Penile skin loss and redness may be due to syphilis and penile eczema. The causes vary from disease to disease. 1. Syphilis: a group of diseases mainly transmitted through sexual contact, vertical transmission and other indirect sexual contact. The mucopolysaccharide enzyme on the surface of the syphilis spirochete has a high affinity for mucopolysaccharide-rich tissues such as skin and aorta. It is divided into three phases, the first phase is mainly the external genital noma, the second phase is syphilis rash, flat warts on the vulva, and the third phase will appear syphilitic gumbo. 2. Penile eczema: penile eczema is an inflammation of the superficial dermis and epidermis caused by a variety of internal and external factors. Internal factors are related to chronic infectious lesions, endocrine and metabolic changes, and blood circulation disorders. External factors are associated with food, inhalants, and environmental factors, and a few are mediated by delayed hypersensitivity reactions. Pinpoint, corn-like sized papules may appear on the penis. If you experience penile skin loss and redness, you need to seek medical attention as soon as possible to avoid delays.