Nummular dermatitis

Alternative names
Eczema - nummular; Nummular eczema

Definition
Nummular eczema is an allergy-related skin disorder causing characteristic itchy, coin-shaped lesions.

Causes, incidence, and risk factors
The cause of nummular eczema is unknown, but there usually is a personal or family history of asthma, allergies, atopic dermatitis, or similar disorders. It is a relatively uncommon disorder that most often occurs in elderly men.

Eczema is generally a chronic, recurring condition. Exposure to environmental irritants may worsen symptoms, as can dryness of the skin, temperature changes, and stress.

Symptoms

     
  • Itching  
  • Skin lesions that may be macules, papules, vesicles, or patches       o Nummular (coin shaped)       o Primarily located on the arms and legs       o Spreading to the trunk       o Oozing, crusting over  
  • Scaly or excoriated (raw) skin  
  • Skin redness or inflammation

Signs and tests
Nummular eczema is diagnosed based on the appearance of the skin, and on personal and family history. A skin biopsy may sometimes be needed to exclude other conditions with a similar appearance.

Treatment
The health care provider should be consulted for diagnosis of nummular eczema, as it can be difficult to differentiate from other skin disorders. Treatment should be guided by the health care provider.

Treatment is focused on relief of the symptoms. Anything that aggravates the symptoms is avoided whenever possible. Frequent bathing is not advised. Other possible allergens are avoided, including foods and environmental irritants, such as wool and lanolin.

Dry skin often makes the condition worse, so bathing and the use of soaps may be reduced. Temperature changes and stress may cause sweating and changes in the blood vessels of the skin, also aggravating the condition.

Topical treatment of weeping skin areas may include soothing lotions, soaps, or wet dressings. Mild antipruritic lotions or topical (applied to a localized area of the skin) steroids may be used to soothe scaly, dry, less acute, or healing areas. Chronic areas may be treated with ointments or creams that contain tar or corticosteroids, or lubricating, skin softening, or other ingredients. Systemic corticosteroids may (rarely) be used for severe cases.

Expectations (prognosis)
Nummular eczema is a chronic condition, but it may be controlled with treatment and avoidance of irritants.

Complications
Possible complications are secondary infections of the skin.

Calling your health care provider
Call for an appointment with your health care provider if symptoms indicate that you may have nummular eczema.

Call for an appointment with your health care provider if symptoms persist despite treatment and avoidance of allergens, or if signs of infection (such as fever, redness, or pain around a lesion) occur.

Prevention
There is no known way to prevent the disorder. Avoiding environmental irritants and other aggravating factors may reduce the severity of symptoms in people who have nummular eczema.

Johns Hopkins patient information

Last revised: December 5, 2012
by Potos A. Aagen, M.D.

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