The common clinical causes of erythema on the vulva include allergy and infection. 1. Allergy: this condition is usually related to the contact of allergic substances with the vulva skin, such as the use of certain drugs, contact with special materials of underwear or sanitary napkins, etc., which may cause local skin allergy symptoms, clinically manifested as erythema and itching of the skin. 2. Infection: If the affected area is congested and there is no obvious lesion or nodule, it is usually considered to be caused by infection of the vulva. In addition to erythema, there will be itching, abnormal secretion and change of smell. People with the disease should choose the appropriate method of treatment according to their own situation, if the erythema further aggravates, it is necessary to go to the hospital as soon as possible for a clear diagnosis, and give targeted treatment.