Eczema (Atopic Dermatitis)

Eczema

What Is Nummular Eczema? Symptoms, Causes, Diagnosis, Treatment, and Prevention

Jessica Migala
By Medically Reviewed by 
Reviewed:
Medically Reviewed

Are you noticing circular, rough, red patches on your arms, hands, or legs? Do they itch like crazy? You may have a flare-up of nummular eczema (NE), a subtype of chronic eczema (or atopic dermatitis) that’s characterized by extremely itchy round or oval spots on the skin.

“[NE] is a manifestation of sensitive skin that is triggered by environmental factors, and it can also happen in almost anyone [with] poor skin care,” says Suzanne Friedler, MD, a board-certified dermatologist with Advanced Dermatology in New York City. NE can also occur in patients who regularly moisturize and practice good skin care, but whose skin lacks the proteins needed to lock moisture into the skin (such as collagen, elastin, and keratin).

To understand what NE is, exactly, look closely at the words. “Nummular means coin-like and eczema is sensitive skin. Therefore, people with NE display coin-shaped, itchy red patches on their skin,” Dr. Friedler says.

Although this condition is treatable, it can be incredibly uncomfortable because of the itch, and may return even after treatment.

Signs and Symptoms of Nummular Eczema

According to the National Eczema Association (NEA)

and the American Academy of Dermatology (AAD),

symptoms of NE include:
  • Coin-shaped lesions on the arms, legs, torso, or hands
  • Tiny bumps or blister-like sores
  • Spots that last for weeks or months
  • Itching, burning, or extremely dry skin
  • Lesions that are oozing liquid or crusted over
  • Red, pinkish, or brown skin that is scaly and inflamed around the lesions

Common Questions & Answers

What is the best treatment for nummular eczema?
Along with proper moisturization, your dermatologist may recommend a steroid or steroid-free topical cream. For severe cases of nummular eczema, phototherapy (which uses UV light) or systemic therapies may be an option.
Is nummular eczema an autoimmune condition?
Nummular eczema is a type of eczema, the exact cause of which is unknown. Triggers include dry air, stress, skin injury, and infection. Atopic dermatitis, the most common form of eczema, belongs to a group of chronic allergic conditions, including asthma, hay fever, and food allergies.
How do you stop nummular eczema from spreading?
You can help prevent more lesions from appearing with gentle skin-care steps, such as short, lukewarm showers, soaps designed for sensitive skin, and body cream applications throughout the day.
What triggers nummular eczema?
It is triggered by dry conditions, such as winter or forced heat indoors; perfumes and fragrances that irritate the skin; long, hot showers; or harsh skin-care products. If you have sensitive skin, you may have an increased risk of nummular eczema.
Is nummular eczema a fungus?
No, nummular eczema is not a fungus, and it is not contagious. It’s triggered by environmental factors, not a fungal infection, and presents as coin-shaped, itchy red patches on the skin.

Causes and Risk Factors of Nummular Eczema

If you have sensitive skin, you may also develop NE if you don’t take care. “NE is triggered by factors that cause dry skin,” says Friedler. If you have a history of skin reactions or eczema, be wary of taking long, hot showers, using harsh or strongly scented soaps, and allowing your skin to become too dry. You may also notice flare-ups during winter, when the air outside is cold and dry and the forced heat indoors is dry, too, notes Friedler.

How Is Nummular Eczema Diagnosed?

NE can be diagnosed via a visit to a board-certified dermatologist. Your doctor will be able to distinguish this type of rash from other causes, but it may not be that obvious to an untrained professional, so resist trying to diagnose it on your own.

“When you have one single patch, it could be caused by so many things, including a fungal infection or hives,” says Emma Guttman, MD, PhD, the chair of dermatology and immunology at the Icahn School of Medicine at Mount Sinai in New York City.

NE can also masquerade as psoriasis, ringworm, and other types of eczema, such as contact dermatitis.

Your dermatologist can confirm the cause with a physical exam, but they may want to confirm it by testing a skin scraping.

In a small number of cases, NE may be associated with a skin allergy, such as a nickel allergy, adds Dr. Guttman. “We would perform a patch test on these patients to identify any allergies,” she says. While most cases are not associated with skin allergy, she says it is still good practice to rule this out with a test.

Prognosis of Nummular Eczema

Even once NE is treated and goes away, there is a possibility it may come back. “Recovery and relapse depend on the person’s predisposition to sensitive skin — which is genetic — as well as their skin-care habits,” says Friedler.

Duration of Nummular Eczema

If you start seeing a dermatologist (who may prescribe topical creams) and switch to skin-care products formulated for sensitive skin, “NE can clear up within a few days to a couple of weeks,” Friedler says. Most cases of NE improve significantly within 7 to 10 days, but the actual duration of NE depends on how severe or widespread the rash originally was.

