Thrush is a fungal infection caused by an overgrowth of a yeast called Candida albicans, a microscopic organism that naturally lives in and on your body. It most commonly appears in the mouth and throat (oral thrush) or the vagina (vaginal thrush), producing characteristic white patches or unusual discharge. Thrush is extremely common: up to 75% of women experience vaginal thrush at least once, and oral thrush is particularly frequent in newborns under one month old.
How Thrush Develops
Candida albicans is the most common species of Candida yeast, and it’s a normal resident of your skin, mouth, gut, and genital area. Healthy bacteria in your body, collectively called your microbiome, keep Candida populations in check. When something disrupts that balance, the yeast multiplies rapidly and causes infection.
Think of it like a garden where beneficial bacteria are the plants and Candida is a weed. Under normal conditions, the plants crowd out the weed. But if something kills off the plants, say a course of antibiotics, the weed takes over. That overgrowth is thrush.
Oral Thrush Symptoms
Oral thrush creates creamy white patches or spots, usually on the tongue or inner cheeks. These slightly raised patches have a texture often compared to cottage cheese. They can also spread to the roof of the mouth, gums, tonsils, or the back of the throat. If you scrape or rub the patches, they may bleed slightly.
Beyond the visible patches, oral thrush often causes:
- Burning or soreness that can make eating and swallowing difficult
- Cracking and redness at the corners of the mouth
- A cottony feeling in the mouth
- Loss of taste
In babies, thrush may cause fussiness, irritability, and trouble feeding. Nursing mothers can develop thrush on their nipples from contact with an infected baby, experiencing stabbing pains deep within the breast or unusual pain during and between feedings.
In severe cases, particularly in people with weakened immune systems from conditions like HIV/AIDS or cancer, the infection can spread down into the esophagus. When this happens, swallowing becomes painful and food may feel like it’s getting stuck in the throat.
Vaginal Thrush Symptoms
Vaginal thrush produces intense itching, burning, and pain in and around the vagina. The vaginal lining becomes red and may develop a whitish coating. If the inflammation spreads to the external genitals, the labia can become red and swollen. Sex is often painful during an active infection, and urination may sting if the urethra is also inflamed.
The discharge is distinctive: whitish-yellowish, and either watery or chunky, with a texture resembling curdled milk or cottage cheese. This discharge, combined with the itching, is usually enough for a diagnosis without laboratory testing.
Who Gets Thrush
Oral thrush is uncommon in healthy adults. The people most likely to develop it are newborns, older adults with dentures, and anyone with a compromised immune system. Several specific factors raise your risk:
- Antibiotics kill the beneficial bacteria that normally suppress Candida. The risk of developing thrush increases with longer courses of antibiotics.
- Inhaled corticosteroids used for asthma deposit medication in the mouth and throat, creating a hospitable environment for yeast.
- Diabetes provides elevated sugar levels that feed Candida growth.
- Dry mouth from medications or medical conditions removes saliva’s natural antifungal protection.
- Smoking reduces saliva production and changes the oral microbiome. Smokers face a sevenfold increase in oral Candida colonization compared to nonsmokers.
- HIV/AIDS and cancer weaken the immune system’s ability to keep yeast in check.
For vaginal thrush specifically, hormonal changes during pregnancy, the menstrual cycle, and oral contraceptive use can all shift the vaginal environment in Candida’s favor.
How Thrush Is Diagnosed
Oral thrush is usually diagnosed just by looking. The white patches are distinctive enough that a healthcare provider can identify the infection during a visual exam. If there’s any doubt, they may take a small swab from inside the mouth and send it to a lab to be examined under a microscope.
Vaginal thrush follows a similar process. A description of the symptoms combined with a visual examination of the vaginal lining is typically enough. If the diagnosis is uncertain, a sample of the discharge can be checked for yeast under a microscope.
Treatment and What to Expect
Thrush is treated with antifungal medications. For mild oral thrush, this usually means a medicated mouth rinse or lozenges that you dissolve in your mouth, allowing the medication to work directly on the infection. For vaginal thrush, antifungal creams or suppositories applied directly to the area are the standard first step. Single-dose oral antifungal tablets are also widely used for vaginal infections.
Mild cases typically clear up within one to two weeks. More stubborn or recurring infections, or those in people with weakened immune systems, may require longer treatment courses or stronger oral antifungal medications. If thrush keeps coming back, your provider may investigate underlying causes like uncontrolled diabetes or immune suppression.
Reducing Your Risk of Recurrence
Because thrush stems from a disrupted microbial balance, prevention centers on supporting the beneficial organisms that keep Candida in check.
If you use an inhaled corticosteroid for asthma, rinsing your mouth with water after each use helps wash away residual medication before it promotes yeast growth. If you wear dentures, cleaning them thoroughly each night and ensuring they fit properly reduces the warm, moist environment Candida thrives in.
Diet plays a meaningful role. A fiber-rich diet with plenty of vegetables supports a diverse gut microbiome, which in turn helps suppress fungal overgrowth. Probiotic-rich foods like yogurt with live cultures have shown real benefits. In one study, daily consumption of yogurt containing live Lactobacillus acidophilus eliminated recurrent vaginal thrush compared to pasteurized yogurt without live cultures. Probiotic bacteria compete directly with Candida for nutrients and attachment sites, and they can disrupt the protective films (biofilms) that yeast uses to establish itself.
Moderate exercise also helps. Physical activity boosts the function of immune cells that specifically target and destroy Candida. Quitting smoking is another high-impact change, given the sevenfold increase in oral Candida colonization among smokers. Limiting alcohol and managing stress round out the lifestyle factors that research has linked to healthier microbial balance and lower infection risk.