The labia minora are the two folds of smooth, pigmented skin that lie within the larger labia majora and protect the entrance to the vagina. They are also a common site for the genital herpes lesions that, according to the Centers for Disease Control and Prevention (CDC), affect approximately one in five adult women in the United States. Herpes symptoms on the labia minora can be difficult to distinguish from those produced by other kinds of infections, therefore culture and/or antigen testing for the herpes simplex virus is required for definitive diagnosis.
The characteristic lesion of herpes, according to Cernik, Gallina and Brodell's 2008 report in the “Archives of Internal Medicine,” is a painful 1 to 2 mm bump or blister with a central depression or dimple. Blisters on the labia minora often develop in clusters and rupture spontaneously, releasing clear or cloudy straw-colored fluid that is highly infectious. Blisters may be distributed on one or both sides of the labia minora. Blisters that occur on both sides are sometimes referred to as “kissing lesions."
Women often fail to recognize ulcers as a symptom of genital herpes. The ulcer that appears on the labia minora and other parts of the female external genitalia is commonly described as a “punched-out” lesion, according to Dr. Lawrence Corey in “Harrison’s Principles of Internal Medicine,” because of its well-defined borders. Ulcers are usually larger than blisters and appear as uniform, shallow, dark pink or red erosions which make urination extremely painful.
Some blisters and ulcers develop crusts three to four days after they appear, according to Cernik and colleagues' 2008 article in the “Archives of Internal Medicine.” Crusts resemble a soft, crumbly or sandy scab which, like sand, is often discernibly yellow. As lesions crust over, they frequently become extremely itchy.