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 stick 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, which may develop because the yeast that causes thrush also 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 stick 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.

A breast-feeding mother may get a yeast infection of her nipples if her baby has thrush. This can cause sore, red nipples. She may also have a severe burning pain in the nipples during and after breast-feeding. But her baby may not have any symptoms.