Nummular eczema or dermatitis, also called discoid eczema, is skin inflammation characterized by coin shaped, circular lesions on the legs, hands, arms and torso. Tiny spots and blister like sores that weep fluid enlarge and grow together to form the circular patches. The pink, red, or brown well defined patches range in size from one to four inches in diameter. The patches can itch and burn and be very painful. Blisters may appear and after they break open they can become crusty and then scaly. Sometimes a staph infection may occur which is indicated by a yellowish crust on the patch. This type of infection would require an antibiotic. Nummular eczema is not contagious.
Nummular dermatitis is most commonly found in men between 55 and 65 years of age but is also found in women between the ages of 15 and 25 years. It is not common in children. It occurs most frequently in people that:
- Have severely dry skin
- Live in a dry environment
- Take frequent hot baths or showers
- Have other types of eczema such as atopic or stasis dermatitis
- Have poor blood circulation or swelling in the legs
- Have a bacterial skin infection
- Have a skin injury caused by a bug bite, chemical reaction, or abrasion
- Take certain medicines, such as isotretinoin and interferon
- Are sensitive to metals, including nickel and mercury (such as from a dental filling), Formaldehyde, or medicines such as neomycin (topical antibiotic)
Nummular dermatitis is diagnosed by a dermatologist who would do a visual inspection of the skin. If there are sores at the time, the doctor may want to swab the sore to test for a skin infection. If the dermatologist thinks that you may have an allergy, he or she may recommend patch testing, which is a skin test to detect allergies.
Treating this form of dermatitis can be challenging since the sores have a tendency to be stubborn. See your dermatologist and follow these recommendations to avoid a serious case of nummular dermatitis:
- Avoid skin injuries.
- Keep your skin well hydrated. Take a lukewarm daily shower lasting no longer than 20 minutes and immediately apply a moisturizer such as Vanicream to the damp skin.
- Follow your dermatologists’ orders and take any prescriptions as directed. A corticosteroid ointment may be prescribed which would help reduce inflammation and itch.
- Antihistamines can be taken at night to reduce itch and help you to sleep.
If your condition worsens and spreads you may need to:
- Sleep or rest in a cool moist room and use a humidifier if needed
- Take an oral antibiotic if a bacterial or staph infection develops
- Use medicated wound dressings
- Phototherapy (treat the wounds using light)
- Regular use of corticosteroids by mouth or injection
With proper care and treatment the nummular dermatitis can clear completely although sores on the thighs, legs and feet take longer to heal. Some patients’ skin will clear within a year while others may have the patches for several years. Occasionally the patches will reappear in the spot they originated in.