Thrush is a yeast infection of the mucus membrane lining the mouth and tongue.A.D.A.M.

Causes, incidence, and risk factors

The body normally hosts a variety of germs ,including bacteria and fungi. Some of these are useful to the body, some produce no harm or benefit, and some can cause harmful infections.

Thrush occurs when a fungus called Candida overgrows in your mouth. A small amount of this fungus lives in your mouth most of the time. It is usually kep tin check by your immune system and other germs that also normally live in your mouth.

However, when your immune system is weak or when the other normal bacteria die, the fungus can overgrow. The following factors can increase your chances of getting thrush:

 The following factors can increase your chances of getting thrush:

• Being in poor health
• Being very old or very young
• Having an HIV infection or AIDS
• Long-term use or high dose antibiotics
• Receiving chemotherapy or drugs that weaken the immune system
• Taking steroid medications

Thrush is commonly seen in infants. It is not considered abnormal in infants unless it lasts longer than a couple of weeks.

Candida can also cause yeast infections in the vagina.

People who have diabetes and have high blood sugar levels are more likely to get thrush in the mouth (oral thrush), because the extra sugar in your saliva acts like food for Candida.

Taking high doses of antibiotics or taking antibiotics for a long time also increases the risk of oral thrush. Antibiotics kill some of the healthy bacteria that help keep Candida from growing too much.

People with poorly fitting dentures are also more likely to get thrush.

Symptoms

Thrush appears as whitish, velvety sores in the mouth and on the tongue. Underneath the whitish material, there is red tissue that may bleed easily. The sores can slowly increase in number and size.

Signs and tests

Your doctor or dentist can almost always diagnose thrush by looking at your mouth and tongue. The sores have a distinct appearance.

If the diagnosis is not clear, one of the following tests may be performed to look for Candida:

• Culture of mouth lesions
• Microscopic examination of mouth scrapings

Treatment

For thrush in infants, treatment is often NOT needed. It usually gets better on its own within 2 weeks.

If you develop a mild case of thrush after taking antibiotics, eating yogurt or taking over-the-counter acidophilus capsules can help.

Use a soft toothbrush and rinse your mouth with a diluted 3% hydrogen peroxide solution several times a day.

Good control of blood sugar levels in persons with diabetes may clear a thrush infection.

Your doctor may prescribe an antifungal mouthwash (nystatin) or lozenges (clotrimazole) to suck on if you have a severe case of thrush or a weakened immune system. These products are usually used for 5 - 10 days. If they don't work, other medication may be prescribed.

You may need stronger medications, such as fluconazole (Diflucan) or itraconazole (Sporanox) if:

• You have a weakened immune system due to HIV or some medicines
• The infection is moderate to severe
• The infection spreads through your body

Expectations (prognosis)

Thrush in infants may be painful, but it is rarely serious. Because of discomfort, it can interfere with eating. If it does not get better on its own within 2 weeks, call your pediatrician.

In adults, thrush that occurs in the mouth can be cured. However, the long-term outlook depends on your immune system and the cause of the immune problem.

Complications

If you have a weakened immune system, Candida can spread throughout your body, causing a widespread (invasive) infection. This might affect your:

• Brain (meningitis)
• Esophagus (esophagitis)
• Eyes (endophthalmitis)
• Heart (endocarditis)
• Joints (arthritis)

Calling your health care provider

Call your doctor if:

• Your infant has had thrush-like sores in the mouth for at least 2 weeks.
• Your infant is eating poorly due to the sores.
• You are a teen or adult with thrush-like sores.
• You have pain or difficulty swallowing.
• You have symptoms of thrush and you are HIV positive, receiving chemotherapy, or you take medications to suppress your immune system.

Prevention

If you get thrush often, your doctor may recommend taking antifungal medication on a regular basis to avoid repeat infections.

If an infant with thrush is breastfeeding, talk to your doctor about ways to prevent future infections, such as an antifungal medication. Sterilize or throw out any pacifiers. For bottle-fed babies with thrush, throw out the nipples and buy new ones as the baby's mouth begins to clear.

To prevent the spread of HIV infection, follow safe sex practices and use precautions when working with blood products.

References

1. Edwards JE Jr. Candida species. In: Mandell GL, Bennett JE, Dolin R, eds. Principles and Practice of Infectious Diseases. 7th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2009:chap 257.
2. Kauffman CA. Candidiasis. In: Goldman L, Schafer AI, eds. Cecil Medicine. 24th ed. Philadelphia, Pa: Saunders Elsevier; 2011:chap 346.

Review Date: 10/6/2012.

Reviewed by: David C. Dugdale, III, MD, Professor of Medicine, Division of General Medicine, Department of Medicine, University of Washington School of Medicine. Jatin M. Vyas, MD, PhD, Assistant Professor in Medicine, Harvard Medical School; Assistant in Medicine, Division of Infectious Disease, Department of Medicine, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M. Health Solutions, Ebix, Inc.