Because some doctors only pay attention to the genital area skin damage manifested by STDs, and ignore that other diseases can also lead to the same symptoms, the result is blindly and rashly misdiagnosed as STDs that are not STDs, causing unnecessary pain and mental stress to patients. In fact, the genital area of many skin damage, a large part does not belong to the STD, the two must not be confused, now these easily confused with STD disease is introduced as follows, in order to draw attention to. Allergic diseases: allergy after taking drugs can cause glans foreskin fixed drug rash; drug or food allergy can also cause serious foreskin edema; contact dermatitis caused by contact with topical drugs, contraceptive tools or diapers, such as local erythema, papules, blisters, vesicles or ulcers; individual women allergic to semen can occur vaginal itching or vulvar urticaria. Second, traumatic diseases: bruises and hematomas occur during sexual intercourse; temporary obstruction of lymphatic vessels after sexual intercourse can cause cartilage-like hard cords to appear on the back of the penis or in the coronary sulcus, which can disappear on its own within a few weeks, and this condition is penile sclerosing lymphangitis; prolonged sexual intercourse can cause genital edema; foreskin flip can not be reset, which can cause severe edema of the foreskin and the end of the penis, called embedded prepuce; insect bites can also cause Redness and blisters in the genital area. Non-STD infections: When the lower part of the genitalia is parasitized by the coarse bacillus, it can cause acute feminine ulcers; 2-3 days after sexual intercourse, it can also cause erosive foreskin glansitis due to the infection of circumcision bacillus or enderson pressure spirochetes or clostridium. Pre-cancerous diseases and malignant tumors: White spots and hypertrophic erythema occurring on the genital area, especially those showing keratinized roughness, desquamation, warty proliferation and stubborn ulcers, may be pre-cancerous diseases or malignant tumors. V. Benign tumors or superfluous organisms: genital areas also commonly see some slow developing and persistent rashes or nodules with black, yellow, red or skin color. The lesions may be pearly penile papulosis, milia, nevus nigricans, epidermal nevus, superficial lipoma-like nevus, cutaneous endometriosis, vestibular gland cysts, sebaceous cysts, multiple lipid sacs, lipomas, raw papillary sweat adenomas, hemangiomas, smooth muscle tumors, fibromas, or cutaneous lymphocytomas. Sixth, other diseases: There are also some diseases with complex causes or unknown etiology so far, which can also lead to genital area or systemic lesions, such as penile cavernous sclerosis, plasma cell glans, occlusive dry glans, mica and keratotic pseudoepithelioma glans, female pubic atrophy, penile dryness, sclerosing atrophic moss, lichen planus, eczema, seborrheic dermatitis, neurodermatitis, psoriasis, and pemphigus, etc. In addition, sexually transmitted damage can be easily confused with general skin diseases and should also be distinguished.