatments have been explored 5, 1
- For treatment-resistant cases in adults with atopic dermatitis with nummular phenotype, dupilumab (an IL-4/IL-13 inhibitor) has shown effectiveness 7
When to Refer
- Most patients respond well to first-line management and don't require specialist referral 5, 1
- Consider referral for patients with treatment failure, extensive disease, or diagnostic uncertainty 1
- Emotional stress and alcohol consumption may aggravate the disease and should be addressed 8