Nummular eczema (also known as discoid eczema and nummular dermatitis) is a common type of eczema that can occur at any age. It is notable because it looks very different than the usual atopic dermatitis and can be much more difficult to treat.
The word “nummular” comes from the Latin word for “coin” as the spots can look coin-shaped on the skin. They tend to be well-defined, but may be very itchy or not itchy at all. They can be very dry and scaly or can become wet and open.
The cause of nummular eczema is unknown, but it tends to be more isolated than atopic dermatitis and does not seem to run in families. Sometimes there is a triggering event such as:
Because it can look like ringworm (tinea corporis), it is important to make sure that it is not a fungal infection, especially if it is not responding to treatment. This can usually be done with a scraping or a fungal culture. Like atopic dermatitis, nummular eczema can also become infected by bacteria—usually staphylococcus—and should be treated as well if present.
Like atopic dermatitis, nummular eczema benefits from moisturizers to calm and protect the damaged skin barrier.
In many cases, you may receive a prescription for a corticosteroid medication to calm the inflammation as well. For some reason, the milder and even more moderate-potency corticosteroid creams may not be of much help with nummular eczema; more powerful creams are frequently required. Fortunately, unlike the chronic nature of atopic dermatitis, nummular eczema tends to disappear completely after adequate treatment in many individuals, minimizing the chance for side-effects with these stronger topical corticosteroids.
In cases where corticosteroids are not appropriate, or when they have been used for a prolonged period, a non-corticosteroid topical medication such as tacrolimus (Protopic) or pimecrolimus (Elidel) may be prescribed. These agents, topical calcineurin inhibitors , are approved for use by adults and children two years of age or older, and they avoid many of the side effects of corticosteroids.
Topical or oral antibiotics may be used when there is evidence of bacterial infection.
Oral antihistamines can be helpful for some, and may reduce some of the itch, especially at night.
In very severe cases, systemic steroids may be used for a short time. Again, unlike atopic dermatitis, there seems to be less risk of a “rebound flare up”, and so these can be used more safely for this condition when needed.
Although nummular eczema may be a form of atopic dermatitis, it appears to be a more limited one. Many individuals, even those presenting with very severe disease, seem to clear up completely after a short time and do not appear to have the long-term issues like other forms of eczema.
View more nummular eczema pictures at skinsight.com.