Vaginal blisters are a type of genital sore that develops in the outer area of the vagina or inside the vagina. A woman might develop vaginal blisters because of a sexually transmitted disease (STD), but this isn't always the reason. In some cases, a person will develop this type of blister because of an allergy or chemical irritant, such as a soap or detergent that irritates the sensitive vaginal tissues. Some women might also develop blisters in this area because of an excessive amount of friction without a suitable amount of moisture in the area, such as when engaging in intercourse while also experiencing vaginal dryness.

Sometimes a woman develops vaginal blisters because of an STD. For example, an STD called herpes is often at fault when a woman develops a blister in the vaginal area. Such blisters can appear on a periodic basis, whenever the person has an outbreak of herpes, and can cause pain in the area — some people also experience burning and itching while the blisters are active. Herpes blisters are often filled with fluid, which usually will ooze out before the sores eventually heal. In addition to vaginal blisters, a woman with herpes might also experience fevers, develop headaches, experience swollen lymph nodes and have an abnormal vaginal discharge.

Just about any condition that results in irritation to the vagina has the potential to cause vaginal blisters. Besides STDs, this can include allergies and infections that are not typically transmitted via sex. For example, some people develop blisters in this area because of allergies to things with which they come into contact, such as soaps and scented feminine products, or underwear that has been laundered with a detergent to which the person is allergic. If a woman is allergic to latex and uses latex condoms, this could cause blistering as well. Additionally, a woman may have a non-sexually-transmitted infection caused by viruses, bacteria, or fungi that can lead to this type of blistering.

Some women also develop vaginal blisters after episodes of sexual contact. In such a case, the friction experienced during sexual activity can cause irritation, blistering, and sometimes even tearing in the area. For some women, this problem develops when sexual intercourse does not include a sufficient amount vaginal lubrication or when the activity is particularly rough. Women can also develop this type of blistering in the absence of sufficient vaginal lubrication in combination with condom use.