Vaginal yeast infection, also known as candidal vulvovaginitis and vaginal thrush, is excessive growth of yeast in the vagina that results in irritation. The most common symptom is vaginal itching, which may be severe. Other symptoms include burning with urination, a thick, white vaginal discharge that typically does not smell bad, pain during sex, and redness around the vagina. Symptoms often worsen just before a woman's period.
Vaginal yeast infections are due to excessive growth of Candida. These yeast are normally present in the vagina in small numbers. Vaginal yeast infections are typically caused by the yeast species Candida albicans. Candida albicans is a common fungus often harbored in the mouth, digestive tract, or vagina without causing adverse symptoms. The causes of excessive Candida growth are not well understood, but some predisposing factors have been identified.
It is not classified as a sexually transmitted infection; however, it may occur more often in those who are frequently sexually active. Risk factors include taking antibiotics, pregnancy, diabetes, and HIV/AIDS. Tight clothing, type of underwear, and personal hygiene do not appear to be factors. Diagnosis is by testing a sample of vaginal discharge. As symptoms are similar to that of the sexually transmitted infections, chlamydia and gonorrhea, testing may be recommended.
Treatment is with an antifungal medication. This may be either as a cream such as clotrimazole or with oral medications such as fluconazole. Despite the lack of evidence, wearing cotton underwear and loose fitting clothing is often recommended as a preventive measure. Avoiding douching and scented hygiene products is also recommended. Probiotics have not been found to be useful for active infections.
Around 75% of women have at least one vaginal yeast infection at some point in their lives, while nearly half have at least two. Around 5% have more than three infections in a single year. It is the second most common cause of vaginal inflammation after bacterial vaginosis.
Signs and symptoms
The symptoms of vaginal thrush include vulval itching, vulval soreness and irritation, pain or discomfort during sexual intercourse (superficial dyspareunia), pain or discomfort during urination (dysuria) and vaginal discharge, which is usually odourless. Although the vaginal discharge associated with yeast infection is often described as thick and lumpy, like paper paste or cottage cheese, it can also be thin and watery, or thick and of uniform texture. In one study, women with vaginal yeast infection were no more likely to describe their discharge as cottage-cheese like than women without.
As well as the above symptoms of thrush, vulvovaginal inflammation can also be present. The signs of vulvovaginal inflammation include erythema (redness) of the vagina and vulva, vaginal fissuring (cracked skin), edema (swelling from a build-up of fluid), also in severe cases, satellite lesions (sores in the surrounding area). This is rare, but may indicate the presence of another fungal condition, or the herpes simplex virus (the virus that causes genital herpes).
Vaginal candidiasis can very rarely cause congenital candidiasis in newborns.
Causes
Medications
Infection occurs in about 30% of women who are taking a course of antibiotics by mouth. Broad-spectrum antibiotics kill healthy bacteria in the vagina, such as Lactobacillus. These bacteria normally help to limit yeast colonization.
Oral contraceptive use is also associated with increased risk of vaginal thrush.
Pregnancy
In pregnancy, higher levels of estrogen make a woman more likely to develop a yeast infection. During pregnancy, the Candida fungus is more common, and recurrent infection is also more likely. There is tentative evidence that treatment of asymptomatic candidal vulvovaginitis in pregnancy reduces the risk of preterm birth.
Lifestyle
While infections may occur without sex, a high frequency of intercourse increases the risk. Personal hygiene methods or tight-fitting clothing, such as tights and thong underwear, do not appear to increase the risk.
Diseases
Those with poorly controlled diabetes have increased rates of infection while those with well controlled diabetes do not. The risk of developing thrush is also increased when there is poor immune function, as with HIV/AIDS, or in those receiving chemotherapy.
Diet
A diet high in sugar may increase the risk of vaginal thrush; in some women, reducing sugar intake seems to reduce the risk of reoccurring vaginal thrush.