Nummular Eczema: Symptoms, Causes, Risk Factors, Diagnosis, Treatment and Outlook

It is also known as nummular dermatitis or discoid eczema; it is a chronic condition that causes coin-shaped spots on the skin.

These spots are often intense and well-defined. They can ooze clear liquids or become dry and crisp.

Nummular eczema often appears after an injury to the skin, such as a burn, abrasion, or insect bite. The condition can result in a patch or multiple patches of coin-shaped lesions.

Nummular eczema tends to occur more often in men than women. Men generally have their first episode between the ages of 55 and 65.

Women generally have it during adolescence or early adulthood. Although the symptoms of nummular eczema can be bothersome, they can be treated with medicines and topical medications.

It is not contagious, which means it cannot be passed from one person to another through direct contact with the skin.

What are the symptoms?

The most common and noticeable symptom of nummular eczema is a coin-shaped patch of lesions on the body. Lesions frequently develop on the arms or legs but can eventually spread to the torso and hands. They can be brown, pink, or red.


Other lesions may ooze fluid and eventually crust over. The skin around the lesions may be red, scaly, or inflamed.

Call your doctor if you think you have nummular eczema. If left untreated, a secondary skin infection could develop. Once this occurs, a yellowish crust will form on the infected lesions.

What Causes Nummular Eczema?

There is no known cause for nummular eczema. However, many people with nummular eczema have a personal or family history of allergies, asthma, or atopic dermatitis.

Atopic dermatitis is a skin condition that causes itchy or scaly rashes. People with nummular eczema also tend to have sensitive skin easily irritated.

The following factors can also contribute to the development of nummular eczema:

  • Changes in temperature
  • Stress.
  • Dry Skin.
  • Environmental irritants, such as soaps, metals, and formaldehyde.

Who is at risk for nummular eczema?

The following conditions can increase your risk of developing nummular eczema:

  • Live in a cold and dry climate.
  • Have dry skin
  • Having poor blood flow or swelling in the legs.
  • Have another type of eczema.
  • Having a skin injury, such as an insect bite or abrasion.
  • Having a bacterial infection that affects the skin.

How is nummular eczema diagnosed?

Your doctor may be able to diagnose nummular eczema by asking about your medical history and visually inspecting your skin. They may also want to do a skin biopsy to help rule out other possible conditions, such as an infection.

During the biopsy, the doctor will remove a small piece of skin tissue from the affected area. The sample will be tested for the presence of bacteria.

If your doctor suspects that the lesions result from an allergic reaction, they may also perform an allergy test. This may include skin tests or blood tests that can help determine what substances you are allergic to.

How is it treated?

There is no cure for nummular eczema. However, you may be able to manage your condition by making specific lifestyle changes and avoiding triggers.

To help control your nummular eczema, you should avoid:

  • Wool and other irritants can trigger your symptoms.
  • Excessive bathing and hot water.
  • Use strong soaps.
  • Stressful situations.
  • Exposure to environmental irritants, such as household cleaners and chemicals.
  • Use of fabric softener and dryer sheets.
  • Get scrapes, cuts, and abrasions on the skin.

The following can help ease your eczema:

  • Use wet bandages to cover and protect the affected areas.
  • Take antihistamines.
  • Apply medicated lotions or ointments to the skin.
  • Receive ultraviolet light treatment for severe itching.
  • Moisturize skin with an unscented moisturizer after you shower.

What’s the outlook for people with nummular eczema?

With proper treatment, nummular eczema can improve within a year. However, nummular eczema is a chronic condition, so it may never resolve. Some lesions can go away completely, while others can come and go.

Injuries to the thighs, legs, and feet often take longer to heal and can leave darker or lighter spots. It’s best to avoid triggers that make your symptoms worse.