Author: Dr Amanda Oakley, Dermatologist, Hamilton, New Zealand; Reviewed by Dr Jennifer Bradford, Gynaecologist, Sydney, Australia, 2011.
Labia is the medical term for lips. Labia usually refer to the lips of female genitalia. The labia cover and protect the urethral opening (the urethra is the passageway to the bladder) and the vagina. There are two outer lips, the labia majora, and two inner lips, the labia minora.
The labia majora are usually covered with sparse pubic hair and are considered a skin structure. The labia minora are an interface structure with an outer hair-free skin surface and an inner mucosal surface. The labia minora look like flaps or wings, and they can be a few millimetres to several centimetres in length.
Labial adhesion means that the labia minora are stuck together (fused). Adhesion rarely results in complete labial fusion; more often it is partial. The adhesion may also be called bridging, as the right and left side of the vulva are joined together. Labial adhesion may also refer to fusion of labium minor with labium major.
Secondary labial adhesion usually occurs after menopause. Labial adhesion in prepubertal girls is often present since birth and is known as primary labial adhesion.
Secondary labial adhesion may be due to oestrogen deficiency, particularly in non-sexually active women after the menopause. It may also be caused by scarring or fibrous tissue that forms after severe inflammatory skin disease, surgery or trauma. The most common causes of labial adhesion in adult women are listed below.
Labial adhesion joining the left and right labia minora results in a narrowed vaginal opening (the vaginal introitus).
The vaginal introitus is normally several centimetres in length and in adults can easily stretch to accomodate a penis during sexual intercourse, and at the end of pregnancy, a baby's head. When the labia are fused together, the opening is smaller and the skin can't stretch. The introitus can be as small as a pinhead when labial adhesions are severe. Symptoms may be absent or the adhesion may lead to:
Adhesion between a labium minor and corresponding labium major results in resorption, shrinking or disappearance of the labium minor.
Characteristics of labial adhesion
Other features depend on the condition causing labial adhesions and may include:
The internal tissues of the vagina may be quite normal but inflammation and scarring may affect the vaginal lining as well as the external genitalia in some inflammatory skin disorders, particularly erosive lichen planus and mucous membrane pemphigoid. The vagina may also be scarred following surgery or trauma.
Partial labial adhesion may be unobserved but often, symptoms and complications arise. These include:
Complete labial fusion means that urine and vaginal fluids including menstrual blood build up behind the fused labia; this is an emergency and urgent medical assistance should be sought.
Treatment depends on the cause of the fusion. It does not always require specific treatment.
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