Last updated: March 2024
Also known as: Discoid Dermatitis, Nummular Dermatitis, Nummular Eczema, Microbial Eczema
What is discoid eczema?
Discoid eczema is a common type of eczema or dermatitis with coin-shaped areas of inflammation on the limbs or torso. It is usually very itchy.
Who gets discoid eczema?
Discoid eczema can affect individuals across all age groups. It tends to be more prevalent among older adult males and younger adult females.
Drug-induced discoid eczema may also arise from medications that induce skin dryness.
What causes discoid eczema?
The cause of discoid eczema is unknown.
Some individuals have conditions related to eczema such as hay fever or asthma. Dry skin may aggravate or predispose an individual to developing discoid eczema and the rash may be worse in winter. Less commonly, certain medications, or contact with a chemical in the individual’s environment, may play a role.
What does discoid eczema look like?
Initially, the coin-shaped areas may be pink and relatively flat with some scaling, but other changes may occur such as thickening of the skin, oozing, crusting and severe itch. As the rash improves, some brownish or pale discolouration may occur which gradually disappears over months.
In some cases, the rash may become more widespread. Secondary infection may occur with significant oozing of fluid and crusting.
How is discoid eczema diagnosed?
Discoid eczema is usually diagnosed clinically, based on an individual’s medical history and by examining the skin.
In some cases, a skin biopsy may be needed to confirm the diagnosis. Other tests may include:
- A swab to determine if a bacterial or viral infection is present.
- Patch testing if an individual has been in contact with a material that may be causing the condition.
How is discoid eczema treated?
Treatment options will vary depending on the individual and their needs.
General measures include:
- Wearing cotton clothing
- Avoiding overheating
- Avoiding irritating products
- Avoiding allergens
- Using soap substitutes such as sorbolene and glycerine
- Using moisturisers at least after bathing, such as sorbolene and glycerine
Specific treatments may include:
- Oral antibiotics
- Topical steroid (anti–inflammatory) ointments or creams
- Antihistamines
If discoid eczema becomes more chronic, or does not respond well to these measures, other treatment options will be discussed. Other treatment options may include local intralesional steroid injections, phototherapy, oral immunosuppression (i.e., Methotrexate, Cyclosporine or Azathioprine), and in some cases, biologic medications (i.e., Dupilumab).
What is the likely outcome of discoid eczema?
Discoid eczema typically presents as a chronic condition with frequent relapses, particularly during the winter months. In most cases the condition improves, but it may take longer to respond to treatment than other types of eczema.
| Dr Sara Tritton | March 2024 |
| Dr Sara Tritton | July 2015 |