Thrush is a fungal infection caused by an overgrowth of Candida, a type of yeast that naturally lives on your skin and inside your body. It most commonly appears in the mouth (oral thrush) or the vagina (vaginal thrush), producing characteristic white patches or thick white discharge. Candida is normally kept in check by your immune system and the balance of other microorganisms, but when that balance is disrupted, the yeast multiplies and causes infection.
How Thrush Develops
Candida albicans, the species responsible for most thrush infections, exists harmlessly in small numbers in your mouth, gut, and genital area. Problems start when something weakens your body’s defenses or disrupts the community of bacteria that normally keeps Candida in check. When that happens, the yeast shifts from a harmless round form into a thread-like form that can physically penetrate tissue. It also releases enzymes that damage cells and help it spread deeper.
Several common situations trigger this overgrowth:
- Antibiotics kill off protective bacteria along with the harmful ones, giving Candida room to multiply unchecked.
- Inhaled steroids used for asthma suppress the local immune response in the mouth and throat, raising the risk of oral thrush.
- Uncontrolled diabetes creates persistently high blood sugar levels, which feeds yeast growth.
- Weakened immune systems from conditions like HIV/AIDS, cancer treatment, or immunosuppressant medications make it harder for the body to keep Candida under control.
Oral Thrush Symptoms
Oral thrush produces creamy white patches or spots on your tongue, inner cheeks, and sometimes the roof of your mouth, gums, or tonsils. These slightly raised patches have a texture often compared to cottage cheese. If you scrape or rub them, they may bleed slightly. Beyond the visible patches, you might notice a cottony feeling in your mouth, loss of taste, or burning and soreness severe enough to make eating and swallowing difficult.
Cracking and redness at the corners of the mouth is another telltale sign. If you wear dentures, you may feel redness, irritation, and pain underneath them. Oral thrush is especially common in infants, older adults with dentures, and people taking antibiotics or immunosuppressants.
In severe cases, particularly in people with cancer or HIV/AIDS, the infection can spread down into the esophagus. When that happens, swallowing becomes painful and food may feel like it’s getting stuck in your throat.
Vaginal Thrush Symptoms
Vaginal thrush (commonly called a yeast infection) causes itching and irritation in and around the vagina and vulva. The hallmark symptom is a thick, white discharge that looks like cottage cheese and has little or no odor. You may also experience a burning sensation during urination or intercourse, along with redness and swelling of the vulva. About three out of four women will have at least one vaginal yeast infection in their lifetime.
Thrush in Babies and Breastfeeding
Oral thrush is very common in newborns and young infants. You’ll see creamy white spots or patches on the tongue, gums, roof of the mouth, or insides of the cheeks. Unlike milk residue, these patches won’t come off if you gently wipe them with a clean cloth. Your baby may also have a white film on the lips, seem fussy during feeding, or develop a diaper rash that won’t clear up.
If you’re breastfeeding, thrush can pass back and forth between you and your baby. On the mother’s side, symptoms include a burning pain in the nipples (especially after feeds), itchy or touch-sensitive nipples, flaking or shiny skin on the nipple or areola, and sometimes white patches or tiny blisters. The nipple or areola may appear red on lighter skin, or darker brown, purple, or grey on darker skin tones. Because Candida thrives in warm, moist environments, breastfeeding creates ideal conditions for the fungus to take hold.
How Thrush Is Diagnosed
For oral thrush, a healthcare provider can usually make the diagnosis just by looking inside your mouth. The white patches are distinctive enough that lab tests aren’t always needed. If there’s any doubt, a small sample can be taken and examined under a microscope to confirm the presence of Candida. Vaginal thrush is diagnosed similarly, through a physical exam and sometimes a swab sent to a lab.
Treatment Options
Thrush is treated with antifungal medications. For oral thrush, treatment typically involves an antifungal liquid that you swish around your mouth before swallowing, or a pill taken once daily for one to two weeks. For vaginal thrush, a single oral antifungal dose is often enough to clear the infection. Antifungal creams or suppositories applied directly are another common option.
Most cases of thrush respond well to treatment within a week or two. If you use a steroid inhaler and keep getting oral thrush, rinsing your mouth with water after each use can help prevent it from coming back.
Preventing Recurrence
Some people, particularly with vaginal thrush, deal with repeated infections. Probiotics show promise as a complementary approach alongside standard antifungal treatment. A systematic review found that women who took probiotics containing Lactobacillus strains after antifungal therapy had significantly lower recurrence rates: only about 7% experienced a repeat infection at six months, compared to roughly 36% of women who took a placebo. Combining probiotics with standard antifungal medication also improved the odds of clearing the infection compared to antifungals alone.
Practical habits can also reduce your risk. For oral thrush, good dental hygiene and rinsing your mouth after using steroid inhalers make a real difference. For vaginal thrush, wearing breathable cotton underwear, avoiding scented products in the genital area, and keeping blood sugar well controlled if you have diabetes all help maintain the microbial balance that keeps Candida from overgrowing.