Nummular dermatitis

Nummular dermatitis typically arises after a skin injury such as an abrasion, burn or insect bite. There might be one or several patches that can last for weeks or months.

It is important to note that nummular dermatitis typically affects women. Men usually have their initial outbreak between ages 55-65. Women develop the condition at a younger age, usually in the teenage year or as young adults.

Indications of nummular dermatitis

The skin patches tend to start as a group of reddish, small spots and blister-like sores that drain fluid. The sores grow bigger and together to form as a coin-shaped patch. These patches tend to have these indications:

  • Vary in size from 1-4 inches
  • Usually develop on the legs but also on the torso, hands, arms and feet
  • Reddish, pinkish or brownish in color and well-defined
  • Itchiness and burning sensation from mild to severe.
    Nummular dermatitis

    Usually develop on the legs but also on the torso, hands, arms and feet.

  • Become crusted after the blisters drain fluid

What are the causes?

Even though the cause is unknown, it is believed that sensitivity has a role in some cases. An individual might be sensitive to:

  • Formaldehyde
  • Metals such as nickel
  • Medications such as neomycin

If the individual has sensitivity, the skin will only clear up when the individual avoids the substance. The risk for developing nummular dermatitis is increased among those who live in dry, cold climates or have the following:

  • Excessive skin dryness or xerosis
  • Having another form of eczema such as stasis or atopic dermatitis
  • Poor flow of blood and/or swollen legs
  • Skin infection due to bacteria
  • Skin injuries such as an abrasion, insect bite or exposure to chemicals
  • Certain medications such as interferon and isotretinoin


The sores caused by nummular dermatitis can be persistent. It is recommended to consult a doctor for proper treatment which usually includes the following:

  • Protecting the skin from injuries since it can worsen nummular dermatitis.
  • Ensure proper hydration of the skin. This can be done by taking a 20-minute lukewarm shower or bath once a day. After getting out of the water, apply a moisturizer on the damp skin. This can keep dry skin hydrated as well as alleviate the itchiness and scaling.
  • Medications might be prescribed by the doctor such as tar creams and corticosteroid ointments. These medications work by reducing the inflammation and itchiness.