Oral thrush is a condition in which the fungus Candida albicans accumulates on the lining of your mouth.

Oral thrush causes creamy white lesions, usually on your tongue or inner cheeks. The lesions can be painful and may bleed slightly when you scrape them or brush your teeth. Sometimes oral thrush may spread to the roof of your mouth, your gums, tonsils or the back of your throat.

Although oral thrush can affect anyone, it occurs most often in babies and toddlers, older adults, and in people with compromised immune systems. Oral thrush is a minor problem for healthy children and adults, but for those with weakened immune systems, symptoms of oral thrush may be more severe, widespread and difficult to control.

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Oral thrush

Oral thrush usually produces creamy white lesions on your tongue and inner cheeks and sometimes on the roof of your mouth, gums and tonsils. The lesions, which resemble cottage cheese, can be painful and may bleed slightly when rubbed or scraped. Although oral thrush symptoms often develop suddenly, they may persist for a long time.

In severe cases, the lesions may spread downward into your esophagus — the long, muscular tube stretching from the back of your mouth to your stomach (Candida esophagitis). If this occurs, you may experience difficulty swallowing or feel as if food is getting stuck in your throat.

Signs and symptoms in infants and breast-feeding mothers
Healthy newborns with oral thrush usually develop symptoms during the first few weeks of life. In addition to the distinctive white mouth lesions, infants may have trouble feeding or be fussy and irritable. They can also pass the infection to their mothers during breast-feeding. The infection may then pass back and forth between mother's breasts and baby's mouth. Women whose breasts are infected with candida may experience the following signs and symptoms:

• Unusually red or sensitive nipples
• Shiny or flaky skin on the areola
• Unusual pain during nursing or painful nipples between feedings
• Stabbing pains deep within the breast

Microorganisms such as viruses, bacteria and fungi are everywhere, including in and on your own body. In general, the relationship between you and the microorganisms in your body is mutually beneficial. You provide nutrition, protection and transportation for them, while they stimulate your immune system, synthesize essential vitamins, and help protect against harmful viruses and bacteria.

But your relationship to microorganisms in the world at large is more complex. Some microbes are highly beneficial, whereas others — such as those that cause malaria and meningitis — can be deadly. For that reason, your immune system works to repel harmful invading organisms while maintaining a balance between "good" and "bad" microbes that normally inhabit your body.

But sometimes these protective mechanisms fail. Oral thrush and other candida infections occur when your immune system is weakened by disease or drugs such as prednisone, or when antibiotics disturb the natural balance of microorganisms in your body.

These illnesses may make you more susceptible to oral thrush infection:

• Chronic mucocutaneous candidiasis. This group of rare disorders is marked by a chronic candida infection of your mouth and fingernails and of the skin on your scalp, trunk, hands and feet. Scaly, crusted lumps known as granulomas also may develop in your mouth or on your nails and skin.
• HIV/AIDS. The human immunodeficiency virus (HIV) — the virus that causes AIDS — damages or destroys the cells of your immune system, making you more susceptible to opportunistic infections your body would normally resist. One of the most common opportunistic infections is oral thrush. Thrush is rare in the early stage of AIDS. It usually only appears if levels of the virus-fighting cells known as CD4 fall below 300.
• Cancer. If you're dealing with cancer, your immune system is likely to be weakened both from the disease and from treatments such as chemotherapy and radiation, increasing your risk of candida infections such as oral thrush.
• Diabetes mellitus. If you don't know you have diabetes or the disease isn't well controlled, your saliva may contain large amounts of sugar, which encourages the growth of candida.
• Vaginal yeast infections. Many women experience at least one vaginal yeast infection (Candida vulvovaginitis) before menopause. Vaginal yeast infections are caused by the same fungus that causes oral thrush. Although a yeast infection isn't dangerous, if you're pregnant you can pass the fungus to your baby during delivery. As a result, your newborn may develop oral thrush within the first several weeks after birth.

Anyone can develop oral thrush, but the infection is especially common in infants and toddlers whose immune systems aren't fully developed. In addition, babies can pass the infection to their mothers during breast-feeding.

You're also more likely to develop oral thrush if you:

• Are an older adult
• Have a compromised immune system
• Use oral corticosteroids or antibiotics
• Use a corticosteroid inhaler for asthma

If you or your baby develops painful white lesions inside the mouth, see your doctor or dentist.

If thrush develops in older children or adolescents who have no other risk factors, seek medical care. An underlying condition such as diabetes may be the cause.

Oral thrush can usually be diagnosed simply by looking at the lesions, but sometimes a small sample is examined under a microscope to confirm the diagnosis.

In older children or adolescents who have no other risk factors, an underlying medical condition may be the cause of oral thrush. If your doctor suspects that to be the case, your doctor will perform a thorough physical exam as well as recommend certain blood tests to help find the source of the problem.

