An Overview of Nummular Eczema

Nummular eczema is a type of eczema that is distinguished, in large part, by coin-shaped (round or oval) spots on the skin. The rash can be itchy or not, dry or wet, and cause significant discomfort.

Treating nummular eczema is difficult, as it does not affect everyone who has it in the same way, and its root cause is not known.

Symptoms

Though nummular eczema can appear anywhere on the body, the condition typically affects the arms and legs.

Round, disc-like lesions that are pink, red, or brown in color are to be expected. Other symptoms, which can vary from person to person, include:

• Itchiness at the rash site (possibly only when lesions are developing)
• Liquid drainage at the rash site
• Crusting over of the lesions
• Redness of skin surrounding the rash
• Pain

Nummular eczema can also be the cause of emotional stress because of its appearance.

Causes

Experts do not believe that nummular eczema has familial underpinnings, but the exact reason why the condition occurs is not clear.

Different conditions may contribute to or aggravate nummular eczema. These include:

• Contact dermatitis
• Dry skin
• Weather
• Emotional stress
• Oral medications including interferon (usually used to treat hepatitis) or isotretinoin (a popular acne medication)
• Topical medications including antibiotic creams like Neosporin
• Previous skin damage including a burn, puncture wound, open skin from scratching, or an insect bite

Nummular eczema is more likely to affect men between the ages of 55 and 65. Women generally experience their initial nummular eczema episode between the ages of 15 and 25.

Diagnosis

Accurate diagnosis of nummular eczema can be difficult as the rash may appear different on different skin types. If the condition is suspected, your healthcare provider will conduct a close examination of your skin and your questions that may provide useful clues, including some related to recent exposures/activities, your history of skin trauma, other health conditions, and so on. Testing may also be necessary.

Patch Test

A patch test to look for contact dermatitis may be beneficial for patients with nummular eczema. This helps determine if any personal products or other agents that you are exposed to could be worsening your rash. The most common culprit is nickel, but fragrances, rubber products, and other substances can be problematic as well.

The patch test is a three-day test. On the first day, adhesive sheets containing multiple patches are placed on your back. Each patch is impregnated with a common allergen. These are left on your skin for 48 hours.

It is important not to get your back wet with water or sweat during this time, as it can interfere with the patches and lead to inaccurate results.

After 48 hours, the healthcare provider will remove the patches and look for signs of redness, irritation, and rash. Another reading will be done at the three-day mark. Any reaction to a patch is considered "positive," meaning you have an allergy to that particular substance.

While nummular eczema is not an allergic condition itself, specific skin allergies can trigger a nummular eczema flare-up as well as prevent existing flares from healing. Having a positive patch test is helpful because it means you can identify and avoid products that are worsening your eczema.

Skin Biopsy

Your healthcare provider may need to rule out other skin diseases that resemble nummular eczema. This is done with a skin biopsy, which is typically performed in the physician's office with local anesthesia.

The sample is turned over to a pathologist to examine the skin under a microscope; certain conditions are easily distinguishable when looking, for example, at the arrangement of cells.

Differential Diagnoses

The most common diagnosis nummular eczema gets confused with is a fungal skin infection, specifically tinea corporis or ringworm. Ringworm infections are also circular-shaped and extremely itchy, which adds to the confusion between the two.

Other skin conditions that may resemble nummular eczema include:

• Plaque psoriasis
• Contact dermatitis (irritant or allergic)
• Stasis dermatitis
• Lichen simplex (this condition often occurs alongside chronic nummular eczema)
• Pityriasis rosea
• Drug eruptions (skin rash caused by a reaction to a medication)

The treatment for individual rashes differs greatly, so it is important to see a healthcare provider for the correct diagnosis.

Treatment

Nummular eczema is considered a chronic condition that alternates between periods of flaring and inactivity.

Regardless of where you are in that cycle, it is important to avoid exacerbating factors, including stress, whenever possible, and to keep the skin hydrated.

Apply a thick layer of a fragrance-free, hypoallergenic cream or ointment to the rash at least three times a day, but as often as necessary. This helps with the dryness associated with nummular eczema and, in turn, can help soothe the itch. There are many over-the-counter creams that fit the bill. Ask your healthcare provider or pharmacist for recommendations.

In addition, there are several topical medications that can help treat this skin condition.

Steroid Medications

Topical steroids are the first-line treatment for nummular eczema. Generally, a strong topical steroid is needed to help resolve the rash.

