Small bumps on the skin of the penis may be caused by folliculitis, penile pearly rash, warts and so on. 1. Folliculitis: If you usually do not pay attention to personal hygiene or hair follicle blockage caused by sebaceous gland infection, most of them are caused by Aureobasidium infection, appearing small bumps on the penis skin, and accompanied by itching, redness, swelling, pain and other symptoms. 2. Penile Pearl Rash: Pearly penile papules is a skin disease characterized by the appearance of pearly, translucent papules on the coronal edge and coronal groove of the penis. It manifests itself as a circle of small bumps on the penile skin, which may be related to long foreskin, poor personal hygiene, local irritation and so on. 3. acromegaly: acromegaly is caused by human papillomavirus infection, belonging to the sexually transmitted diseases, can be manifested in the penis, glans and other parts of the cauliflower pattern, lobular warts, similar in appearance to small bumps, can be increased in a short period of time, increase. When men have small bumps on the skin of the penis, they should go to the hospital immediately to find out the cause of the disease, and then under the guidance of the doctor, so as not to delay the condition.