What is it about ?
Nummular eczema is a chronic variant of eczema that is frequently encountered. Its name comes from the Latin “nummus”, which means currency. The lesions of the skin have the rounded shape of a coin. It is also called discoid eczema. Eczema being a skin disease, it is also called nummular dermatitis. It is not an infectious disease.
The origin is not well known. Heredity and predisposition to dry skin or allergic conditions certainly play a role. The occurrence of nummular eczema also seems to depend on a number of external factors, such as using too much or too strong soaps, stress, coarse clothing, excessive sweating, and smoke.
Where does it occur?
In adults, nummular eczema is found mainly in people between the ages of 40 and 60 and more frequently in men than in women.
How to recognize it?
Nummular eczema often begins with a single blister or spot around which several new, similar lesions appear. These cluster together to form well-defined patches, round or oval, often red, scaly, sometimes moist and itchy. Lesions can occur all over the body. Most often it starts on one leg and then extends to both sides. The other typical places are the thighs, back and arms. The elbows and the hollow of the knees are the areas most often affected.
Nummular eczema often worsens during the winter months as the air is drier, and then improves in the summer with the sun. It is a chronic disease that evolves in flare-ups and therefore keeps coming back.
How is the diagnosis made?
Usually, the doctor makes the diagnosis on the basis of the symptoms and the appearance of the lesions. Some skin conditions are very similar to nummular eczema, for example other forms of eczema, ringworm (skin fungus), the psoriasis, the’contact allergy or theimpetigo.
If in doubt, the doctor may take a sample of the skin (skin biopsy) for examination under a microscope. However, this examination has little influence on the treatment. Sometimes the doctor decides to culture a sample of fluid or pus to look for fungi. If the eczema persists and the treatments are not effective, the doctor will refer you to a skin doctor (dermatologist) to check for an allergy.
What can you do ?
The skin is naturally covered with an oily protective layer. In eczema, this layer does not form well, which causes the skin to dry out more quickly. Dry skin will itch faster. This can be avoided by applying a fatty cream every day. Bath oil can give the same result. Do not use too much soap or too much bath foam. Do not wash your skin with soap every day (except armpits and groin folds). A simple shower is enough. Avoid very hot showers of more than 5 minutes.
Use gloves if you are handling irritants.
Avoid clothing that irritates, rubs, or itches. Wear several layers of light clothing (T-shirt, then shirt, then sweater, then coat) so that you can easily remove a layer if you are sweating. Avoid extreme heat, ensure good room ventilation during the day and do not smoke in the house!
Allergy can make eczema worse. Therefore, avoid anything that can trigger this allergy. If you notice that certain foods make your eczema worse, ask for your allergies to be checked.
In children, it may be helpful to keep an eczema diary. Write down everything that may relate to eczema: flare-ups, severity of itching, location, triggering factors, effect of treatment …
What can the doctor do?
Since nummular eczema usually goes away when the skin is well cared for, your doctor will advise you to take care of your skin first. For difficult places, he may prescribe cortisone ointment and, in case of severe itching, itching medication.
In the event of persistent eczema, the doctor will refer you to a dermatologist to rule out contact allergy (allergic reaction to substances after contact with the skin). The dermatologist may also recommend ultraviolet light therapy (UVB).
Want to know more?
- Nummular eczema (image) – DermIS – Dermatology Information System
- UVB therapy, here, Where to find on this page of Cliniques St Luc UCL
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