Nummular eczema, also known as nummular dermatitis or discoid eczema, is a chronic condition that produces coin-shaped spots on the skin. These spots are often itchy and may ooze or become crusty.
Most common in elderly men, nummular eczema is a relatively uncommon condition that is not contagious.
There is no known cause of nummular eczema. Many people with nummular eczema also have a personal or family history of allergies, asthma, or atopic dermatitis (a skin condition that causes itchy or scaly rashes). Often, people with nummular eczema have sensitive skin that is easily irritated.
The following reportedly worsens symptoms:
- temperature changes (especially hot or cold conditions)
- dry skin
- environmental irritants, such as soaps, detergents, metals, and formaldehyde
Rarely, a medication allergy may be implicated.
The following conditions may increase your risk of developing nummular eczema:
- living in a cold, dry climate
- having dry skin
- having poor blood flow or swelling in the legs
- having another type of eczema or dermatitis
- having injured skin (from an injury, insect bite, or allergic reaction)
- having a bacterial infection on the skin
The most common and noticeable symptom of nummular eczema is coin-shaped lesions on the body. They frequently occur on the arms or legs but could spread to the torso as well. The lesions may be brown, pink, red, itchy, oozing, crusty, or scaly. The skin on and around the lesions may be red, raw, scaly, or inflamed.
To diagnose nummular eczema, your doctor will ask about your family medical history and visually inspect your skin. Skin biopsies (removal of a small piece of skin to be tested) may be used to help rule out other conditions, such as an infection.
If your doctor suspects the lesions are a result of an allergic reaction, he or she may do allergy testing as well. This may include skin tests, blood tests, or elimination and challenge tests to determine what, if any, substances you are allergic to.
There is no known cure for nummular eczema. However, lifestyle changes and avoiding triggers are the best ways to manage the condition.
To help control your nummular eczema, avoid:
- wool and other irritants that trigger your symptoms
- excessive bathing and hot water because it dries out the skin
- using harsh soaps
- exposure to environmental irritants (cleaners, chemicals, etc.)
- using fabric softener and dryer sheets
- scrapes, cuts, and abrasions on the skin
To help relieve your eczema:
- use moist bandages to cover and protect the affected areas
- take antihistamines to relieve itching and discomfort
- use medicated lotions or skin ointments (as prescribed in severe cases)
- ultraviolet light treatment for severe itching
- cortisone (ointment, injection or pills) may help treat severe outbreaks
Because nummular eczema is a chronic condition, it may never go away completely. It is best to avoid triggers that make your symptoms worse. Some lesions may go away completely, while others may come and go.
If left untreated, a secondary infection of the skin could develop. If infected, a yellowish crust will form on the infected lesion. If this occurs, your doctor may prescribe an antibiotic.