A 16-year-old girl initially had an eruption consisting of dark gray, flat, pin-sized, confluent papules with a slight hyperkeratotic surface. The lesions appeared after her summer holidays and were restricted to the tanned skin of sun-exposed areas, mainly the abdomen and back. Clinical and histologic findings were consistent with confluent and reticulated papillomatosis. If a basic disorder of keratinization is the cause of confluent and reticulated papillomatosis, it seems likely that the development of the disease in our patient may be due to an abnormal epidermal response to ultraviolet light.