Nummular dermatitis is a form of dermatitis characterized by coin-shaped, scaly plaques. While generally a disease of adults, the peak age of childhood nummular dermatitis is 5 years. It is of uncertain etiology, but it is associated with triggers such as frequent bathing, low humidity, irritating and drying soaps, and exposure to irritating fabrics such as wool. Patients often have some of the signs and symptoms typically associated with atopic dermatitis. Pruritus can be severe, and affected children can be irritable.

Winter is usually the time of onset and exacerbation. Nummular dermatitis can be chronic with a waxing and waning course.

Exudative discoid and lichenoid chronic dermatitis, also known as "oid-oid" disease and Sulzberger-Garbe syndrome, is a variant of nummular dermatitis marked by severe pruritus, chronicity, and persistence despite topical therapy. Most cases are reported to occur in adults, but cases in children are also reported.