Erythromycin is not useful for vulvar itching. The reason is that vulvar itching is overwhelmingly due to local allergic reactions that cause itching symptoms. For example, dermatitis of the vulva, which has red papule-like changes, requires dermaplanin or mometasone ointment to be applied to the area to stop the itching. In addition, candida vaginitis and trichomonas vaginitis, the inflammation caused by these two bacterial infections, in addition to local redness, swelling, heat and pain, can lead to allergic reactions, which can cause itching of the vulva. Therefore, medication should be used according to the cause of vulvar itching in order to achieve the desired effect. For example, candida infection can be treated by plugging clotrimazole pessary; if it is trichomonas infection vagina can be treated by plugging metronidazole pessary.