What is Nummular Eczema?

Nummular eczema is a dermatological condition characterized by a rash and round patches of itchy, dry skin. Typically, the initial onset of this condition is evidenced by the appearance of reddish, coin-shaped spots and fluid-filled blisters, known as papules and vesicles, respectively. Since these lesions often evolve into a ring formation with a clear center, nummular eczema is sometimes mistaken for ringworm, which is a fungal infection. While all forms of eczema are collectively referred to as atopic dermatitis, nummular eczema is known by several other names. These include discoid eczema, eczematous dermatitis, and nummular dermatitis.

While this particular type of skin disorder is distinctive in appearance from others that fall into the category of eczema, they collectively share one common trait — the cause is a mystery. However, it is known that nummular eczema is not the result of heredity, allergy, or fungal infection, nor is it contagious. Its progression between individuals may vary greatly, though. In fact, one person may suffer an outbreak of only one or two lesions for a period of just a few weeks, while others may have multiple lesions that persist for years. In addition, there is always the chance of recurrence for every patient.

Anyone of any age may develop nummular eczema, although it is most commonly seen in patients between the ages of 55 to 65 years. While it is more common in men, women may experience their first outbreak between the ages of 15 and 25 years. The lower legs are most commonly affected, an observation that has earned this condition the nickname of varicose eczema. However, this condition may also involve the torso, arms, and hands.

Since the cause of nummular eczema is unknown, there is no certain cure or path to prevention. Therefore, treatment consists of various therapies to minimize symptoms and discomfort. Itching and redness may improve with frequent moisturizing and practicing avoidance of irritants, such as very hot water, chemicals, and uncomfortable clothing. Some patients respond well to treatment with artificial ultraviolet light. However deliberate and prolonged exposure to natural sunlight is not recommended due to the risk of sunburn.

Topical or oral medications may also be used to help control nummular eczema. In cases where the lesions are “wet” (i.e., oozing), oral penicillin antibiotics may be given, such as flucloxacillin. Anti-histamines are sometimes helpful to reduce itching. In very severe cases, the patient may be given corticosteroids (i.e., prednisone) either orally or by injection for one to two weeks to get the condition under control, followed by topical treatments for continued management.