Medically reviewed by: Ted Schiff, MD
What is nummular eczema?
Nummular eczema, also called discoid eczema or nummular dermatitis, is an inflammatory skin condition that causes an itchy, red, circular rash. It’s named after the Latin word for “coin-like” since the lesions that make up the rash are often round like coins.
The condition can develop at any time, but it most often appears in women between ages 15 and 25 and in men between ages 50 and 65. It’s more common in men.
What causes nummular eczema?
The cause of nummular eczema is unclear. It’s more common in people with allergies, asthma and certain other types of eczema—specifically atopic dermatitis (the most common type), stasis dermatitis or contact dermatitis. Having a relative with atopic dermatitis, hay fever or asthma increases the risk of nummular eczema. People with poor blood flow to the legs are more vulnerable to developing nummular eczema on the legs.
A handful of nummular eczema triggers have been identified. They include:
- Skin injury (a cut, bite, etc.) or infection
- Dry air
- Heat and humidity
- Severe stress
- Heavy alcohol use
- Very dry skin (xerosis cutis)
- Medications that can cause very dry skin, such as diuretics used to treat high blood pressure and cholesterol-lowering statins
Nummular eczema symptoms
The first signs of nummular eczema are tiny bumps and blister-like sores that may burn, sting and itch intensely. The bumps ooze a clear fluid, crust over, and join others to form larger, slightly raised round or oval lesions. The lesions range in size from 1 to 4 inches across and have clearly defined edges. It’s possible to have as many as 50 nummular eczema lesions at a time.
Lesions most often appear on the forearms, legs or backs of the hands, and they affect both sides of the body. They’re pink or red in people with lighter skin and brown or lighter than the natural skin color in people with darker skin. The skin between the lesions is usually very dry.
Nummular eczema vs. ringworm
Diagnosing nummular eczema can be challenging because it can resemble other skin conditions, particularly ringworm. A fungal infection, ringworm also causes an itchy and scaly circular rash. Even the color of the lesions is similar. But ringworm typically involves only one or two spots. The spots have a bumpy border and are paler in the center.
Unlike ringworm, eczema is not a fungus.
Is nummular eczema contagious?
Nummular eczema does not spread from person to person. No form of eczema is contagious.
Nummular eczema treatment
Nummular eczema is typically more stubborn than other forms of eczema and rarely goes away without treatment. Topical eczema medications are the most common treatment. They include corticosteroid ointment, tar cream, tacrolimus ointment and pimecrolimus cream. These medications reduce itching and inflammation.
If you’ve scratched your lesions so much that they become infected, you may also need a topical or oral antibiotic. Signs of infection include yellow or golden crusts on the lesion, swelling, pus, and red streaks or, in darker skin, brown streaks.
If the lesions are widespread, your dermatologist might recommend an oral or injectable corticosteroid, which is stronger than topical corticosteroids. Phototherapy, also called ultraviolet light therapy, is another treatment option for some people.
Nummular eczema self-care
You can help reduce the symptoms of nummular eczema by making some changes to your daily routines.
- Moisturize throughout the day, especially after bathing. The best moisturizer for nummular eczema is a thick, fragrance-free cream or an ointment such as petroleum jelly, not a lotion.
- Shorten your baths and showers to avoid drying out your skin. Use lukewarm (not hot) water and a mild, fragrance-free, non-soap cleanser.
- If the air in your house is dry, run a humidifier in your bedroom to help keep your skin hydrated.
- Wear loose-fitting clothing made of cotton or another soft fabric.
- Reduce stress.
- Avoid scratching or rubbing your skin.
Nummular eczema pictures
What does nummular eczema look like? See these photos for examples.
Nummular eczema on a leg
Closeup of a nummular eczema lesion
If you or a loved one has a rash that could be nummular eczema, schedule an appointment to get an accurate diagnosis and appropriate treatment.