Small groups or isolated papules may develop on other parts of the body. Papules sometimes are more easily felt than seen. Palmar skin may be thickened and may show punctate keratosis or punctiform breaks in dermatoglyphics identical to those observed in Darier and Grover diseases. In 1947, Neidelman published the largest series. In 1962, the follow-up series by Neidelman and McKusick described 24 cases in 4 generations in the same family.
Skin biopsy is needed to establish the diagnosis.
Sections reveal hyperkeratosis, regular acanthosis, and papillomatosis which imparts a regular, undulating appearance to the surface. These changes have been likened to church spires. There is no parakeratosis, no epidermal vacuolation, and little dermal inflammatory infiltrate. Darier disease is the most important differential diagnosis and patients may show identical findings on clinical examination. Dyskeratotic cells are characteristic of Darier disease but are not present on histological examination of acrokeratosis verruciformis.