What Is Oral Thrush?
Oral thrush, also called oral candidiasis, is a fungal infection of the mouth and throat. It is caused by Candida albicans, a type of yeast that normally lives on the skin and mucous membranes without causing problems. When something disrupts the natural balance of organisms in your mouth, Candida can multiply rapidly and cause an infection.
Oral thrush appears as creamy white or yellowish patches on the tongue, inner cheeks, roof of the mouth, gums, or back of the throat. These patches may look like cottage cheese and can sometimes be wiped away, leaving red, raw tissue underneath that may bleed. Some people also experience a cottony feeling in the mouth, loss of taste, or pain when eating or swallowing.
While oral thrush can affect anyone, it is most common in babies, older adults, people who wear dentures, and individuals with weakened immune systems.
What Causes Oral Thrush?
Oral thrush develops when something allows Candida yeast to grow beyond its normal levels. Several factors can tip this balance.
Antibiotic Use
Antibiotics kill bacteria, including the beneficial bacteria in your mouth that normally keep Candida in check. When these bacteria are reduced, Candida can overgrow and cause thrush. This is one of the most common triggers, particularly after a long course of broad-spectrum antibiotics.
Dry Mouth
Saliva contains antifungal proteins that help control Candida growth. When saliva production decreases, whether from medications, radiation therapy, Sjogren's syndrome, or mouth breathing, the mouth becomes more susceptible to fungal infection. Many common medications, including antihistamines, blood pressure drugs, and antidepressants, can cause dry mouth.
Diabetes
People with uncontrolled diabetes have higher sugar levels in their saliva, which provides extra fuel for Candida growth. Managing blood sugar levels is an important part of preventing recurring oral thrush in people with diabetes.
Weakened Immune System
Conditions that suppress the immune system increase the risk of oral thrush significantly. These include HIV/AIDS, cancer treatment (chemotherapy and radiation), organ transplant medications, and long-term use of corticosteroids. For people with severely weakened immune systems, oral thrush can spread to the esophagus and become a more serious condition.
Inhaled Corticosteroids
People who use inhaled corticosteroids for asthma or COPD are at increased risk of oral thrush. Steroid particles that land in the mouth and throat can suppress the local immune response and promote Candida growth. Rinsing the mouth with water after each inhaler use can significantly reduce this risk.
Other Risk Factors
- Wearing dentures, especially if they are not cleaned daily or do not fit properly
- Smoking, which changes the environment in the mouth
- Nutritional deficiencies, particularly iron, vitamin B12, or folate
- Age: infants and adults over 65 are more susceptible
- Recent dental procedures or oral surgery
Symptoms of Oral Thrush
Oral thrush symptoms can develop suddenly or gradually. The infection can range from mild and barely noticeable to painful and widespread.
- White or yellowish patches on the tongue, inner cheeks, roof of the mouth, gums, or tonsils
- Redness or soreness that may be severe enough to cause difficulty eating and swallowing
- Cracking and redness at the corners of the mouth (angular cheilitis)
- A cottony or dry feeling in the mouth
- Loss of taste or an unpleasant taste
- Pain or burning sensation, especially when eating spicy or acidic foods
- Slight bleeding if the white patches are rubbed or scraped
When Oral Thrush Spreads
In people with weakened immune systems, oral thrush can spread beyond the mouth to the esophagus (esophageal candidiasis). Symptoms of esophageal involvement include pain or difficulty swallowing, a feeling that food is stuck in the throat, and chest pain. This is a more serious condition that requires systemic antifungal treatment and medical evaluation.
How Oral Thrush Is Treated
Oral thrush treatment depends on the severity of the infection and the patient's overall health. Most cases respond well to antifungal medications.
Topical Antifungal Medications
For mild to moderate oral thrush, doctors typically prescribe topical antifungal medications that are applied directly in the mouth. Nystatin oral suspension is one of the most commonly used treatments. You swish the liquid around your mouth for several minutes and then swallow it. Clotrimazole lozenges (troches) are another option, dissolved slowly in the mouth several times a day.
