Men will be itchy after coitus is considered to be caused by allergies, bacterial and fungal or trichomonas infections and sexually transmitted diseases. 1. Allergy: If the patient uses a condom during sex, a very small number of patients may have an allergic reaction to the condom, and then the patient’s external genital area may have red spots, redness, swelling, and itching symptoms, which is considered to be caused by contact allergy. 2. Bacterial and fungal or trichomonas infections: If the woman who is having sex with the condom has bacterial vaginitis, fungal vaginitis and trichomonas vaginitis and other inflammatory diseases. The patient may be infected after the patient through sexual contact. Itching, glans redness and erythema, and may be accompanied by local pain, or patients with local white secretion increase. 3. Sexually transmitted diseases: such as gonorrhea, chlamydia and syphilis spirochete infections, patients will appear itching and local lesions, resulting in local skin ulceration, pus and ooze. If a man is itchy after intercourse, it is recommended that the patient consult a doctor in time to identify the cause of the disease and treat the cause.