Thrush that extends into the esophagus can be serious. To help diagnose this condition, your doctor may ask you to have one or more of the following tests:

• Throat culture. In this procedure, the back of your throat is swabbed with sterile cotton and the tissue sample cultured on a special medium to help determine which bacteria or fungi, if any, are causing your symptoms.

• Endoscopic examination. In this procedure, your doctor examines your esophagus, stomach and the upper part of your small intestine (duodenum) using a lighted, flexible tube with a camera on the tip (endoscope). The test, called an esophagogastroduodenoscopy, takes between 30 and 60 minutes.

  You'll be given a sedative to make you more comfortable and a local anesthetic so that you don't cough or gag when the endoscope is inserted. There's a slight risk of perforation of your esophagus, stomach or duodenum and of an adverse reaction to medication you may be given.

• Barium swallow. In this test, you'll need to drink one or two barium "milkshakes" — glasses of thick, chalky liquid that may be flavored so they go down more easily. X-rays are then taken as the barium flows through your esophagus into your stomach.

Oral thrush is seldom a problem for healthy children and adults, although the infection may return even after it's been treated. For people with compromised immune systems, however, thrush can be more serious.

People with HIV may have especially severe symptoms in their mouth or esophagus, which can make eating painful and difficult. If the infection spreads to the intestines, it becomes difficult to receive adequate nutrition, just when it's needed most. In addition, thrush is more likely to spread to other parts of the body in people with cancer, HIV or other conditions that weaken the immune system. In that case, the areas most likely to be affected include the digestive tract, lungs and liver.

The goal of any oral thrush treatment is to stop the rapid spread of the fungus, but the best approach may depend on your age and the cause of the infection.

Treating oral thrush in children
Toddlers with mild oral thrush who are otherwise healthy may need no treatment at all. If the infection develops after a course of antibiotics, your doctor may suggest adding unsweetened yogurt to your child's diet to help restore the natural balance of bacteria. Infants or older children with persistent thrush may need an antifungal medication.

Treating oral thrush in infants and nursing mothers
If you're breast-feeding an infant who has oral thrush, you and your baby will do best if you're both treated. Otherwise, you're likely to pass the infection back and forth. Your doctor may prescribe a mild antifungal medication for your baby and an antifungal cream for your breasts. If your baby uses a pacifier or feeds from a bottle, wash and rinse nipples and pacifiers in a mixture of equal parts of white vinegar and water every day until the thrush clears up.

Treating oral thrush in healthy adults
If you're a healthy adult with oral thrush, you may be able to control the infection by eating unsweetened yogurt or taking acidophilus capsules or liquid. Acidophilus is available in natural food stores and many drugstores. Some brands need to be refrigerated to maintain their potency. Yogurt and acidophilus don't destroy the fungus, but they can help restore the normal bacterial flora in your body. If this isn't effective, your doctor may prescribe an antifungal medication.

Treating oral thrush in adults with weakened immune systems
Most often, your doctor will recommend an antifungal medication, which may come in one of several forms, including lozenges, tablets or a liquid that you swish in your mouth and then swallow.

Candida albicans can become resistant to antifungal medications, especially in people with late-stage HIV infection. A drug known as amphotericin B may be used when other medications aren't effective.

Some antifungal medications may cause liver damage. For this reason, your doctor will likely perform blood tests to monitor your liver function, especially if you require prolonged treatment or have a history of liver disease.

The following measures may help reduce your risk of developing candida infections:

• Rinse your mouth. If you have to use a corticosteroid inhaler, be sure to rinse your mouth or brush your teeth after taking your medication.
• Try using fresh-culture yogurt containing Lactobacillus acidophilus or bifidobacterium or take acidophilus capsules when you take antibiotics.
• Treat any vaginal yeast infections that develop during pregnancy as soon as possible.
• See your dentist regularly — at least every six to 12 months — especially if you have diabetes or wear dentures. Brush and floss your teeth as often as your dentist recommends. If you wear dentures, be sure to clean them thoroughly and often.
• Watch what you eat. Try limiting the amount of sugar and yeast-containing foods you eat, including bread, beer and wine. These may encourage the growth of candida.

These suggestions may help during an outbreak of oral thrush:

• Practice good oral hygiene. Brush at least twice a day and floss at least once. Replace your toothbrush frequently until your infection clears up. If you have problems with strength or dexterity in your hands, an electric toothbrush can make brushing easier. Avoid mouthwash or sprays — they can destroy the normal flora in your mouth.
• Try warm saltwater rinses. Dissolve 1/2 teaspoon of salt in 1 cup of warm water. Swish the rinse and then spit it out, but don't swallow.
• Use nursing pads. If you're breast-feeding and develop a fungal infection, this will help prevent the fungus from spreading to your clothes. Look for pads that don't have a plastic barrier, which can encourage the growth of candida.

Some research has suggested that garlic may have antifungal and antibacterial properties. Garlic capsules, raw garlic or garlic paste may be beneficial, but check with your doctor before trying any alternative treatments to ensure that they won't interact with other medications you're taking.