Vaginal discharge and odour are the commonest complaints although a proportion of women are asymptomatic. A homogeneous, greyish white, adherent discharge is present in the vagina, the pH of which is raised (greater than 5). Associated complications are ill-defined but may include chorioamnionitis and an increased incidence of premature labour in pregnant women. Whether BV disposes non-pregnant women to upper genital tract infection is unclear.
Different authors have differing criteria for making the diagnosis of BV. In general it is accepted that three of the following should be present for the diagnosis to be made:
1 Characteristic vaginal discharge.
2 A raised vaginal pH using narrow range indicator paper (>4.7).
3 A fishy odour on mixing a drop of discharge with 10% potassium hydroxide.
4 The presence of clue cells on microscopic examination of the vaginal fluid. Clue cells are squamous epithelial cells from the vagina which have bacteria adherent to their surface giving a granular appearance to the cell. A Gram stain gives a typical mixed reaction. Additional laboratory tests include cultures for G. vaginalis but this is non-specific as the organism can be recovered in over 50% of women who do not meet the clinical diagnostic criteria for BV. Metabolic by-products of the altered vaginal flora may be detected using gas or thin layer chromatography.
Metronidazole given orally in doses of 800-1200 mg daily for 5-7 days is usually recommended. A single dose of 2 g metronidazole is less effective. Penicillins and other J3-lactam antibiotics are much less useful presumably because of J3-lactamase production by anaerobes. Topical clindamycin is being evaluated in the UK and is available in the USA where it seems efficacious. Topical acetic acid gel has been used with mixed results.
The rate of recurrence is high with some studies giving a recurrence rate of 80% within 9 months of completing metronidazole therapy. There is debate over the treatment of asymptomatic women who fulfil the diagnostic criteria for BV. The diagnosis should be fully discussed and treatment offered if the woman wishes. Until the relevance of BV to other pelvic infections is elucidated the routine treatment of all women with BV is not to be recommended. There is no convincing evidence that simultaneous treatment of the male partner influences the rate of recurrence of BV and routine treatment of male partners is not indicated.
The pubic louse (Phthirius pubis) is a blood-sucking insect which attaches tightly to the pubic hair. It is rela-tively host specific and is transferred only by close bodily contact. Eggs (nits) are laid at hair bases and hatch within a week. Although infestation may be asymptomatic the commonest complaint is of itch.
Lice may be seen on the skin at the base of pubic hairs. They may resemble small scabs or freckles but if they are picked up with forceps and placed on a microscope slide will move and walk away. Nits are usually closely adherent to hairs. Both are highly characteristic under the low power microscope. As with all sexually transmitted infections the patient must be screened for coexisting pathogens.
It is important that both lice and eggs are killed. This is achieved with 1% y-benzene hexachloride or 0.5% malathion. The preparation should be applied to all areas of the body from the neck down and washed off after 24 hours. In a few cases a further application at 1 week may be necessary. In severe infestations antipruritics may be indicated for the first 48 hours. All sexual partners should be seen and screened.