Topical treatments are usually continued for 7 to 14 days, or for at least 48 hours after symptoms have cleared. Stopping treatment too early can allow the infection to return.
Oral Antifungal Medications
For moderate to severe cases, or when topical treatment has not worked, a doctor may prescribe fluconazole, an antifungal pill taken once daily. Fluconazole is often used as a first-line treatment for patients with weakened immune systems because it works throughout the body, not just in the mouth.
Other systemic antifungals, such as itraconazole, may be used for infections that do not respond to fluconazole. Your doctor will choose the medication based on the severity of your infection and any other medications you are taking.
Treating the Underlying Cause
Antifungal medications treat the active infection, but addressing the underlying cause is essential to prevent recurrence. If the thrush developed after antibiotics, it may not recur once the antibiotics are finished. If dry mouth, uncontrolled diabetes, or immune suppression is the trigger, managing that condition is a key part of long-term prevention.
For patients using inhaled corticosteroids, switching to a spacer device and rinsing the mouth after each use can prevent future episodes. Your doctor may also adjust your medication if thrush keeps recurring.
Oral Thrush in Denture Wearers
Denture wearers face a particularly high risk of oral thrush. The tissue under a denture provides a warm, moist environment where Candida thrives. Denture stomatitis, a form of oral thrush that causes redness and inflammation under the denture, affects up to two-thirds of denture wearers at some point.
If you wear dentures and develop oral thrush, it is critical to treat both your mouth and your dentures. Candida can live on the denture surface, and if the dentures are not disinfected, they will reinfect your mouth even after antifungal treatment clears the oral infection.
Denture Care to Prevent Thrush
- Remove dentures at night to let the tissue rest and dry out.
- Clean dentures daily with a denture brush and denture cleanser. Do not use regular toothpaste, which can scratch the surface and create places for Candida to grow.
- Soak dentures overnight in a denture-cleaning solution or a dilute chlorhexidine solution as recommended by your dentist.
- Make sure dentures fit properly. Ill-fitting dentures create more irritation and trap more bacteria and yeast.
- See your dentist regularly for denture adjustments and oral exams.
How to Prevent Oral Thrush
While not every case of oral thrush can be prevented, these steps can reduce your risk.
- Practice good oral hygiene: brush twice daily with a soft-bristled toothbrush and floss daily.
- Rinse your mouth with water after using an inhaled corticosteroid.
- Stay hydrated and address dry mouth with sugar-free lozenges, sips of water, or saliva substitutes if recommended by your dentist.
- Limit sugar and yeast-containing foods when you are at higher risk, such as during or after antibiotic treatment.
- If you wear dentures, follow proper cleaning and storage routines.
- See your dentist for regular checkups, especially if you have diabetes, a weakened immune system, or wear dentures.
- Do not use mouthwash excessively, as it can disrupt the natural balance of organisms in your mouth.
Oral Thrush Treatment Cost
The cost of treating oral thrush depends on the type of medication prescribed and your insurance coverage. Generic nystatin suspension and clotrimazole troches are relatively inexpensive, typically costing $10 to $30 with insurance or $15 to $50 without.
Fluconazole tablets are also available as a generic and typically cost $10 to $40 for a course of treatment. More specialized antifungal medications may cost more. A dental or medical office visit to diagnose and prescribe treatment generally ranges from $75 to $250. Costs vary by location and provider.
Most medical and dental insurance plans cover oral thrush treatment. If you have a prescription drug plan, antifungal medications are usually covered as well.
When to See a Specialist for Oral Thrush
Most cases of oral thrush can be diagnosed and treated by your primary care doctor or general dentist. However, you should see a specialist if the infection does not respond to initial antifungal treatment, if thrush keeps recurring despite good hygiene and addressing known triggers, or if the infection appears to be spreading beyond the mouth.
An oral and maxillofacial surgeon or oral medicine specialist can evaluate persistent or unusual oral infections. If you have an underlying condition such as HIV, cancer, or uncontrolled diabetes, your treating physician should also be involved in managing recurring thrush. In some cases, a biopsy of the affected tissue may be needed to rule out other conditions that can look similar to oral thrush.
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