Topical steroids have important side effects, including:

• Hyper or hypopigmentation (darkening or lightening of the skin, respectively)
• Telangiectasias (enlarged blood vessels, usually capillaries)
• Skin atrophy (skin thinning)
• Easy bruising
• Increased risk of skin infection

Typically, you will only experience these side effects if you use topical steroids for a prolonged period of time or on injured skin, although the potency of the medication you receive can also increase your risk.

Your healthcare provider may ask you to be extra cautious in areas like the face, neck, underarms (axilla), and groin area, as skin is thinner in there and more likely to suffer from the adverse effects listed above.

Oral steroids may also be helpful if the rash is worse than usual. However, these drugs are not usually the best treatment option because they can worsen dermatitis after you taper off of them.

Nonsteroidal Medications

There are other treatment options for nummular eczema. These agents are not steroids, so they carry much fewer adverse effects. However, they may not be as helpful as topical steroids.

Protopic (tacrolimus) and Elidel (pimecrolimus) belong to a class of medications called topical calcineurin inhibitors. Topical calcineurin inhibitors work by suppressing part of the immune system and blocking the chemicals responsible for triggering an eczema flare-up. It is important to note that these topical creams can cause burning after application.

Eucrisa (crisaborole) is a nonsteroidal topical medication that may be helpful in those who are unable to use topical steroids. Eucrisa works by blocking specific enzymes that cause inflammation of the skin.

Cibinqo (abrocitinib) and Rinvoq (upadacitinib), both JAK inhibitors, work by targeting enzymes that, research suggests, play a role in driving the abnormal immune responses seen in autoimmune conditions, like eczema. They are taken as a single tablet, once per day. Both are approved for adults with moderate to severe atopic dermatitis (if the condition is not well-controlled with other drug treatments) but Rinvoq is also approved for people ages 12 and up. 

Antihistamines can also be used to relieve itching resulting from nummular eczema. Examples include Zyrtec (cetirizine), Allegra Allergy (fexofenadine), Xyzal (levocetirizine), and Claritin (loratadine).

Treating Infection

Because nummular eczema damages the skin's barrier, it leaves the skin open to bacterial invasion. If the rash becomes infected, it can look and feel worse (i.e., more red, inflamed, and painful).

Usually, the most common organism found in culture is Staphylococcus aureus. If found, it will require additional treatment, most likely with an oral antibiotic.

Coping

One of the most difficult things to deal with during a flare of nummular eczema is the itching. This can be intense to the point of interfering with your daily activities and your ability to sleep.

To combat this symptom:

• Use Wet Wraps or Ice Packs: These can be placed over any itchy areas of the skin. Wet wraps can be left overnight if needed. If you're using icepacks, make sure you're placing a cloth between your skin and the ice.
• Keep Your Skin Covered While You Sleep: Wear long pajamas, ideally made from a soft fabric, or cover the rash loosely with a bandage. This can help prevent you from scratching at the rash while you sleep and causing damage to the skin.

If itching is unbearable, talk to your healthcare provider about other ways to cope.

Manage Stress

Stress seems to be a big trigger for nummular eczema flares. Besides, the condition itself can cause stress thanks to the itching, discomfort, and embarrassment it can cause. Stress management helps you feel better and can help your skin too.

Take time for self-care. This includes getting enough sleep and exercise, drinking plenty of water, and eating healthy foods. Taking care of yourself physically makes you feel better all around.

Engage in stress-relieving activities. Anything that makes you feel happy, healthy, and contented, make time to do more of it. This can include yoga, reading, gardening, sports, or meditation.

Talk to your healthcare provider about your mental health. If you are struggling with anxiety, overwhelming stress, or depression, let your healthcare provider know. There are medications and lifestyle changes that can help.

Find Support

It's also common for people with nummular eczema to feel self-conscious or embarrassed about the rash. You may feel like others are staring at your skin, are judging you, or avoiding you because they think it may be contagious. This alone can make you feel stressed and discouraged.

Finding support is key, especially if your nummular eczema is severe or long-lasting, as these can take a toll on your mental well-being. Talking to trusted people in your life can help. Also, you may wish to reach out to others who know what you're going through.

Online support can be found through the National Eczema Association. If you live in a larger metropolitan area, you may also be able to find a local support group. Ask your healthcare provider for recommendations.

A Word From Verywell

Nummular eczema can be a frustrating condition to deal with. With the right combination of treatment and personal care, though, it can be brought under reasonable control. For some people, the skin may be cleared altogether. Talk to your healthcare provider in order to get help and support.