There is a hard layer of skin on the foreskin, common causes include glansitis, warts, prepuce, etc., need to go to the hospital in time to find out the cause of the disease. 1. glans: glans is the inflammation of the head of the penis or the foreskin of the penis caused by various factors such as infection, the foreskin of the penis is warm and moist, may host a large number of microorganisms, when there is an infection, it can lead to the foreskin of the penis, edema, erythema, pain and other symptoms. 2. Warts: Warts are sexually transmitted diseases caused by the human papilloma virus. The location, size and shape of warts vary, and when the human body is infected with the genitals and anus around the appearance of varying sizes, single or multiple lesions, the foreskin can appear a layer of hard skin. 3. Phimosis: Phimosis refers to the narrow opening of the foreskin, resulting in the phenomenon that the foreskin can not be turned up and the head of the penis can not be exposed. Because the patient’s foreskin is too long, so the foreskin will remain some foreskin scale, urine and other substances, so it looks like a layer of hard skin at the foreskin. There are many reasons why there is a hard layer of skin on the foreskin and you should go to the hospital immediately.