Nummular Eczema - Causes, Symptoms, and Treatment

What Is Nummular Eczema?

Nummular Eczema is a type of dermatitis characterized by coin-shaped, round, or oval patches of dry, itchy skin. These patches can contain fluid. The term nummular derives from the Latin word for “coin” because the patches are coin-shaped. The patches are usually well-defined and can become crusty (scab-like) and/or scaly. Nummular eczema will not spread from person to person. It is also considered to be a chronic condition.

Who Is Affected by Nummular Eczema?

Nummular eczema can affect individuals of any age, with males being more frequently affected than females, especially in middle-aged and older adults. In younger age groups, the gender difference is less pronounced.

What Distinguishes Nummular Eczema From Ringworm?

Both ringworm (tinea corporis) and nummular eczema have the same shape but are treated differently. Ringworm (tinea corporis) is highly contagious and caused by a fungus, while nummular dermatitis is an eczema-like condition caused by irritation and not by a fungus.

Ringworm typically presents with a clearer center and a more raised, active scaly border, whereas nummular eczema patches are usually uniformly inflamed and may ooze or crust. Nummular eczema usually has multiple lesions, while ringworm typically has only one or two.

What Causes Nummular Eczema?

Nummular eczema's cause is presently unknown, but it is a combination of several factors:

• Family or personal history of allergies such as asthma or eczema.
• Stress.
• Temperature changes.
• Dry skin.
• Environmental irritants include metals, harsh soaps, and formaldehyde.

Common triggering factors include:

• Heat and humidity.
• Skin injury or infection, such as a bug bite or scrape.
• Alcohol.

Nummular eczema has been shown to correlate strongly with impaired skin barrier function and dry skin (xerosis), especially during the winter months.

Who Is at Risk for Nummular Eczema?

The following conditions increase the risk of developing nummular eczema:

• Cold and dry climate.
• Swelling or poor blood flow to the legs.
• History of any type of eczema.
• Skin injury, such as an insect bite or abrasion.
• Recent surgery.
• Certain medications.
• Chronic venous insufficiency and advanced age are recognized risk factors, particularly when lesions occur on the lower legs.

What Are the Symptoms of Nummular Eczema?

• Coin-shaped lesion on any body part.
• Appears in extremities but may spread to the chest and hands.
• Tiny nodules and blister-like lesions may appear first, especially after skin injury. These nodules crust over and join together, forming round to oval plaques.
• In darker skin tones, the spots may appear brown or hyperpigmented, while in lighter skin tones, they are pink or red.
• Raised scaling of the scratched areas can last for weeks to months.
• Itchy, with scratching becoming worse at night or when an individual is resting.
• Dryness occurs; therefore, scratching causes openings in the skin, leading to possible infection.
• New lesions may appear as older ones fade.
• In severe flare-ups, large, raised patches may develop instead of classic coin-shaped spots.

How Is Nummular Eczema Diagnosed?

Nummular eczema is diagnosed through:

• A complete medical history.
• Clinical examination of the skin.
• A superficial skin scraping to rule out fungal infection if necessary.
• An allergy test is performed when an external allergic reaction is suspected.
• Skin biopsies are seldom done, but may be done when the diagnosis isn’t clear.

How Is Nummular Eczema Treated?

Symptoms can be managed with medications and lifestyle changes, which may also reduce the chance of flare-ups.

Medications:

• Topical corticosteroids are used to decrease inflammation.
• Tacrolimus ointment, Pimecrolimus cream, or tar products are also available.
• For moderate to severe cases, higher-dose oral or intralesional medications may be required for a short time; in addition, using wet bandages (wet wrap therapy) on the affected area may help improve healing time.
• Antihistamines may help with itching, especially at night.
• If a secondary bacterial infection is present, then antibiotics such as Erythromycin and Flucloxacillin would be prescribed.
• Phototherapy (ultraviolet light therapy) would be indicated for either widespread areas of nummular eczema or patients with an unresponsive case.
• Keeping the skin moisturised daily, especially after bathing, is important.
• Severe or unresponsive cases may require Methotrexate, Azathioprine, or Cyclosporine.
• Using oral corticosteroids for short periods of time for recurrent disease is not usually the method of choice for ongoing management because of the potential to relapse once the medication has been stopped.
• The use of the most recent approved systemic medications (biologics, such as Dupilumab, and JAK inhibitors) should be reserved for patients with severe, unresponsive nummular eczema and after a specialist evaluation.

Lifestyle Changes:

• There is no permanent cure for nummular eczema, but lifestyle modifications help reduce flare-ups.
• Avoid irritants like wool, harsh household cleaners, and chemicals.
• Limit long, hot showers and avoid harsh soaps.
• Manage stress effectively.
• Use fragrance-free laundry products.
• Avoid activities that scrape or injure the skin.
• Apply thick moisturizers at least twice daily, particularly during winter.

Diet:

• A balanced, nutrient-rich diet and maintaining a healthy weight are beneficial.

Foods to Eat Include:

• Fish are rich in omega-3 fatty acids.
• Flaxseeds, walnuts, and leafy greens.
• Olive oil and canola oil.
• Fruits, vegetables, and whole grains.
• Turmeric and ginger.

Foods to Limit Include:

• Trans fats and fried foods.
• Excess saturated fats.
• Refined sugars and highly processed foods.
• Dietary changes alone do not treat nummular eczema unless a confirmed food allergy exists.

What Should Individuals Expect?

With proper diagnosis, self-care, and treatment, nummular eczema usually improves within several weeks. The lesions flatten, lighten in the center, and gradually resolve. However, recurrence is common.

How to Prevent Nummular Eczema?

• Take lukewarm showers for no more than 15 to 20 minutes.
• Apply fragrance-free moisturizers immediately after bathing.
• Use mild, non-irritating skin care products.
• Use a humidifier in dry indoor air.
• Protect the skin from injuries and harsh chemicals.
• Wear cotton gloves under waterproof gloves when needed.
• Reduce stress through yoga or meditation.
• Avoid overheating and excessive sweating.
• Wear loose-fitting, breathable clothing.
• Avoid rough fabrics like wool.
• Limit alcohol intake.
• Early treatment of small lesions may prevent widespread flare-ups.

What Conditions Should Be Considered in the Differential Diagnosis?

• Tinea corporis.
• Plaque psoriasis.
• Pityriasis rosea.
• Contact dermatitis and cutaneous lymphoma may rarely mimic nummular eczema and require specialist evaluation.

What Is the Prognosis?

The prognosis is generally good. With appropriate treatment, many cases improve within one year. However, this is a chronic condition with the potential for recurrence. Lesions on the legs and feet may take longer to heal and can leave residual pigmentation changes.

Conclusion

Nummular eczema is a chronic inflammatory condition that produces itchy, coin-shaped plaques that may ooze or crust. Though annoying and persistent, symptoms can be alleviated with a timely diagnosis, appropriate medication, regular moisturization, and lifestyle modifications. Prevention through trigger avoidance and long-term skin care will help keep symptoms from returning. For any queries regarding skin issues, you can talk to a skin care specialist for proper guidance.

Key Takeaways

• Nummular, or "coin-shaped," eczema will usually cause itchy patches of skin that can be wet, crusty, or bumpy.
• Although nummular eczema is not contagious, it often occurs repeatedly, which can be driven by weather or seasonal changes (e.g., dry or cold conditions).
• With proper care (regular moisturization and avoidance of triggers), these patches of skin can typically be kept under control.