1. Pathogenesis

• trauma -> denudation of the superficial squamous epithelial layer of the labial minora mucosa -> fibrous tissue formation -> sealing of the labia minora in the midline along apposed areas of trauma
• types of trauma:
  • inflammatory conditions (vulvitis, vulvovaginitis) due to:
    • poor perineal hygiene
    • seborrhea
    • atopic dermatitis
    • pinworms
  • sexual abuse
  • masturbation
  • straddle injury
  • labial lacerations
• hypoestrogenism may result in a reduction in the thickness of the labial epithelial cells increasing the risk of trauma in this area

1. Genitourinary

• most girls are asymptomatic and labial fusion is found on routine physical examination
• flat vulva
• edges of the labia minora are sealed along the midline beginning at the posterior fourchette and extending anteriorly towards the clitoris
• a thin translucent membrane obscures the vaginal introitus and hymen

2. Complications

• distorted urinary stream
• post void dribbling of urine
• asymptomatic bacteriuria (in 20% of patients)
• urinary tract infection (in 20-40% of patients)
• urinary outflow obstruction -> bladder distension -> hydronephrosis

1. Urine

• urinalysis
• urine C&S

2. Imaging Studies

1. Conjugated Estrogen Cream (Premarin)

• apply a small amount of cream precisely to the fused area once or twice a day until the adhesion is lysed (usually in less than one month but may take up to two months)
• effective in 90% of cases

2. Prophylaxis

• apply Vasoline to the area once a day for 1-2 months after the adhesion has been lysed to prevent readhesion

3. Manual Separation

• not indicated
• high risk of recurrence and scarring

1. Leung, A., W. Robson, and B. Wong. Labial Fusion. Paediatrics & Child Health 1(3): 216-218 (1996).