Vulvovaginal candidiasis is a common fungal infection affecting the vagina and surrounding skin. It causes uncomfortable symptoms like itching, burning, and discharge, but rarely leads to serious health complications. Understanding what triggers these infections and how to manage them can help women feel more in control of their health.
Epidemiology
Vulvovaginal candidiasis, often called a vaginal yeast infection, affects a large number of women worldwide. An estimated 75% of women will experience at least one episode during their lifetime, making it one of the most frequent reasons for visiting a gynecologist.[3][1] About 40% to 45% of women will have two or more episodes, showing just how common recurrence can be.[3]
The infection is most common in women during their reproductive years, particularly after puberty and before menopause. This pattern is closely tied to hormonal changes that occur during these life stages.[1][7] The condition is quite uncommon in young girls before puberty and in older women after menopause, unless they are using hormone replacement therapy.[7]
Vulvovaginal candidiasis accounts for approximately one-third of all cases of inflammation affecting the vulva and vagina.[2] Despite being extremely prevalent, many women do not seek medical care immediately, instead trying to self-diagnose and treat the condition with over-the-counter products. However, studies show that only about 11% of women can accurately identify a yeast infection based on symptoms alone.[5]
Causes
Vulvovaginal candidiasis is caused by an overgrowth of yeast, most commonly a fungus called Candida albicans. This fungus is actually a normal part of the body’s natural environment and lives in the vagina of many healthy women without causing any problems.[1] In fact, about 10% to 20% of women carry Candida species in their vagina without experiencing any symptoms at all.[2][3]
Yeast infections develop when something disrupts the natural balance of bacteria and yeast in the vagina. Under normal circumstances, beneficial bacteria help keep the yeast population under control. When this balance is thrown off, Candida can multiply rapidly and cause infection. The fungus thrives in environments that are warm and moist, which is why the vaginal area can be particularly vulnerable.[1]
While Candida albicans is responsible for most infections, other species of Candida can also cause problems. These include Candida glabrata, Candida tropicalis, Candida krusei, and others. About 10% to 20% of women with recurrent infections are affected by these non-albicans species, which can sometimes be more resistant to standard treatments.[7][12]
It’s important to understand that vulvovaginal candidiasis is not considered a sexually transmitted infection. Women who are not sexually active can develop yeast infections, and the condition can occur without any sexual contact. However, sexual activity can sometimes play a role in transmitting the infection between partners, though this is uncommon. Oral-genital contact may also be linked to some cases.[4][1]
Risk Factors
Certain factors increase the likelihood of developing a vaginal yeast infection. One of the most common triggers is taking antibiotics. These medications are designed to kill harmful bacteria causing infections elsewhere in the body, but they also destroy the beneficial bacteria in the vagina that normally keep yeast under control. Without enough good bacteria, yeast can multiply freely and cause infection.[1][12]
Hormonal changes are another significant risk factor. Pregnancy causes major shifts in hormone levels, which can disrupt the vaginal environment and make infections more likely. Similarly, using birth control pills, especially those containing higher doses of estrogen, can increase risk. Even normal hormonal fluctuations during the menstrual cycle can trigger infections, with symptoms often appearing in the second half of the cycle.[1][7]
Women with diabetes, particularly those whose blood sugar levels are not well controlled, face a higher risk of yeast infections. Excess sugar in the body can feed the yeast in the vagina, helping it grow. Additionally, unmanaged diabetes weakens the immune system, making it harder for the body to fight off infections.[1]
Having a weakened immune system for any reason increases vulnerability to yeast infections. This includes women with HIV infection, those taking immunosuppressive medications like corticosteroids, or anyone with conditions that compromise immune function.[3][1]
Other risk factors include obesity, iron deficiency anemia, and even stress or other illnesses that affect overall health.[7] Women who use estrogen-based hormone replacement therapy after menopause, including vaginal estrogen creams, may also experience more frequent infections.[7]
Symptoms
The symptoms of vulvovaginal candidiasis can range from mild discomfort to severe irritation that significantly affects daily life. The most common symptom is intense itching in and around the vagina. This itching can be constant and very bothersome, making it difficult to focus on normal activities.[1][3]
Many women experience a burning sensation in the vaginal area. This burning may be particularly noticeable when urinating or during sexual intercourse, which can also be painful. The burning and pain during sex, called dyspareunia, can strain intimate relationships and cause emotional distress.[3][7]
Changes in vaginal discharge are another hallmark of yeast infections. The discharge is typically thick and white, often described as looking like cottage cheese. Unlike some other types of vaginal infections, the discharge from a yeast infection usually has little or no odor.[1][4] The amount of discharge can vary from woman to woman.
