Nummular Eczema: Causes, Symptoms, Treatment Options, and Flare Management

Most people have heard about eczema—and the dry, itchy skin it causes. Less well-known is a particular kind of eczema called nummular eczema. While it’s not as common as some other types of eczema, it’s just as troublesome when not well-managed. 

Getting your condition under control means working with a team of specialized dermatologists who have deep experience managing flare-ups of nummular eczema understand—and know the best nummular eczema treatment options and approaches to give you lasting relief.  

While nothing can replace the individualized guidance of a specialist, covering the basics here is a good place to start—including everything from how to identify nummular eczema to the most effective treatments for nummular eczema. 

What Is nummular eczema?

“Nummular eczema is a subtype of eczema that presents as coin-shaped plaques or raised, red itchy areas, predominantly on the legs,” Dr. Day says. About that funny name: The word nummular originates from Latin and means “resembling coins.”

You’re more likely to develop this kind of eczema if you already have dry skin or atopic dermatitis (the most common type of eczema, per the Cleveland Clinic.) It’s also more common in older white men, Dr. Day says (though it also happens in women, younger people, and people of color). 

Like all eczemas, nummular eczema flares involve skin inflammation and a dysfunctional skin barrier, Dr. Day says. Your skin barrier, made of fats, proteins, and dead skin cells, is the outermost protective layer of your skin. A healthy skin barrier acts like a coat of armor, shielding the vulnerable skin underneath from things that could trigger your immune system while keeping moisture in. 

In nummular eczema, that layer of armor is leaky. As moisture escapes, the skin barrier becomes dehydrated, less resilient, and prone to micro-cracks, Dr. Day explains. Irritants, allergens, and bad bacteria can penetrate the skin barrier—triggering an inflammatory response that results in a flare. A porous skin barrier might let irritating perfume molecules or staph bacteria through, Dr. Day says, causing a flare-up or infection. 

Causes of nummular eczema

The causes of nummular eczema aren’t fully understood, but include genetic and environmental factors. 

Genes

While there’s no single gene for nummular eczema, there are several that make you more likely to develop it, Dr. Day says. (For instance, a mutation in the gene that produces filaggrin, a protein in your skin barrier.) You’re also more prone to nummular eczema if you have a personal or family history of atopic dermatitis, asthma, or allergies.

Environment

Your genes interact with the environment they’re exposed to—from the climate you live in, to the microbiome (the ecosystem of microbes, like bacteria) in your gut, Dr. Day says. These factors can switch on the genes that make you vulnerable. 

Symptoms of nummular eczema and diagnosis

Let’s talk about how to identify nummular eczema. The main symptoms of nummular eczema are those unique, coin-shaped rashes. Raised and sometimes scaly, they cause serious itching, per the American Academy of Dermatology. The surrounding skin may be extremely dry.

At first, you might just notice tiny bumps, maybe after a cut or scrape. These bumps merge into rashes, ranging in size from a dime to a half dollar, Dr. Day says. On lighter skin, the rashes are pink or red; on darker skin, they can appear brown or lighter than your skin tone.

Nummular eczema can actually look like psoriasis in its early stages, according to the Mount Sinai Health System, but there are a few key psoriasis and nummular eczema differences. Psoriasis plaques are well-defined. “In nummular eczema, the edges of the rash are less crisp and bleed into the normal skin,” Dr. Day says. Plus, psoriasis tends to appear around your knees, elbows, and scalp, while nummular eczema usually stays on the lower legs.

A dermatologist can diagnose you by taking a look at your skin and asking you about the symptoms of nummular eczema. They may also ask about your family history or test a small skin sample. 

Effective nummular eczema treatment options

There are many effective nummular eczema treatment options—from a smart skincare routine that strengthens your skin barrier, to prescriptions that calm inflammation. 

A Hydrating  skincare routine

Effective treatment for nummular eczema starts with a solid over-the-counter routine. “The foundation of treatment is maintaining a healthy skin barrier,” Dr. Day says. That means using ingredients that hydrate and fortify the skin barrier daily.

Moisturizers are your best friend. The best moisturizers for nummular eczema are creams and ointments, which are more gentle and hydrating than lotions, the National Eczema Association explains. Dr. Day recommends looking for two kinds of ingredients: 

• Humectants (like hyaluronic acid and glycerin) draw water into your skin. 
• Emollients (like shea butter and coconut oil) soften and soothe skin. They form a film that locks moisture in. 

The very best moisturizers for nummular eczema contain ceramides, a superstar emollient. Natural ceramides make up about half of your top skin layer, but get depleted in eczema. Applying synthetic ceramides can “keep the seal of the skin barrier healthy,” Dr. Day says. A study comparing four emollients found that only ceramides kept skin moisturized for 24 hours. 

Meanwhile, avoid irritating ingredients in moisturizers and body washes, like fragrances, salicylic acid, and harsh soaps, Dr. Day says. 

You might also want to play it safe by avoiding essential oils and botanical ingredients in case you’re allergic. Stick with gentle, fragrance-free, and/or hypoallergenic products (from brands like Vanicream, Cerave, and Cetaphil) and look for the National Eczema Association seal.

