Merck Manual

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(Candidosis; Moniliasis; Yeast Infection)


Sanjay G. Revankar

, MD, Wayne State University School of Medicine

Last full review/revision Sep 2019| Content last modified Sep 2019
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Candidiasis is infection caused by several species of Candida, especially Candida albicans.

  • The most common type of candidiasis is a superficial infection of the mouth, vagina, or skin that causes white or red patches and itching, irritation, or both.

  • People whose immune system is weakened may have serious infections of the esophagus and other internal organs.

  • A sample of infected material is examined under a microscope and sent for culture.

  • Antifungal drugs may be applied directly to the affected area or taken by mouth, but serious infections require drugs given by vein.

Candida is normally present on the skin, in the intestinal tract, and, in women, in the genital area. Usually, Candida in these areas does not cause problems. However, the fungi sometimes cause skin infections, mouth infections (affecting the mucous membranes), or infections of the vagina. Such infections can develop in people with a healthy immune system, but they are more common or persistent in people with diabetes, cancer, or AIDS and in pregnant women. Candidiasis of the mouth and esophagus are common among people with AIDS. Candidiasis is also common among people who are taking antibiotics because the antibiotics kill the bacteria that normally live in the body and compete with Candida, allowing Candida to grow unchecked.

Candidiasis is bothersome but rarely life threatening. However, some forms of candidiasis are serious. They include

  • Invasive candidiasis

  • Candidemia (the most common form of invasive candidiasis)

In invasive candidiasis, the infection spreads to other parts of the body, such as the heart valves, brain, spleen, kidneys, and eyes. Invasive candidiasis occurs mainly in people with a weakened immune system and in hospitalized people. Candidiasis is one of the most common infections acquired in the hospital.

Candidiasis of the esophagus is one of the illnesses indicating that HIV infection has developed into AIDS (called an AIDS-defining illness).

Candidemia is a serious infection of the bloodstream. In the United States, Candida is a common cause of bloodstream infections. The risk of developing this infection is increased by certain conditions, such as the following:

  • Major surgery

  • Use of intravenous lines or tubes—particularly a tube inserted into one of the large veins of the neck, upper chest, or groin (central venous catheter) or a tube used to provide nutrition (intravenous feeding)

  • Use of certain antibiotics

Candidemia is often fatal if not promptly treated.


Infection of the mouth (thrush) causes the following:

  • Creamy, white, painful patches inside the mouth

  • Cracking at the corners of the mouth (cheilitis)

  • A red, painful, smooth tongue

Candidiasis of the Mouth

Patches in the esophagus cause pain during swallowing.

When the skin is infected, a burning rash develops. Some types of diaper rash are caused by Candida.

If the infection spreads to other parts of the body, it is more serious. It can cause fever, a heart murmur, enlargement of the spleen, dangerously low blood pressure (shock), and decreased urine production. An infection of the retina and inner parts of the eye can cause blindness. If the infection is severe, several organs may stop functioning, and death can occur.


  • Examination and sometimes culture of a sample of infected tissue

  • Sometimes blood tests

Many candidal infections are apparent from the symptoms alone.

To confirm the diagnosis, a doctor must identify the fungi in a sample viewed under a microscope. Samples of blood or other infected tissues may be sent to a laboratory to be cultured and examined to identify the fungi.

Doctors may do a blood test called the T2Candida panel to detect Candida in the blood quickly and accurately. Other tests that detect genetic material in microorganisms may be done, including polymerase chain reaction (PCR). The PCR test is used to produce many copies of a gene from a microorganism, making the microorganism much easier to identify.

If candidemia is diagnosed, doctors may examine the eyes to determine whether the eyes are infected.


  • Antifungal drugs

Candidiasis that occurs only on the skin or in the mouth or vagina can be treated with antifungal drugs (such as clotrimazole and nystatin) that are applied directly to the affected area. A doctor may also prescribe the antifungal drug fluconazole to be taken by mouth.

For infections of the esophagus, doctors prescribe antifungal drugs (such as fluconazole or itraconazole) to be taken by mouth. If these drugs are ineffective or if the infection is severe, other antifungal drugs are used. Choices include anidulafungin, caspofungin, micafungin, or amphotericin B given by vein (intravenously), voriconazole given by mouth or vein, and posaconazole given by mouth.

Candidiasis that has spread throughout the body is usually treated with anidulafungin, caspofungin, or micafungin given intravenously or with fluconazole, which can be given intravenously or by mouth.

Candidiasis is more serious and less responsive to treatment in people with certain disorders, such as diabetes. In people with diabetes, controlling blood sugar levels facilitates cure of the infection.

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