Black spots on the calves, consider with sun exposure, seborrheic keratosis, ichthyosis and other factors. 1. Sunlight irradiation: Due to work, you are outdoors for a long time and do not pay attention to sun protection of your legs. Being exposed to ultraviolet rays may lead to melanin precipitation in the skin, and black patches may appear on the lower legs. 2. Seborrheic keratosis: Due to skin aging, abnormal skin growth and keratinization may easily occur, resulting in the appearance of black patches on the calves. 3. Ichthyosis: black patches appear on the calves, but also to understand whether it is related to ichthyosis. Because some patients with ichthyosis, will be manifested in the phenomenon of increased melanin on the calves. There may be other reasons to cause black spots on the calves, it is recommended to go to the hospital in time, clear diagnosis, symptomatic treatment.