Nummular Eczema (Discoid Eczema): Causes, Treatment and How to Stop Coin-Shaped Patches Coming Back
Eczema guide
Nummular eczema, also called discoid eczema, causes round or oval, coin-shaped patches of itchy, inflamed skin, usually 1 to 10 cm across. The patches most often appear on the lower legs, then the arms, and can ooze or crust when active. It is linked to very dry skin, and contact allergy is common. With the right treatment patches can clear within a few weeks, but it often comes back, so daily moisturising and avoiding triggers are just as important as treating a flare.
- Look for: sharply defined, coin-shaped patches that are very itchy, often several and on both sides of the body.
- Common triggers: dry skin, hot baths, harsh soaps, contact allergens such as nickel, formaldehyde and fragrance, stress and alcohol.
- Treatment: strong anti-inflammatory creams prescribed by a doctor for flares, plus daily moisturising to prevent relapse.
- Rule out ringworm: a fungal rash can look similar, and steroid creams make it worse.
- Long-term care: thick, fragrance-free moisturisers, lukewarm showers and gentle, steroid-free creams between flares.
What is nummular eczema?
Nummular eczema (from the Latin nummulus, "small coin") is a long-lasting type of eczema that forms round, well-defined patches. It is less common than atopic eczema: a German study of national health insurance data estimated it affects about 0.26% of people, with peaks in older men and in young children (Hagenström et al., 2026). Unlike typical atopic eczema, many adults with nummular eczema have no history of childhood eczema. Read about the other forms in types of eczema.
What does nummular eczema look like?
- Round or oval, coin-shaped patches, usually 1 to 10 cm across, with a sharp edge (Leung et al., 2020)
- Several patches, often on both sides of the body, most commonly on the lower legs, then the forearms, hands and trunk
- Intense itch; in a study of 100 adults, itch was the symptom that most affected quality of life (Jiamton et al., 2013)
- When active, patches can be bumpy, blistered, oozing or crusted; older patches turn dry, scaly and darker
- Generally dry skin around the patches
On darker skin, patches may look dark brown, purple or grey rather than red, and can leave darker or lighter marks after they heal.
What causes nummular eczema?
The exact cause is not known, but several factors are linked to it:
- Very dry skin: two-thirds of patients in one study also had generally dry skin (Jiamton et al., 2013).
- Contact allergy: in North American patch-testing data, nearly 1 in 4 people with nummular eczema also had allergic contact dermatitis. The most relevant allergens were formaldehyde and formaldehyde releasers, the preservative methylisothiazolinone, fragrance and propylene glycol (Silverberg et al., 2021). Nickel was the most common allergen in a Thai study (Jiamton et al., 2013).
- Hot baths and harsh soaps, which strip the skin's oils (Leung et al., 2020).
- Stress and alcohol, which patients report make it worse (Jiamton et al., 2013).
- Skin injury, such as scratches, insect bites or burns, which can trigger new patches.
- Bacterial infection: weeping, crusted patches can become infected with Staphylococcus.
If you suspect a product or metal is involved, see contact dermatitis.
Is it nummular eczema, ringworm or psoriasis?
| Condition | Typical look | Clues |
|---|---|---|
| Nummular eczema | Evenly inflamed coin-shaped patch; may ooze or crust | Several patches, very itchy, dry skin, often on the legs |
| Ringworm (tinea corporis) | Ring with a raised, scaly edge and a clearer centre | Usually one or a few rings that spread outward; may follow contact with pets |
| Plaque psoriasis | Thick, raised plaque with silvery-white scale | Elbows, knees and scalp; nail pitting; family history |
Because ringworm can look similar, doctors recommend a simple skin scraping test if there is any doubt (Leung et al., 2020). This matters: steroid creams treat nummular eczema but can make a fungal rash spread. See ringworm and the psoriasis guide.
How is nummular eczema treated?
There are no formal guidelines yet, but a 2026 European expert consensus and earlier reviews agree on the main approach (Deleuran et al., 2026; Leung et al., 2020):
- Calm the flare: nummular eczema often needs a stronger prescription anti-inflammatory cream than other eczema types, usually a potent topical steroid for a short course. Non-steroid prescription creams such as calcineurin inhibitors are alternatives, especially for longer use.
- Repair the barrier: moisturise the whole body every day, not just the patches.
- Treat infection if patches are weeping, crusted or painful; a doctor may prescribe an antibiotic.
- Find the trigger: if it keeps coming back, ask about patch testing for contact allergy (Silverberg et al., 2021).
- Severe or widespread cases may be treated with light therapy or tablets and injections under a dermatologist.
