Describe the typical presentation of nummular eczema.

Typically, patients are men 55 to 65 years old who report the rapid onset of tiny papules and juicy vesicles that form erythematous, 1- to 10-cm diameter, coin-shaped (i.e., nummular) plaques studded by pinpoint vesicles and erosions on a background of dry skin (Fig. 8-3). Plaques sometimes clear centrally and resemble tinea corporis. They are found most commonly on the extensor surfaces of the lower extremities, are often bilaterally symmetrical, may recur at sites of previous involvement, and are intensely pruritic. The upper extremities and trunk are involved less frequently. When the trunk is involved, only the back is usually affected.