The redness, swelling and itching of the foreskin are usually caused by diseases such as glans phimosis, genital herpes and dermatitis. 1. glans penis: is caused by pathogen infection, external stimulation and other factors of the glans, foreskin inflammation, patients will appear red, swelling, burning pain, itching and other discomforts, and can be seen in the glans localized skin mucous membrane erythema or vesiculitis, in severe cases, but also fever, inguinal lymph nodes swollen and other symptoms. 2. Genital herpes: a contagious disease caused by herpes simplex virus infection, male patients, the foreskin, glans, coronal groove, anus and other parts of the scalp, blisters, ulcers and other lesions, and can be accompanied by a strange itch, part of the patient’s foreskin will be red, edema oozing and so on. 3. Dermatitis: the causes are complex and varied, when the foreskin comes into contact with allergens (such as condoms, detergents, etc.), it is easy to trigger dermatitis, resulting in erythema, edema, pimples or ulceration of the foreskin, and can be accompanied by itching, pain and other discomforts. In addition, there are many other causes can cause redness and itching of the foreskin, it is recommended that the patient to the hospital in time to identify the cause of the disease, and receive treatment as soon as possible.