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Discoid eczema

What is discoid eczema?

Discoid eczema is a common type of eczema/dermatitis defined by scattered, well-defined, coin-shaped and coin-sized plaques of eczema. Discoid eczema is also called nummular dermatitis.

Discoid eczema 

Discoid eczema 

What is the cause of discoid eczema?

The cause of discoid eczema is unknown. Some cases are associated with Staphylococcus aureus infection.

The eruption can be precipitated by:

• A localised injury such as scratch, insect bite or thermal burn
• Impetigo or wound infection
• Contact dermatitis
• Dry skin
• Varicose veins (varicose eczema).

Who gets discoid eczema?

Discoid eczema can affect all age groups. It is slightly more common in older adult males and younger adult females. In males there is an association with chronic alcoholism. Drug-induced discoid eczema can be due to medications that cause skin dryness.

What are the clinical features of discoid eczema?

Discoid eczema usually affects the limbs, particularly the legs, but the rash may be widespread. Although often bilateral, the distribution can be asymmetrical especially if related to varicose veins.

There are two clinical forms of discoid eczema:

• Exudative acute discoid eczema: oozy papules, blisters, and plaques
• Dry discoid eczema: subacute or chronic erythematous, dry plaques

Individual plaques are well-circumscribed, mostly 1–3 cm in diameter, and inflamed. The majority of patches are round or oval. The plaques are usually very itchy. The skin between the patches is usually dry and irritable.

Severe discoid eczema may generalise, with numerous small to large itchy plaques appearing all over the body due to an autoeczematisation reaction.

Patches may clear up without leaving a sign. In dark skin, marks may persist for months as dark brown postinflammatory hyperpigmentation or pale postinflammatory hypopigmentation.

Read more about discoid eczema.

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