Treatment and Medication Options for Nummular Eczema

When you notice these telltale bumps or lesions, the treatment will generally be gentle skin care, says Friedler. She recommends the following steps:

  • Keep showers short. Stick to 10 minutes or less.
  • Shower with lukewarm to warm water.
  • Cleanse with soaps labeled for sensitive skin.
  • Avoid cleansing rash areas directly.
  • After your shower, when skin is damp, moisturize with a heavy cream to lock in hydration.
  • Reapply body cream throughout the day.
  • Wear soft, breathable fabrics.
  • Sleep with a humidifier in your bedroom.

Medication Options

If needed, your dermatologist may prescribe a topical steroid or steroid-free creams. “These will clear the rash quickly,” says Friedler. They will also help reduce inflammation and itching. An example of a topical steroid cream is a hydrocortisone cream. Crisaborole topical (Eucrisa) or pimecrolimus topical (Elidel) are steroid-free ointments approved for mild to moderate eczema.

Alternative Medicine Options

While having one or few patches makes you a good candidate for a topical cream, if you have a widespread or severe case, Guttman says your dermatologist may talk to you about phototherapy.

Phototherapy is light therapy that directs controlled wavelengths of UV light to the skin to soothe skin and ease itchiness.

(This is done in a controlled, in-office setting; going out in the sun will not effectively treat nummular eczema, and unprotected sun exposure can cause damage to the skin.)

“Phototherapy treatments penetrate the outer layers of skin and reduce inflammatory cells,” Guttman says. These treatments may be used all over skin, or a specific type of laser called an excimer laser can be used to target affected areas only, she adds.

Phototherapy may also be recommended if four weeks of topical treatment and proper skin care do not clear the coin-shaped patches, Guttman says.

Phototherapy requires commitment and may be burdensome, as patients often have to go to the office three times per week for treatment, says Guttman. What’s more, not every dermatologist office will offer phototherapy. Talk to your doctor about the right options for you.

Prevention of Nummular Eczema

To prevent future flare-ups of NE, practice the smart skin-care tips outlined above. That includes routine use of moisturizer, short showers, and use of a humidifier on cold, dry days.

If NE is caused by a contact allergy, avoid the triggering allergen to prevent a flare-up.

Complications of Nummular Eczema

If you scratch itchy patches of NE, you can open them up and expose them to bacteria from your hands and fingernails, leading to an infection.

Infected patches may appear as yellow or golden crusty areas, streaks of red or brown traveling away from the sore, or patches that are swollen or oozing pus. If you suspect you have an infection related to NE, call your doctor or dermatologist, who can treat you for the infection by prescribing a topical or oral medication.

In addition, NE is often infected with Staphylococcus aureus,

a type of bacteria that one-third of people naturally carry.

If that’s the case, treatment will need to target both NE and any co-occurring staph infections.
In rare cases, NE is also prone to a process called autoeczematization, in which there is diffuse spreading after a secondary trigger like a localized spot of severe eczema or a separate infection.

Research and Statistics: Who Has Nummular Eczema?

While nummular eczema can affect anyone of any age, it’s most often diagnosed in men over age 50 and women who are teenagers or young adults.

The size of the lesions that affect people with nummular eczema ranges from 1 to 10 centimeters (cm).

BIPOC and Nummular Eczema

NE is a type of eczema, or atopic dermatitis, and eczema is the second most common skin disease among African Americans.

This is because of genetic mutations among certain ethnic groups that compromise the skin barrier.

Eczema can appear differently in Black, Indigenous, and People of Color (BIPOC) populations compared with those with white skin. For people with skin of color, eczema can look ashen, brown, or grayish. What’s more, there is also an increased risk of skin discoloration following flare-ups or after itchy patches are scratched.

Related Conditions and Causes of Nummular Eczema

It’s unclear exactly what causes NE. Factors that can contribute to the condition include:

  • Dry skin caused by cold, dry weather
  • Sensitive skin
  • Other types of eczema, such as contact dermatitis
  • Trauma to the skin (a bug bite, scrape, chemical burn, or skin infection)
  • Contact allergies to materials like nickel
  • Poor blood flow in the lower body
  • Intense stress
  • Heavy alcohol consumption
  • Medications that dry out skin as a side effect, including diuretics and statins
  • Genetics

Resources We Love

Favorite Orgs for Eczema Info

American Academy of Dermatology

The AAD supplies need-to-know info on nummular eczema, eczema, and general skin health.

National Eczema Association

Learn about the seven types of eczema, including nummular eczema. After reading about NE, stay on the site for more about living with eczema, patient stories, and new treatments in development.

HealthyChildren.org

Eczema often starts in childhood. If your child has eczema, this site (from the American Academy of Pediatrics) has a handy list of symptoms to help parents understand the signs, triggers, and treatment for this condition, plus information on when to call the pediatrician and photos to help with identification.

Favorite App to Help Heal Your Skin

EczemaWise

Developed by the National Eczema Association, this smart tool can help you track your symptoms and identify your diet and lifestyle triggers. The app is available on the Apple App Store and Google Play.

Favorite Online Support Network

MyEczemaTeam

MyEczemaTeam is a social network and online support resource with over 35,000 members that you can turn to for answers, advice, and tips for overcoming the challenges of living with eczema.

Editorial Sources and Fact-Checking

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