What Is Nummular Eczema?
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Medically reviewed by William Truswell, MD
Nummular eczema, also called discoid eczema or nummular dermatitis, is a chronic skin condition that causes itchy, coin-shaped spots or patches to appear on the skin. Patches most commonly appear on your legs, arms, torso, and hands. The exact cause of nummular eczema is often unknown, but it tends to appear after a skin injury like a cut or bug bite.
This condition tends to recur (happen again), especially among people who have allergies or other forms of eczema. Treatments for nummular eczema are highly effective at clearing your skin and providing relief. A proactive skincare routine and working closely with a dermatologist (a doctor specializing in treating skin, hair, and nail conditions) can also help prevent flare-ups.
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Nummular Eczema Symptoms
The most common symptom of nummular eczema is the appearance of red, oval, or coin-shaped spots (lesions) ranging in size from 2 to 10 centimeters (cm) in diameter. People with nummular eczema may have between one and 50 spots at a time, which can grow and merge into patches. If you develop nummular eczema, it’s common to develop spots or patches on the following body parts:
Legs
Arms
Torso
Hands
Buttocks
Other symptoms of nummular eczema include:
Intense itchiness that often worsens at night
Burning or stinging sensations
Dry or scaly skin
Fluid that oozes out from the lesions and eventually crusts over
As the lesions begin to heal, they flatten and may leave spots of discolored skin that are lighter or darker than your surrounding skin. It’s worth noting that skin discoloration from nummular eczema spots is more common in people with darker skin tones.
What Causes Nummular Eczema?
Nummular eczema triggers can vary from person to person and may include:
Skin trauma, including cuts, scrapes, insect bites, and chemical burns
Extremely dry skin
Stress
Dry air
Living in hot or humid weather
Drinking excess alcohol
History of skin infections
Medications that cause dry skin, such as diuretics (water pills) and statins (cholesterol-lowering drugs)
In some cases, nummular eczema develops in response to other types of eczema. For example, people who have contact dermatitis can experience symptoms of nummular eczema after coming into contact with an allergen (such as nickel or pollen).
Risk Factors
Anyone can develop nummular eczema, but certain factors can increase your risk. These include:
Age: Nummular eczema is more common among males over 50 and females under 30. It is rare in children, but kids with severe atopic dermatitis may have a higher risk.
Family history: A family history of allergies, asthma, or atopic dermatitis increases your risk of this condition.
Underlying conditions: People with atopic or contact dermatitis are more likely to develop nummular eczema. Poor circulation (blood flow) to your legs also increases your risk of developing this chronic skin condition.
How Is Nummular Eczema Diagnosed?
If you are experiencing symptoms of nummular eczema, it’s important to see your primary care provider or dermatologist to get the proper treatment you need. Dermatologists are the primary healthcare providers who can diagnose and treat nummular eczema. At your appointment, your dermatologist will ask you about your symptoms, review your medical history, and examine your skin.
Symptoms of nummular eczema are similar to those ofin other skin conditions, including atopic dermatitis and ringworm. Your dermatologist will likely order diagnostic tests to rule out other possible causes of your symptoms and confirm a nummular eczema diagnosis. These tests may include:
Skin biopsy: Your healthcare provider will remove a small sample of the affected skin with a scalpel or razor blade and examine it under a microscope. This test helps rule out other possible causes, such as ringworm.
Skin culture: If your healthcare provider suspects you have a skin infection, they may swab and test the affected skin area to confirm your diagnosis.
Patch testing: This exam is a type of allergy test that involves applying tiny amounts of possible allergens to the skin on your back. After keeping the patches on your skin for 48 hours, your dermatologist will remove them and look for signs of allergic reactions in response to the allergens. Depending on how your skin reacts to the allergen, your provider may ask you to come in for another follow-up appointment to check for signs of a late allergic reaction.
Treatments for Nummular Eczema
Unfortunately, there is no cure for nummular eczema at this time. But treatments can help reduce inflammation and relieve discomfort. There are a variety of treatments available, but your exact treatment plan will depend on the severity of your condition. In most cases, your provider will prescribe you a combination of treatments to keep symptoms at bay.
Skin Hydration
Dry skin can worsen nummular eczema symptoms or trigger flare-ups. Your dermatologist may recommend applying a hypoallergenic, fragrance-free moisturizing cream or ointment to your skin throughout the day to help trap moisture and promote healing.
Keeping your skin well-hydrated may also involve:
Bathing or showering daily in lukewarm water
Adding bath oil to your bathwater
Using a cool mist humidifier in your bedroom to keep the air moist
Corticosteroids
Corticosteroids are prescription medications that suppress overactive immune responses. As a result, this can reduce inflammation and itchiness. Corticosteroids come in different forms, and the type your healthcare provider prescribes will depend on the severity of nummular eczema. Types of corticosteroids include:
Topical: Topical corticosteroid creams or ointments are medicines you apply directly to the affected areas of the skin. Your healthcare provider may recommend applying these immediately after showering or bathing.
Oral: More widespread nummular eczema may require oral corticosteroids that you take by mouth to reduce inflammation.