Make your bathing routine eczema-friendly, too. The American Academy of Dermatology recommends that you: 

• Use warm water, as very hot water is drying.
• Cap showers and baths at 20 minutes.
• Moisturize after bathing, when skin is still slightly moist.

Prescription topical medications

The next category of effective treatments for nummular eczema is prescription topicals, which reduce skin inflammation. They include:

• Topical steroids: This first-line therapy is “very effective,” Dr. Day says. However, long-term use can cause side effects.
• Non-steroid topicals: The next line of treatment is usually a calcineurin inhibitor, Dr. Day says. These treat and prevent flares by blocking immune system activation. Another good option is phosphodiesterase inhibitors. 

Systemic therapies

You probably won’t need systemic (meaning whole body) treatment because nummular eczema typically affects a smaller area, Dr. Day says. But if you also have atopic dermatitis, systemic treatments can help reduce inflammation all over. They include:

• Phototherapy: Certain wavelengths of light reduce the skin’s inflammatory response, the National Eczema Society explains. 
• Biologics: Injectables target specific parts of your immune system. 
• JAK inhibitors: These oral medications interrupt signals in the inflammatory process.

Managing and preventing flares

Keeping your skin happy requires more than great treatment. Another component of nummular eczema flare management is identifying and avoiding your unique triggers and allergens, Dr. Day says. 

In eczema, your immune system tends to treat minor irritants and allergens like harmful germs—reacting with a big inflammatory response that causes a flare. Many people with nummular eczema also have sensitivities or allergies (contact, seasonal, or food), Dr. Day says. For instance, research shows that anywhere from 30% to 78% of people with nummular eczema have contact allergies. 

Many triggers in your everyday environment can cause flares—like pollen, mold, dust mites, chemicals, and fumes from cars or factories, according to the National Institute of Allergy and Infectious Diseases. Your doctor might perform patch testing to figure out your allergies. 

Food sensitivities or allergies can also trigger nummular eczema. Dairy and eggs are common culprits, but it’s “very individual-specific,” Dr. Day says. She recommends keeping a food diary and eliminating a potential trouble food for a few weeks before reintroducing it, and seeing if it triggers a flare. 

Other possible causes of nummular eczema flares include anything that causes skin dryness, irritation, or overheating—think winter weather, medications that dehydrate skin (like statins), bug bites, heat and humidity, rough or synthetic fabrics (like wool and spandex), and even dry indoor air. (Wearing soft, breathable fabrics like cotton and using a home humidifier can help with those last two.) 

Managing flare-ups of nummular eczema is easier with the support of a dermatologist who knows how to identify nummular eczema triggers and spends time helping you find yours. “You want someone who can help you understand how different things you're experiencing are interconnected,” Dr. Day says. 

Impact on quality of life

Quality of life can be “hugely impacted,” Dr. Day says. The itchy rashes make it hard to concentrate, relax, get a good night’s sleep, and feel confident in your appearance. In a survey of 530 people, 66% said their eczema makes them feel lonely, while 61% said it causes them trouble falling or staying asleep at least once a week. 

That’s why having a team to help you master nummular eczema flare management doesn’t just improve your skin—it has positive ripple effects throughout your life. 

Lifestyle changes

Certain lifestyle changes can do a lot to prevent flares and enhance your quality of life. 

Managing stress

Emotional and mental stress can show up as nummular eczema flares, Dr. Day says.

How does stress impact your skin? The stress response triggers a cocktail of inflammatory chemicals to be released throughout your body. For instance, the hormone cortisol messes with oil production in your skin, causing irritation, while histamine (released by your immune system in allergic reactions) creates itchiness.

It’s a vicious cycle: Stress triggers a flare, causing more stress, triggering another flare. So one of the most powerful ways to get your skin under control is to get your stress levels under control.

Managing your stress with self-care and professional support improves nummular eczema flare management, according to the American Academy of Dermatology. One 2022 review of 26 studies found that a variety of psychotherapeutic approaches—like mindfulness, meditation, music therapy, and traditional therapy—improved eczema, as well as mental health. 

Healthy habits 

Cutting out habits that raise body inflammation and adding in habits that lower it can boost your nummular eczema flare management. “It’s all connected,” Dr. Day says.

• Nix smoking and drinking: They’re hard on your body and cause inflammation.
• Eat well: Dr. Day recommends replacing processed foods (which are pro-inflammatory) with fresh, whole foods like fruits and veggies (which are anti-inflammatory). 
• Supplement your diet: Certain supplements, like prebiotics and probiotics (which enhance the health of your gut microbiome), may help decrease inflammation. 
• Work out: Exercise can reduce inflammation, research suggests. 
• Drink plenty of water: This keeps your body hydrated from the inside out—skin included. 

To tackle nummular eczema, you want an expert team specialized in treating individuals with your condition, like the dermatologists at Zest. They’ll work closely with you to create a skincare routine that supports a healthy skin barrier, choose effective treatments, identify your triggers, and make lifestyle changes—so you can prevent flares and get back to enjoying your life more.