Read on to find out more about ringworm and nummular eczema. This article looks at symptoms, causes, treatment options, when to contact a doctor, and more.
Ringworm and nummular eczema can look similar in appearance, but they also have notable differences.
Ringworm
Ringworm of the body, or tinea corporis, is a contagious infection that leaves an itchy, ring-shaped patch on the skin. It typically forms in the exposed areas of the torso, neck, and limbs.
The Centers for Disease Control and Prevention (CDC) lists the typical symptoms of ringworm in specific areas of the body as follows:
- Tinea pedis: This refers to ringworm on the feet. It can cause:
- redness or discoloration and swelling
- peeling
- itchy skin between the toes
- blistering, in severe cases
- Tinea capitis: This is ringworm of the scalp. It usually looks like a scaly, itchy bald spot that is red or discolored. This spot can grow in size and multiply. This most commonly affects children.
- Tinea cruris: This describes ringworm on the groin, sometimes called jock itch. It usually looks like scaly, itchy spots that are red or discolored.
- Tinea barbae: This is when ringworm forms under a person’s beard. Symptoms include scaly, itchy spots that are red or discolored, as well as crusting and pus.
Additional symptoms of ringworm can include cracked skin and hair loss. Symptoms of ringworm typically appear within 4–14 days of infection, according to the CDC.
Learn more about where in the body ringworm can affect.
Nummular eczema
Nummular eczema, also called discoid eczema or nummular dermatitis, is a skin condition that causes itchy, coin-shaped patches on the skin. It usually affects the legs, but it can occur in other areas.
The American Academy of Dermatology Association (AAD) provides the typical signs of nummular eczema as follows:
- tiny bumps and blister-like sores, which are often the first sign
- coin-shaped raised spots
- itchiness
- extremely dry skin
- infection, which can look like yellow or golden crusts on the spots
Learn more about the symptoms of nummular eczema.
How ringworm and eczema look on different skin tones
Nummular eczema can look different on different skin tones. People with darker skin tones may develop brown, purple, or pale spots. People with lighter skin tones may instead experience pink or red spots.
Ringworm can also look different in different skin tones. It typically looks red or pink on light-colored skin and brown or gray on darker skin.
The table below provides additional facts about ringworm versus eczema.
| Ringworm | Nummular eczema | |
| Appearance | causes ring-like spots on your skin | causes coin-shaped spots on your skin |
| Cause | results from a fungal infection | has an uncertain origin |
| Transmission | is contagious | is not contagious |
| Treatment | responds to antifungal drugs | responds to thick emollients |
View the slideshow below for photos of ringworm and nummular eczema.
Ringworm and nummular eczema have different causes.
Ringworm
Ringworm results from infection with certain types of fungi, including Trichophyton rubrum, Trichophyton mentagrophytes, and Microsporum audouinii.
There are three main ways ringworm can spread:
- Contact with a person who has ringworm: This may occur through clothing, towels, and other personal items.
- Contact with an animal that has ringworm: Many types of animals can spread ringworm to people, including dogs, cats, and goats.
- Contact with infected surfaces: Ringworm fungi can live on surfaces, especially in damp areas such as public showers and locker rooms.
The following factors may also increase your risk of ringworm:
- living in a tropical area
- being in hot, humid weather
- having obesity
- having diabetes
- taking part in a contact sport
- wearing tight clothing
Learn more about skin infections.
Nummular eczema
There is currently no known clear cause of nummular eczema.
However, there is sufficient evidence that some factors can act as triggers, including:
- having contact dermatitis
- having a scratch, an insect bite, a thermal burn, or other similar injuries
- having impetigo or a wound infection
- having dry skin
- having varicose veins
Certain medications may also trigger nummular eczema. These include:
- interferon and ribavirin when you use both together to treat hepatitis C
- tumor necrosis factor-alpha (TNF-alpha) blockers, an arthritis medication
- taking statins, which are cholesterol-lowering medications
Ringworm and nummular eczema have different treatments.
Ringworm
Dermatologists typically treat ringworm with over-the-counter (OTC) and prescription antifungals. These could be gels, creams, or spray solutions.
Types include:
- miconazole
- clotrimazole
- ketoconazole
- naftifine
- terbinafine
- oral terbinafine or itraconazole for widespread infections
Learn more about ringworm treatments.
Nummular eczema
Treatment for nummular eczema focuses on restoring the natural skin barrier and reducing dryness. Your dermatologist will typically recommend thick emollients, such as petroleum jelly (Vaseline). They may also provide antibiotics if you have signs of bacterial infection.
Additional remedies include:
- Topical corticosteroids: These reduce inflammation and itching.
- Topical calcineurin inhibitors: These reduce symptom flares.
- Sedating antihistamines: These can reduce eczema-related sleep problems and relieve itchiness associated with eczema.
- Narrowband UVB light therapy: This uses a special light to clear the patches.
- Systemic immunosuppressants and immunomodulators: These reduce inflammation, irritation, and itching.
These at-home remedies may also help clear nummular eczema:
- applying undiluted sunflower oil directly to the skin immediately after bathing
- putting virgin or cold-pressed coconut oil onto the patches
- applying cold compresses to the affected skin
Contact your doctor if you have been treating ringworm or eczema with OTC medications for some weeks and have not seen improvement.
If you have symptoms of infection, such as pus or fever, seek immediate treatment.
Your doctor or dermatologist may be able to diagnose ringworm and nummular eczema by performing a physical examination and asking you questions about your symptoms.
They may also perform a biopsy to confirm the diagnosis. This involves removing a sample of your skin to study it more closely under a microscope.
If your doctor or dermatologist suspects ringworm, they may also take swabs from the affected area to identify the type of infection.
Ringworm and nummular eczema are two separate skin conditions with some similar features.
Ringworm is a contagious infection that leaves an itchy, ring-shaped patch on the skin. It results from a fungal infection. Nummular eczema is a skin condition that causes itchy, coin-shaped patches on the skin. It has an unclear cause.
Dermatologists use antifungals to treat ringworm. They recommend gentle skin care, routine emollient use, and sometimes topical or oral medications to treat eczema.
Contact your doctor if you have symptoms of ringworm or eczema. They will be able to confirm the diagnosis and advise on treatments.
