Nummular eczema is a type of skin condition that can cause a ringworm-like rash. It leads to the formation of oval or coin-shaped patches, which can easily be mistaken for a ringworm rash. One symptom that can help differentiate between the two is that ringworm often produces a scaly, ring-shaped rash, usually on the trunk, arms, or legs. However, nummular or “discoid” eczema can also cause a round, scaly rash that looks like ringworm.
Nummular eczema (dermatitis) and ringworm are both skin conditions that can cause redness, itching, and other symptoms. People sometimes confuse these conditions because both can cause circular skin rashes. The rash can develop several red, raised rings at once, some of which may overlap. Although ringworm can develop almost anywhere on the body, it is most commonly found in the arms, legs, and trunk.
But if it's not ringworm, what else could it be? There are a variety of other skin conditions that could be causing a rash for you or your child. The two most common conditions are nummular eczema and annular granuloma. Nummular eczema causes circular patches of dry skin that may burn or become dry and scaly. This type of skin condition is often triggered by insect bites, certain medications, or an allergy to metals. Granuloma annuloma causes red or flesh-colored bumps to appear on the skin, but because they often look like rings, this condition can be confused with ringworm.
Everything from medications and viral infections to skin trauma and thyroid disorders can trigger granuloma annuloma. Other less common symptoms that may resemble ringworm include nummular eczema and dyshidrotic eczema. Nummular or discoid eczema is seen as circular, irritated skin reactions. The circular shape often causes it to be misdiagnosed as a more serious problem, such as ringworm. Both eczema and ringworm tend to inflame and redden the skin and can cause it to dry, swell, crust, and itch.
Symptoms of eczema include redness, dry skin, swelling of the affected area, suppuration, and crusting if scratched. But did you know that there are different types of eczema? If you don't realize what type you have, you may not understand what causes it or how to treat it. Some people with discoid eczema also have a history of atopic eczema, which often occurs in people who are prone to asthma and hay fever. If the eczema patches are substantially watery and oozing, applying an astringent compress can help dry the area and eliminate any staph infection. If you've noticed small itchy blisters on your hands or feet, you may suffer from dyshidrotic eczema. Doctors diagnose eczema largely by observing it and eliminating other possible causes of its symptoms.
Occasionally, areas of the skin affected by discoid eczema may become permanently discolored after the condition has disappeared. If nummular eczema is affecting your life, your dermatologist may prescribe oral or topical corticosteroids or recommend phototherapy, a treatment that involves exposing your skin to UV light. You can also try topical corticosteroids or other types of steroids that are applied directly to the eczema-affected area (topical), but they may have some side effects and shouldn't be used too often, especially in children.