If clearly defined round or oval dry plaques resembling coins appear on the skin, one possible cause may be nummular eczema (discoid eczema). These lesions are typically red or pinkish-red in color and may become scaly, crusted, and intensely itchy.
The rash most commonly develops on the lower legs, arms, forearms, hands, and less frequently on the trunk. The lesions can range in size from a few millimeters to several centimeters. Because of their characteristic round shape, the condition is often mistaken for a fungal skin infection, particularly ringworm.
Nummular eczema is not contagious and cannot be transmitted to other people. The condition may follow a chronic course, with periods of improvement alternating with recurrent flare-ups. With proper treatment and skin care, symptoms can usually be effectively controlled.
What to Do If You Suspect Nummular Eczema
If round, itchy plaques appear on the skin, it is recommended to consult a dermatologist. Despite its characteristic appearance, it can be difficult to establish an accurate diagnosis based solely on photographs or visual examination.
Before seeing a doctor, it is recommended to:
- moisturize the skin regularly;
- avoid scratching the lesions;
- stop using harsh cleansing products;
- avoid prolonged contact with hot water;
- avoid using antifungal or steroid medications without a diagnosis.
It is especially important to seek medical attention if the lesions rapidly enlarge, become painful, start oozing, or appear on new areas of the body.
Self-treatment may lead to temporary symptom relief, but an incorrect diagnosis often delays proper treatment.
What Nummular Eczema Looks Like
Nummular eczema gets its name from the characteristic shape of its lesions.
The most typical features include:
- round or oval plaques;
- well-defined borders;
- red, pink, or reddish-brown coloration;
- dryness and scaling;
- small blisters during the active phase;
- crusting;
- cracks on the skin surface.
The most common locations are:
- lower legs;
- thighs;
- forearms;
- hands;
- shoulders;
- trunk.
In the early stages, the lesions may be small. Over time, they may enlarge and become more noticeable. Some people develop multiple lesions of varying sizes simultaneously.
Below in the article, you can see real photos to better understand what the condition looks like.
Main Symptoms
The most common reason patients seek medical attention is itching.
Characteristics of itching in nummular eczema include:
- it may be persistent;
- it often worsens in the evening;
- it may become more intense at night;
- it can worsen after showering or contact with water;
- it frequently leads to scratching.
Other symptoms include:
- round, itchy plaques;
- dry skin;
- scaling;
- redness;
- burning sensations;
- crust formation;
- painful fissures.
With long-standing disease, the skin within the lesions may become thicker and rougher.
Causes of the Condition
The exact cause of nummular eczema remains unclear. It is believed to develop due to impaired skin barrier function combined with increased sensitivity of the immune system.
Factors that may contribute to the condition include:
- dry skin;
- cold and dry weather;
- frequent washing;
- hot showers;
- emotional stress;
- contact with irritating substances;
- certain metals and chemical compounds;
- atopic dermatitis;
- chronic skin disorders.
Many patients experience more frequent flare-ups during autumn and winter, when the skin loses more moisture.
How the Condition Develops
Under normal conditions, the skin retains moisture and protects the body from external irritants. When this barrier becomes impaired, the skin becomes drier and more sensitive.
In response to irritating factors, inflammation develops. Areas of redness appear, forming the characteristic round lesions that may become scaly and itchy.
Scratching further damages the skin and perpetuates the inflammatory process. In long-standing cases, repeated cycles of flare-ups and remission may occur.
Conditions That Can Be Mistaken for Nummular Eczema
Nummular eczema is one of the skin conditions most frequently mistaken for a fungal infection. This is why accurate diagnosis is particularly important.
Ringworm (Tinea Corporis)
This is the most common source of diagnostic confusion. In fungal infections, lesions usually have a more active, raised border and tend to spread gradually outward. Laboratory testing may be required to confirm the diagnosis.
Fungal Skin Infection (Mycosis)
Some forms of fungal infection can cause round, scaly patches that resemble nummular eczema.
Psoriasis
Psoriasis typically produces thick plaques covered with silvery-white scales. However, on certain areas of the body, distinguishing between the two conditions can be difficult.
Contact Dermatitis
Allergic or irritant skin reactions may create round inflammatory patches that resemble eczema.
Scabies
Scabies is more commonly associated with intense nighttime itching, burrows, and lesions between the fingers, on the wrists, and in other characteristic locations.
Pityriasis Rosea
In its early stages, some forms of pityriasis rosea may resemble nummular eczema.
For this reason, it is not always possible to determine the cause of round plaques on the skin without professional evaluation.
Forms and Types
Acute Nummular Eczema
Characterized by pronounced redness, blisters, oozing, and intense itching.
Subacute Form
Inflammation becomes less active, while scaling and crust formation become more prominent.
Chronic Nummular Eczema
Lesions persist for a long time, the skin becomes drier and thicker, and fissures may develop.
When to See a Doctor
A dermatologist should be consulted if:
- round, scaly plaques appear;
- itching interferes with sleep or daily activities;
- lesions enlarge over time;
- new lesions appear;
- oozing develops;
- signs of infection occur;
- home skin care measures do not lead to improvement.
Early diagnosis helps rule out fungal infections and allows appropriate treatment to be started sooner.
Treatment
Treatment of nummular eczema focuses on reducing inflammation, relieving itching, and restoring the skin barrier.
A doctor may recommend:
- regular use of moisturizers;
- avoidance of irritating factors;
- gentle skin care;
- topical treatment with creams or ointments;
- management of associated skin conditions.
Additional treatment options may be required in more severe cases.
Daily skin care plays a particularly important role. Maintaining adequate skin hydration helps reduce the frequency of flare-ups and improves overall skin health.
Questions and Answers
Is nummular eczema contagious?
No. The condition is not caused by an infection and cannot be transmitted to other people.
Why do the lesions look like coins?
The inflammation spreads relatively evenly from the center of the lesion, creating its characteristic round or oval shape.
Can nummular eczema be completely cured?
Many people achieve excellent symptom control. However, the tendency toward recurrent flare-ups may persist for a long time.
Why do round dry patches appear on the legs?
One possible cause is nummular eczema. However, similar lesions may also occur with fungal infections, psoriasis, and other skin disorders.
Is nummular eczema a fungal infection?
No. It is an inflammatory skin condition unrelated to fungal infection. However, it often resembles ringworm in appearance.
Can nummular eczema itch at night?
Yes. Many patients report that itching becomes worse in the evening and during the night.
Is fungal testing necessary?
In some cases, a doctor may recommend skin testing to rule out fungal infection, especially if the appearance of the lesions is uncertain.
Will nummular eczema leave scars?
Scarring is uncommon. After healing, temporary changes in skin pigmentation may sometimes remain.
Medical Literature and Authoritative Sources
- American Academy of Dermatology (AAD)
- National Eczema Association (NEA)
- European Academy of Dermatology and Venereology (EADV)
- Fitzpatrick’s Dermatology, 9th Edition
- Andrews’ Diseases of the Skin: Clinical Dermatology
- British Association of Dermatologists (BAD)
- National Health Service (NHS)
- UpToDate: Nummular Dermatitis (Nummular Eczema)
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