Nummular eczema, also known as discoid eczema or nummular dermatitis, is a chronic skin condition that results in itchy, coin-shaped spots or patches on the skin. These patches most commonly appear on the legs, arms, torso, and hands. While the exact cause is often unknown, it often develops after a skin injury such as a cut or insect bite.

This condition tends to recur, especially in people with allergies or a history of other eczema types. Fortunately, with proper treatment and a dedicated skincare routine, most people can effectively manage symptoms and prevent flare-ups.

Nummular eczema symptoms

The hallmark symptom of nummular eczema is the formation of red, oval, or coin-shaped lesions ranging from 2 to 10 centimeters in diameter. A person may develop just one lesion or up to 50, and the spots can expand or merge to form larger patches.

These spots typically appear on:

  • Legs

  • Arms

  • Torso

  • Hands

  • Buttocks

Other common symptoms include:

  • Intense itching, especially at night

  • Burning or stinging sensations

  • Dry or scaly skin

  • Fluid-filled lesions that ooze and later crust over

  • Skin discoloration as lesions heal, often more noticeable in people with darker skin

What causes nummular eczema

Triggers for nummular eczema can vary widely between individuals. Some potential causes include:

  • Skin trauma such as cuts, scrapes, insect bites, or chemical burns

  • Very dry skin

  • Emotional stress

  • Extreme weather, either hot or dry

  • Excessive alcohol intake

  • Past skin infections

  • Medications that dry the skin, such as diuretics or statins

In some cases, the condition may appear alongside or following other types of eczema, like contact dermatitis after allergen exposure.

Risk factors

While anyone can develop nummular eczema, certain factors increase the risk:

  • Age: It is more common in men over 50 and women under 30. Though rare in children, kids with severe atopic dermatitis may be more susceptible.

  • Family history: Those with a family history of eczema, asthma, or allergies have a higher chance of developing it.

  • Underlying skin conditions: People with atopic or contact dermatitis and those with poor blood circulation in the legs are at increased risk.

How is nummular eczema diagnosed

To confirm a diagnosis, it’s important to consult a dermatologist. The process typically includes a review of medical history, a physical examination of the skin, and additional diagnostic tests to rule out other conditions.

Skin biopsy
A small sample of affected skin is removed and examined under a microscope to rule out other conditions like ringworm.

Skin culture
This test helps determine whether a bacterial infection is present in the eczema-affected area.

Patch testing
This allergy test involves applying small amounts of potential allergens to your skin. The patches are left in place for 48 hours, then removed to observe any reactions.

Treatments for nummular eczema

Though there is no cure, various treatment options are available to manage the condition. The type of treatment depends on the severity of the symptoms.

Skin hydration
Keeping the skin moisturized is essential to reduce flare-ups. Dermatologists often recommend fragrance-free, hypoallergenic creams or ointments.

Tips for effective hydration include:

  • Bathing or showering with lukewarm water

  • Adding bath oil to the water

  • Using a cool-mist humidifier in dry environments

Corticosteroids
These medications help calm the immune system and reduce inflammation. Options include:

  • Topical corticosteroids: Applied directly to affected areas, often after bathing

  • Oral corticosteroids: Used for more extensive symptoms

  • Injected corticosteroids: Reserved for severe cases needing stronger relief

Other medications
If corticosteroids are ineffective or not suitable, your healthcare provider may prescribe:

  • Tacrolimus ointment: A calcineurin inhibitor that suppresses inflammation

  • Pimecrolimus cream: Another calcineurin inhibitor that reduces the immune response

  • Coal tar cream: Helps relieve thickened, itchy patches

Phototherapy
This treatment uses UV light to reduce inflammation and itching. A moisturizing oil is often applied before treatment, and protective goggles are worn during sessions. Several treatments over one to two months are usually required.

Antibiotics
Scratching eczema patches can lead to bacterial infections, especially from staph bacteria. Signs of infection include redness, warmth, and pus. Depending on severity, your provider may prescribe topical or oral antibiotics.

How to prevent nummular eczema

Preventing flare-ups involves managing your skin health and avoiding known triggers. Key prevention strategies include:

  • Applying fragrance-free moisturizers or oils daily

  • Using lukewarm water for bathing or showering

  • Choosing gentle, unscented soaps

  • Wearing loose, breathable clothing such as cotton

  • Avoiding wool, spandex, and synthetic fabrics

  • Using dye-free and fragrance-free laundry products

  • Managing stress through mindfulness or relaxation techniques

  • Limiting alcohol intake

  • Visiting a dermatologist regularly for skin evaluations

Related conditions

People with nummular eczema often have or are at higher risk for other conditions due to overlapping immune responses or genetic factors.

Asthma
Individuals with nummular eczema are more likely to have asthma, a condition that narrows the airways and makes breathing difficult.

Mental health conditions
The discomfort from chronic itching and visible skin changes can lead to anxiety or depression.

Allergies
Up to half of those with nummular eczema also have allergies, such as reactions to foods, pollen, pets, or insect stings.

Living with nummular eczema

Living with nummular eczema can be frustrating, especially when it interferes with sleep or daily activities. The key to managing the condition lies in identifying and avoiding triggers while staying consistent with treatment.

It may take time to discover what worsens your symptoms. For some, it could be climate conditions; for others, personal care products or clothing fabrics. Working closely with a dermatologist will help you create an effective plan to reduce flare-ups and improve your quality of life.