Patches often clear within a few weeks of proper treatment, but the condition tends to relapse (Leung et al., 2020). Many people want to limit strong steroids once the flare settles; see natural alternatives to steroid cream and natural vs steroid creams.
What daily skin care helps prevent flares?
- Moisturise twice a day with a thick, fragrance-free cream or ointment, especially after washing. Moisturisers reduce eczema flares and the amount of medicated cream needed (van Zuuren et al., 2017).
- Short, lukewarm showers, not hot baths, then pat dry.
- Gentle, soap-free wash and fragrance-free laundry products.
- Check your products for formaldehyde releasers, methylisothiazolinone and fragrance, and avoid nickel against the skin if you react to it.
- Protect the skin from scratches and dryness in winter; use a humidifier if the air is dry.
- Manage stress and limit alcohol, both reported triggers.
How can you soothe nummular eczema itch?
- Cool compresses for 10 minutes on itchy patches.
- Keep nails short and cover patches at night if you scratch in your sleep.
- Use a cooling, steroid-free cream on dry, itchy patches between flares. Borneol and menthol act on the skin's cold receptors to ease itch (Tian et al., 2023).
- Avoid applying anything that stings to raw, weeping or cracked patches until they settle.
More ideas in how to stop itching naturally.
When should you see a doctor?
- Patches are weeping, crusted, painful or spreading, or you have a fever
- No improvement after 2 to 3 weeks of good skin care
- You are not sure if it is eczema, ringworm or psoriasis
- It keeps coming back, so patch testing may help
- Itch is disturbing your sleep or daily life
QICAOGANGMU: steroid-free care between flares
QICAOGANGMU combines She Chuang Zi, Ku Shen and Bai Bu with cooling borneol and menthol in a moisturising petrolatum and glycerin base. It is steroid-free (TÜV SÜD PSB found none of eight corticosteroids) and suits daily use on dry, itchy coin-shaped patches once they are no longer raw or weeping. Use it alongside your doctor's treatment, and patch test first.
Frequently asked questions
What is the main cause of nummular eczema?
There is no single cause. It is linked to very dry skin, contact allergy (for example to nickel, formaldehyde releasers or fragrance), hot baths and harsh soaps, skin injury, stress and alcohol.
Is nummular eczema contagious?
No. It is not an infection and cannot spread to other people, although weeping patches can become infected with bacteria.
How long does nummular eczema last?
With proper treatment, patches often clear within a few weeks, but it tends to come back. Daily moisturising and avoiding triggers help keep it away.
How do I tell nummular eczema from ringworm?
Ringworm usually has a raised, scaly edge with a clearer centre and spreads outward, while nummular eczema is evenly inflamed and often oozes or crusts. A doctor can confirm with a quick skin scraping.
Can I use QICAOGANGMU on nummular eczema?
Yes, on dry, itchy patches that are not raw or weeping, as steroid-free daily care alongside your doctor's treatment. Patch test first, and stop if it stings.
Related articles
References
- Leung AKC, Lam JM, Leong KF, et al. Nummular eczema: an updated review. Recent Pat Inflamm Allergy Drug Discov. 2020;14(2):146-155. PMID 32778043
- Deleuran M, Eyerich K, de Bruin-Weller M, et al. European consensus recommendations for nummular eczema: a modified Delphi study. J Eur Acad Dermatol Venereol. 2026 (online ahead of print). PMID 42411804
- Jiamton S, Tangjaturonrusamee C, Kulthanan K. Clinical features and aggravating factors in nummular eczema in Thais. Asian Pac J Allergy Immunol. 2013;31(1):36-42. PMID 23517392
- Silverberg JI, Hou A, Warshaw EM, et al. Prevalence and trend of allergen sensitization in patients with nummular (discoid) eczema referred for patch testing: North American Contact Dermatitis Group data, 2001-2016. Contact Dermatitis. 2021;85(1):46-57. PMID 33634511
- Hagenström K, Müller K, Klinger T, et al. Epidemiology of nummular eczema: methodological approaches and outcomes from nationwide claims data analyses. J Dtsch Dermatol Ges. 2026;24(7):886-893. PMID 41243467
- van Zuuren EJ, Fedorowicz Z, Christensen R, et al. Emollients and moisturisers for eczema. Cochrane Database Syst Rev. 2017;2:CD012119. PMID 28166390
- Tian W, He D, Liu J, et al. Topical borneol relieves nonhistaminergic pruritus via targeting TRPA1 and TRPM8 channels in peripheral nerve terminals of mice. Eur J Pharmacol. 2023;953:175833. PMID 37290679
Product information. This article is educational and does not replace medical advice. QICAOGANGMU is a topical herbal skin-care cream and does not cure eczema. See a doctor for patches that are spreading, weeping or not improving.
