Not changing underwear for a long time may cause skin infection, skin eczema and other diseases. 1. Skin infections: long-term not changing underwear, do not pay attention to personal hygiene, due to local sweat urine and other secretions stimulation, may cause perineal skin folliculitis, or skin boils and other diseases, may breed fungal infections, caused by jock itch, as well as men’s circumcision and glans dermatitis and other diseases. 2. Skin eczema: long-term not changing underwear will cause skin cleaning is not in place, may induce scrotal eczema, vulvar eczema and other diseases caused by skin redness, blisters, itching, oozing and other symptoms. You should understand the dangers of not changing your underwear for a long time, avoid these bad habits, the symptoms of discomfort, timely medical treatment as prescribed by the doctor.