Physical examination of the affected area often reveals redness and swelling of the vulva, which is the external genital area surrounding the vaginal opening. The skin may appear bright red and inflamed. In some cases, small cuts or cracks may develop in the delicate skin of the vulva, and there may be visible marks from scratching.[2][7]
Inside the vagina, thick white patches may be visible on the vaginal walls. The entire vaginal area may look swollen and irritated. Some women also experience vaginal soreness and tenderness that persists even when not urinating or having sex.[3][4]
Symptoms can last anywhere from just a few hours to several days or even weeks if left untreated. In some women, symptoms may worsen just before menstruation and improve once their period begins.[7] It’s worth noting that these symptoms can feel similar to those caused by other vaginal conditions, so professional diagnosis is important.[1]
Prevention
While it may not be possible to completely prevent all yeast infections, there are several lifestyle changes and habits that can significantly reduce risk. One of the most important steps is maintaining good genital hygiene without overdoing it. The vaginal area should be kept clean and dry, but excessive washing can actually do more harm than good.[19]
Women should avoid using douches, scented soaps, feminine sprays, powders, and perfumed tampons or pads. These products can disrupt the natural balance of bacteria and yeast in the vagina. Instead, it’s better to clean the external genital area with plain water or a mild, unscented soap. After bathing, the area should be dried gently but thoroughly.[1][19][20]
Clothing choices can make a difference in preventing yeast infections. Wearing cotton underwear helps because cotton is breathable and doesn’t trap heat and moisture the way synthetic fabrics do. Some women find it helpful to sleep without underwear to allow more air circulation. Avoiding tight-fitting pants, leggings, pantyhose, and other restrictive clothing also helps keep the genital area cooler and drier.[1][19]
After swimming or exercising, it’s important to change out of wet bathing suits or damp workout clothes as soon as possible. Sitting in wet or sweaty clothing creates a warm, moist environment where yeast can thrive. Taking a quick rinse and changing into dry clothes helps prevent this problem.[23][18]
Proper bathroom habits also matter. When wiping after using the toilet, always wipe from front to back. This helps prevent spreading yeast or bacteria from the anal area to the vagina. During menstruation, tampons, pads, and panty liners should be changed regularly.[19][24]
Diet may play a role in preventing yeast infections, though research in this area is still developing. Some evidence suggests that diets high in sugar and simple carbohydrates may promote yeast growth, as yeast feeds on sugar. Reducing intake of sugary foods and beverages might help some women. On the other hand, eating yogurt with live bacterial cultures or taking probiotic supplements containing Lactobacillus bacteria may help maintain a healthy balance of vaginal flora.[18][23]
For women with diabetes, keeping blood sugar levels under good control is crucial for preventing recurrent yeast infections. When diabetes is well managed, the risk of yeast infections decreases significantly.[1][24]
Women using vaginal medications should avoid sexual intercourse until treatment is complete, or if they do have sex, they should not rely on latex condoms or diaphragms for contraception, as the oil in some vaginal medications can weaken latex.[19][24]
Pathophysiology
Understanding how vulvovaginal candidiasis develops requires knowing what happens in the vagina under normal, healthy conditions. The vaginal environment is naturally acidic, with a pH typically below 4.5. This acidity is maintained by beneficial bacteria, particularly Lactobacillus species, which produce lactic acid and other substances that keep harmful microorganisms in check.[3][7]
Candida albicans and related yeast species are part of the normal vaginal flora in many women. They exist in a dormant state, kept under control by the beneficial bacteria and the body’s immune defenses. In this balanced state, small numbers of yeast cause no symptoms and pose no problems.[2][16]
When something disrupts this delicate balance, the yeast can begin to multiply rapidly. The hormone estrogen plays an important role in this process. Estrogen causes the vaginal lining to mature and increases the amount of glycogen stored in vaginal cells. Glycogen is a type of sugar that serves as food for yeast. When estrogen levels are higher, such as during pregnancy, the second half of the menstrual cycle, or when taking birth control pills, there is more glycogen available for yeast to feed on.[7][6]
As yeast multiplies, it can change form. Candida albicans is a polymorphic fungus, meaning it can exist in different shapes. It can live as round yeast cells called blastospores, but when conditions are right for growth, it transforms into a filamentous form, developing long branches called hyphae or pseudohyphae. This filamentous form allows the fungus to penetrate into the cells of the vaginal lining, triggering inflammation.[2][6]
The immune system responds to this fungal invasion by sending inflammatory cells to the area. This immune response causes the redness, swelling, and itching that characterize yeast infections. The vaginal and vulvar tissue becomes inflamed and irritated. White, thick discharge accumulates as dead yeast cells, immune cells, and shed vaginal lining cells mix together.[2][6]
Unlike many other infections, vulvovaginal candidiasis typically occurs in women with normal, healthy immune systems. This is different from systemic Candida infections, which usually only affect people with severely compromised immunity. The reason yeast infections happen in otherwise healthy women relates more to local factors in the vaginal environment than to overall immune weakness.[6]
However, certain factors that weaken local defenses or alter the vaginal environment can tip the balance in favor of yeast overgrowth. Antibiotics kill beneficial Lactobacillus bacteria along with disease-causing bacteria, removing a key defense against yeast proliferation. Hormonal changes alter the vaginal environment and provide more food for yeast. Diabetes raises sugar levels throughout the body, including in vaginal secretions, giving yeast extra fuel for growth.[1][11]
The vagina’s pH level is also critical in this process. A healthy vaginal pH below 4.5 helps keep yeast in check. When the pH rises above this level, yeast can grow more easily. Unlike bacterial vaginosis, another common vaginal infection that raises pH, yeast infections typically maintain a normal acidic pH, which is why pH testing can help doctors distinguish between different types of vaginal infections.[3]
In women who experience recurrent yeast infections, the mechanisms may be more complex. Some research suggests that certain women may have genetic or immunological factors that make them more susceptible to repeated infections. The vaginal epithelial cells might respond differently to yeast, or the local immune response might not effectively clear the infection. Additionally, some yeast strains may be more virulent or resistant to the body’s natural defenses.[6][5]