Injection: Severe nummular eczema may require injected corticosteroids to help reduce inflammation and ease symptoms.
Other Medications
Your healthcare provider may prescribe other topical medications to treat nummular eczema if corticosteroids are ineffective or cause unwanted side effects, such as:
Tacrolimus ointment: Protopic (tacrolimus) ointment is a medication in a class of drugs called calcineurin (a protein that contributes to inflammation in eczema) inhibitors. These medicines help prevent your immune system from causing inflammation.
Pimecrolimus cream: Elidel (pimecrolimus) cream is a calcineurin inhibitor that suppresses an overactive immune response to reduce nummular eczema symptoms.
Coal tar cream: These creams can help relieve inflamed, itchy skin. Healthcare providers may prescribe coal tar cream, gel, or ointment to treat eczema patches that are thicker than usual.
Phototherapy
Phototherapy (light therapy) uses different wavelengths of ultraviolet (UV) light to reduce skin inflammation and soothe symptoms like itching. Healthcare providers may recommend phototherapy for widespread nummular eczema or when topical treatments are ineffective.
During phototherapy treatment, a provider will apply a moisturizing oil to the affected areas of your skin. Your healthcare provider will ask you to wear goggles to protect your eyes from the ultraviolet rays. Most phototherapy sessions only take minutes to complete, though you may need several treatments over one to two months to see improvements.
Antibiotics
People with nummular eczema are prone to developing secondary bacterial infections — most commonly Staphylococcus aureus (staph) infections. S. aureus bacteria naturally live on the skin of 80% of people with eczema. Scratching or rubbing itchy eczema patches can introduce these bacteria deeper into yourthe skin, causing infection.
If you have signs of a bacterial infection, such as increased redness, warmth, or pus-filled blisters on your eczema patches, your provider may prescribe you topical or oral antibiotics, depending on the severity of your infection.
How To Prevent Nummular Eczema
Nummular eczema is a chronic condition that has periods of remission (when symptoms go away with treatment) and flare-ups (when symptoms return). Maintaining a skincare routine that keeps your skin healthy and being aware of possible triggers can help prevent nummular eczema flare-ups. This may include:
Applying fragrance-free creams, ointments, or body oils daily to keep your skin well-hydrated
Showering or bathing in lukewarm water and avoiding hot water that dries out your skin
Using fragrance-free, hypoallergenic, and gentle soaps to cleanse your skin
Wearing loose-fitting clothing made of breathable factors (e.g., cotton) and avoiding wearing wool or other rough-textured fabrics, such as nylon, spandex, and polyester
Trying dye-free, fragrance-free laundry detergents
Visiting your healthcare provider regularly to monitor your skin health and adjust your treatment plan as needed
Engaging in stress management techniques, such as yoga, meditation, or breathing exercises
Limiting your alcohol intake
Related Conditions
People with nummular eczema, are more likely to have or develop other related conditions, particularly allergic diseases. Research is ongoing, but some evidence suggests that genetic factors and immune dysfunction may play a role in the connection between these conditions and eczema.
Asthma: Research shows that people with nummular eczema are three times more likely to have asthma than the general population. Asthma is an inflammatory condition that causes your airways to swell and narrow, making breathing difficult.
Mental health conditions: People with nummular eczema have an increased risk of developing mental health conditions, such as depression and anxiety. Chronic itching and discomfort can contribute to stress and emotional distress, possibly contributing to or worsening emotional symptoms.
Allergies: Up to 50% of those with nummular eczema have allergies, which can include food allergies, seasonal allergies (e.g., hay fever), pet allergies, insect stings, or allergies to certain chemicals that lead to contact dermatitis.
Living With Nummular Eczema
When you live with nummular eczema, the relentless itching and discomfort can disrupt your sleep and daily activities. The discomfort can take a toll on your overall well-being. The good news is that proactive skincare practices can reduce the frequency of flare-ups.
Knowing and avoiding your triggers is one of the best ways to reduce flare-ups, but it may take some time before you can identify them. For some people, this may involve wearing cotton clothing and avoiding extreme weather temperatures. For others, avoiding perfumes and personal care products with fragrance and other added chemicals may help.
When flare-ups occur, ask your healthcare provider to work with you to find effective treatments for symptom relief and clearing your skin. Doing so can help you improve symptoms and better your quality of life.
Frequently Asked Questions
Is nummular eczema a fungal infection?
No, nummular eczema is not a fungal infection. It is a form of eczema that develops due to an overactive immune response. Certain triggers, such as coming into contact with an allergen or stress, can lead to nummular eczema, though in some cases, the cause is unidentified.
What happens if nummular eczema is not treated?
Nummular eczema does not usually go away without treatment. Untreated nummular eczema can worsen itching, discomfort, and cracked skin, increasing the risk of secondary bacterial infections.
Can nummular eczema spread to other body parts?
Yes, nummular eczema can spread to other body parts. Although it is not contagious and does not spread from person to person, people with nummular eczema may notice new patches appearing as others in a different area of the body heal.
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