Discoid, or nummular, eczema is a chronic form of dermatitis characterised by well-defined circular plaques. Associations include allergic contact dermatitis, low environmental humidity and excessive alcohol intake. It is managed by avoidance of triggers and use of emollients and topical corticosteroids.
- Discoid eczema is a sub-type of nonatopic eczema defined by circular or oval plaques of eczema with a well-demarcated edge.
- It tends to follow a chronic course.
- The four clinical variants of discoid eczema are exudative nummular eczema, dry type nummular eczema, discoid eczema of the hands and exudative discoid with lichenoid chronic eczema.
- Differential diagnoses for eczema include tinea corporis, psoriasis and pityriasis rosea and are important to rule out for optimal management.
- It is managed through conservative skin care measures, as well as use of emollients and topical corticosteroids.
- Secondary infection with Staphyloccocus species is common and requires treatment with systemic or topical antibiotics.