Thrush can be a mild infection that causes no symptoms. If symptoms develop, they may include the following.

In infants

Symptoms of thrush in an infant may include:

• White patches inside the mouth and on the tongue that look like cottage cheese or milk curds. Thrush is often mistaken for milk or formula. The patches adhere to the mouth and tongue and cannot be easily wiped away. When rubbed, the patches may bleed.
• A sore mouth and tongue and/or difficulty swallowing.
• Poor appetite. The infant may refuse to eat, which can be mistaken for lack of hunger or poor milk supply. If the infant is unable to eat because of a sore mouth or throat, he or she may act fussy.
• Diaper rash. Diaper rash may develop because the fungus that causes thrush will be in the baby's stool.

In adults

Symptoms of thrush in an adult may include:

• A burning feeling in the mouth and throat (at the start of a thrush infection).
• White patches that adhere to the mouth and tongue. The tissue around the patches may be red, raw, and painful. If rubbed (during tooth brushing, for example), the patches and the tissue of the mouth may bleed easily.
• A bad taste in the mouth or difficulty tasting foods. Some adults say they feel like they have cotton in their mouth.
• Sore, red nipples in a breast-feeding mother. She may also have a severe burning pain in the nipples during and after breast-feeding. Her baby (who spreads thrush to the mother's nipples) may not have any symptoms.