Thrush, bacterial vaginosis, trichomoniasis, chlamydia and gonorrhoea are the most common causes of vaginal infection. Other infections include genital herpes and genital warts. Each of these is described below.

A foreign body, such as a forgotten tampon, can also promote infection and cause an offensive discharge.

In addition to a discharge, itchiness and soreness, other warning signs of an infection include:

• a fishy smell
• painful intercourse
• abdominal pains
• redness, swelling, lumps, blisters, sore spots or ulceration of the vulva (the skin around the outside of the vagina) or anus
• pain when passing urine

So that a doctor can diagnose a vaginal infection, he or she may need to examine the outer genital skin and the inner vaginal lining. An instrument called a speculum, the same as used for a smear test, is sometimes used. A sample of discharge may be taken using a swab, which looks like a long cotton bud. This is sent to a laboratory for analysis.

Thrush
Almost all women have the fungus Candida albicans growing harmlessly on and in their bodies. However, when it grows excessively, it causes thrush (vaginal candidiasis). Irritation and soreness of the vulva are the usual symptoms, sometimes but not always, accompanied by a thick, white vaginal discharge. If left untreated, the irritation can spread to the area between the buttocks. Passing urine and intercourse can be painful.

Pregnancy, menstruation, diabetes, wearing tight underwear and antibiotics are all possible triggers of an attack of thrush.

Most thrush infections respond to one of the antifungal treatments such as clotrimazole creams and pessaries (eg Canestan), or fluconazole (Diflucan) tablets, that are available from your doctor. You may also ask your pharmacist for advice. If the treatment doesn't work or the symptoms return, see your doctor. Antifungal drugs or a longer course of fluconazole tablets may be prescribed. There's no good evidence that treating a woman's partner helps, unless he has a rash or soreness of the penis.

Wearing cotton pants, changed daily, and avoiding harsh soaps, bubble baths and deodorants may help prevent thrush. Vaginal douches are not recommended to treat or prevent vaginal infections, including thrush, as they disturb the natural, and protective, acidity of the vagina.

Bacterial vaginosis
Bacterial vaginosis (BV) is the commonest cause of vaginal discharge in women of childbearing age. It causes a fishy smell and occasionally vaginal itching and burning. BV symptoms can clear up without treatment before recurring. But, left untreated, the infection can cause miscarriages, premature labour and pelvic inflammatory disease (PID).

Bacterial vaginosis is caused when the bacteria normally found in the vagina (Lactobacillus) are overgrown by others (eg Gardnerella vaginalis), which are normally found in smaller numbers. Any woman with a fishy smelling discharge should seek medical advice, as the effective treatments - antibiotics in cream, gel or tablet form - are only available on prescription. This treatment is fairly effective in stopping the symptoms, but the condition often returns.

It is not clear how BV is related to sexual activity, although there may be a link with having a new sexual partner and a high lifetime number of sexual partners. The contraceptive coil seems to increase the risk of BV.

Trichomoniasis
The characteristic symptom of trichomonas infection is a heavy, frothy, yellow-green, unpleasant-smelling discharge. It can also cause discomfort during sex, vaginal itching, pain when passing urine and occasionally stomach pains. Research has linked trichomonas infection with infertility, increased risk of transmission of HIV, premature labour and low-birth-weight babies.

It is caused by a protozoan (a form of parasite) called Trichomonas vaginalis that is transmitted during sex. The treatment is with the antibiotic metronidazole, available only on prescription. Trichomoniasis may cause no symptoms in men, so male partners should also be treated.

Chlamydia
Chlamydia can cause pain when passing urine, long-term pelvic pain and infertility. However, it may produce no symptoms in women. It's also been associated with low birth weight babies and premature delivery. Infected male partners often complain of painful urination (non-specific urethritis).

Chlamydia is caused by the sexually transmitted bacterium Chlamydia trachomitis.

Treatment is usually with the antibiotics doxycycline, erythromycin or azithromycin.

Gonorrhoea
The main symptoms are vaginal discharge and pain passing urine, but there may be no symptoms in the early stages. Untreated, gonorrhoea can lead to pelvic infection, with abdominal pain, painful sex, and a general feeling of being unwell. Damage to the Fallopian tubes can result in reduced fertility and an increased risk of ectopic pregnancy (pregnancy in the tube rather than the womb).

The bacterium responsible is called Neisseria gonorrhoeae. Penicillin used to be the standard treatment, but as resistance is now a problem newer antibiotics are often used.

Genital herpes
Herpes infection can cause spots on the labia, clitoris and pubic area. These look like blisters, ulcers or chapped areas. People often have flu-like symptoms, fever and pain passing urine for about a week when first infected.

A pregnant woman can transmit the infection to her baby during delivery. Severe damage to the baby's nervous system can result.

The infection is caused by the herpes simplex virus being passed during sex. The virus lies dormant in the body and it's common to get repeated attacks. These are generally milder than the first attack. Sometimes a burning or tingling feeling is felt beforehand. There's no cure for herpes, but antiviral drugs (such as aciclovir tablets) can help to shorten the first attack, and reduce the severity of further episodes. Some people find salt baths, ice packs and painkillers helpful. Frequent severe attacks may require regular antiviral treatment for up to a year.

The virus is most infectious during an attack, so avoiding sexual activity at this time lessens the chance of passing it to others.

Genital warts
These appear as small round lumps on or around the genitals. They're caused by the human papilloma virus (HPV), which is passed by skin-to-skin contact. Exposure to HPV increases the risk of developing cervical cancer.

Although there's no cure for the virus, a variety of treatments are available to remove individual warts, including creams, application of liquid nitrogen and laser surgery. Removing the warts as they arise does reduce the chance of passing on the infection.

Safer sex
Chlamydia, gonorrhoea, herpes and trichomoniasis are sexually transmitted diseases (STDs) that can cause vaginal symptoms. However some STDs do not cause symptoms. As a condom provides good protection against many STDs, one should always be used unless both partners are entirely sure that they have not been exposed to infection.

If you suspect you have an STD, or other genital or urinary infection, see your doctor.

This information was published by Bupa Group's Health Content Team and has been reviewed by appropriate medical or clinical professionals. To the best of their knowledge the information is current and based on reputable sources of medical evidence, however Bupa (Asia) Limited makes no representation or warranty as to the completeness or accuracy of the Content.

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