Diagnosis of Candidiasis (Thrush)

By Dr. Ananya Mandal, MDReviewed by April Cashin-Garbutt, MA (Editor)

Candidiasis is more often than not diagnosed on the basis of clinical findings. Symptoms of the condition especially for oral and vaginal thrush may be diagnostic.(1, 2, 3)

Important features that are looked at in the diagnosis of all types of thrush are:-

• the history of previous episodes of thrush, weakened immunity
• weakened immunity
• steroid or antibiotic intake

Diagnosis of Oral Thrush

In diagnosis of oral thrush the appearance of the lesions are characteristic.

To confirm the diagnosis a scraping of the affected areas may be taken and examined under a microscope. An abnormally high number of the yeast is diagnostic.

A culture of the scraping to grow the culprit organism, however, is not diagnostic since Candida normally exists on the body and its presence in the body is not indicative on an infection.

Diagnosis of Vulvovaginal Thrush

In vulvovaginal thrush physical examination alone cannot help diagnose the condition since many other fungal infections mimic Candida infection.

However, a complete gynaecological examination with a speculum is needed. The speculum holds the vagina open for examination.

Usually the diagnosis is made by taking a vaginal secretion sample and examining it under a microscope to see if an abnormally high number of Candida organisms are present.

For this a vaginal swab is taken using a cotton bud. The swab is mixed with a drop of potassium hydroxide and placed over a slide before it is put under a microscope. The yeast shows up.

A culture may not be useful since these organisms are normal inhabitants of the vagina.

The acidity or alkalinity of the vaginal secretions may also help in diagnosis. This is useful in recurring thrush infections. A pH level of 4-4.5 is normal.

Vaginal examination will include palpating and examining other organs like the uterus and ovaries to check for spread of the infection.

Diagnosis of Invasive Candidiasis

Invasive candidiasis is diagnosed with the help of blood culture.

Further Reading

• All Candidiasis Content
• What is Candidiasis (Thrush)?
• Candidiasis (Thrush) Causes
• Candidiasis (Thrush) Symptoms
• Candidiasis (Thrush) Treatment