Itchy perineum at night during the day is fine, can be caused by mycosis vaginalis, eczema, folliculitis, etc., this time you can follow the doctor’s instructions to use the appropriate drugs for treatment. 1. mycosis vaginalis: can be manifested at night, before and after menstruation significantly aggravated itching, mainly due to mycobacterial infections, can be used under the guidance of the doctor clotrimazole and other drugs for treatment, in addition to pay attention to local hygiene and so on. 2. Eczema: localized vulvar eczema can also show no symptoms during the day and obvious itching at night, can be avoided by contact with poor quality sanitary napkins and other suspected allergens, wear breathable underwear, avoid scratching and other general treatment, you can also use drugs such as loratadine. 3. Folliculitis: folliculitis in perineum area is also easy to cause itching, during the daytime can be busy due to work without paying attention to the local symptoms, at night in a quiet state can feel itchy obviously, in addition to the above general treatment, but also can be localized to use erythromycin ointment for treatment. It is recommended to go to the hospital in time to avoid delaying the condition.