A lump on one side of the vulva that is painless and itchy may be caused by vestibular cysts, warts, syphilis infection and vulvar fibroma. 1. Vestibular cysts: a lump on one side of the vulva that doesn’t hurt or itch may be caused by a vestibular cyst. There is a vestibular gland on both sides of the labia majora, and if the gland ducts are clogged with secretions, a cyst will form, and when the cysts are small and there is no infection, the patient will have no symptoms. 2. Condyloma acuminatum: a lump on one side of the vulva is painless and itchy. If the lump protrudes from the skin surface, it is usually considered to be condyloma acuminatum caused by infection with the human papilloma virus. 3. Syphilis infection: when the chancre appears after syphilis infection, there will be lumps on the vulva and it is painless and itchy. 4. Vulvar fibroma: It is a benign tumor of the vulva caused by the proliferation of fibrous tissue in the vulva. It is a benign tumor of the vulva, manifested as a brown hard lump, usually painless and itchy. Therefore, the lump on one side of the vulva without pain or itching may be caused by vulvar fibroma. When the patient has the symptom of lump on one side of the vulva without pain or itching, he should go to the hospital in time to do the relevant examination and reasonable treatment under the guidance of the doctor.