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Author: Dr Amanda Oakley, Dermatologist, Hamilton, New Zealand, 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 fatty folds of skin which develop hair on the outer surface at puberty. The labia minora are a modified skin structure forming small flaps covering the vagina. They are much smaller in infants than in adult women. In adults, prominent sebaceous glands may be observed on the labia minora.
Labial adhesion means the labia minora are stuck together. This is sometimes called 'labial fusion'.
Labial adhesion since birth (prepubertal adhesions) are known as primary labial adhesions and are described here.
Secondary labial adhesion follows atrophy or resorption of the labia and/or scarring and are described elsewhere. Secondary labial adhesion usually occurs later in life but may rarely affect infants and children with inflammatory skin diseases such as lichen sclerosus. These diseases may result in shrinking or complete absence of the labia minora.
Primary labial adhesion most commonly affects prepubertal girls aged 3 months to 8 years.
On close inspection, the lips are completely or partially closed together, with a central line. A membrane may be seen covering the vaginal opening between the labia minora. It usually starts at the back of the vaginal opening and leaves a gap at the front.
Primary labial adhesion does not usually cause any problems in childhood. However:
Primary labial adhesion arises in infants when there is very little circulating oestrogen hormone (American spelling estrogen). It is thought the adhesion occurs after local irritation by urine, scratching or uncomfortable underwear (contact irritant dermatitis), or after urinary infection.
Other disorders should be ruled out:
If the adhesion is mild and causing no problems, treatment is not required and the labia may be expected to separate by themselves at puberty. An emollient can be applied if the vulva is irritated.
If treatment is necessary, oestrogen cream may be prescribed to apply to the labia and is usually successful. At first a small amount is applied once daily for 2-4 weeks. Once the labia are separated, oestrogen cream can usually be stopped and replaced by an emollient cream for a few months. In some girls, oestrogen cream may need to be applied intermittently (perhaps once or twice weekly) until puberty is established.
Gentle division of the adhesion may be possible by simply stretching the two sides until they separate. But this may cause further irritation so that adhesion recurs.
Surgery may be required to divide severe fibrous adhesion using local anaesthetic cream or under general anaesthesia. Oestrogen cream is usually prescribed afterwards to prevent the labia sticking together again.
It is not always possible to prevent labial adhesion. Minimise contact with irritants. Use non-soap cleanser or water alone. Avoid bubble baths.
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