In later life both sexes are affected equally. A familial tendency to develop this condition has been noted. Lesions may, however, measure up to 10 mm in diameter. They are often noted first on the anterior legs. Later, they appear on the forearms.
Distribution seems photorelated except for face, which is affected later than the limbs.
This condition should be diagnosed on clinical grounds. In atypical cases a biopsy may be indicated. Wood s light examination could be helpful in revealing unsuspected involvement. Dopa staining can be useful because dopa-positive melanocytes are decreased. Typical histologic findings are epidermal atrophy, patchy absence of melanocytes and melanin, flat rete ridges, and basket weave hyperkeratosis.