Joseph R. Anticaglia, MD
Medical Advisory Board
Oral Thrush:
1) What Is It?
Oral thrush is a common yeast infection in the mouth of babies and young children. Children are susceptible to this fungal infection since their immune systems are still developing. It’s caused by an overgrowth of Candida albicans, a fungus that’s normally present in the mouth and on the skin.
2) Symptoms
In most newborns, and in the very young, the children may experience mild discomfort, or no symptoms. Others have pain demonstrated by being irritable while eating, or refusing to eat.
The symptoms are due to the odd shaped, curd-like white fungal lesions in the mouth, (that is, on the tongue and inner cheeks), and on the lips. When the lesions are removed, they expose a red undersurface that can bleed. It can cause cracked skin in the corners of the mouth (angular cheilitis)…
A diaper rash can be present because both infections are caused by the overgrowth of the yeast Candida. Look for red, irritated skin in the diaper area.
3) Causes
Thrush is predominately caused by a proliferation of Candida albicans, which can happen after antibiotic use, or inhaled steroid medication when used inappropriately; also, breastfeeding from a mother with a yeast infection, or overuse of a pacifier.
4) Diagnosis
Visual examination of the mouth, and throat with the characteristic lesions is usually enough to make the diagnosis. Occasionally, microscopic examination, or cultures and sensitivity tests are used to confirm the diagnosis.
5) Treatment
Your physician will probably prescribed a topical, anti-yeast (anti-fungal) medication for this problem; and advise not feeding the baby for thirty minutes after applying the medication to the mouth. If there’s a bad diaper rash, it can also be due to yeast. Ask your doctor about an anti-yeast ointment, or cream for the rash.
Wash the pacifiers — bottle nipples and bottles — in the usual way with soap, and hot water. It’s probably a yeast infection if the mother’s nipples are red and sore, and it’s treated with antifungal medications.
6) Complications
Thrush rarely progresses to serious complications. However, thrush can cause irritability, and feeding difficulties which can lead to dehydration, decreased urinary output and fever, which if not quickly recognized and brought to the attention of your pediatrician can have serious consequences.
7) Prevention
Have your child rinse their mouth after using inhaled corticosteroid medication. Ask your doctor about using a spacer on the inhaler. This increases the amount of medication that reaches the lungs and reduces the potential side effects of thrush in the mouth. Be aware of the potential thrush side effects of antibiotic use.
Treat breast feeding mothers, if necessary, for yeast infection. Also, clean, and sterilize bottles, bottle nipples, and pacifiers. Watch for early signs of thrush (oral candidiasis). While not highly contagious, thrush can spread through the baby’s saliva; therefore, wash your hands, and baby’s hands frequently. Watch for early signs of thrush.
8) Associated Medical Conditions
Thrush is basically a local disease that rarely spreads to other parts of the body. However, special attention should be given to premature infants, and immunocompromised children for the possibility of associated medical conditions.
9) When to Call/See Your Doctor?
Call/See your doctor if you think your child needs to be examined; especially if the child is less than two months old. Call/See your doctor if the baby’s symptoms worsens; such as, difficulty feeding, becoming more irritable, drinking, and urinating less than normal, or has a fever.
Oral thrush is a common mouth infection in babies and young children. It rarely spreads to other parts of the body. It can be treated effectively with appropriate antifungal medication and preventive measures. Special attention should be given to premature infants, and immunocompromised children.
References
- American Academy of Pediatrics; Thrush (Candidiasis)—Child Care and Schools; 9/23/24
- Centers for Disease Control and Prevention (CDC): Candidiasis.
- Michelle P. Tellado, MD; Oral Thrush. Kids Health, September 2023
- Joseph R. Anticaglia, MD; Oral Thrush in Adults: Spotlight on Oral Candida Infection; Doctors Column, September 2025
This article is intended solely as a learning experience. Please consult your physician for diagnostic and treatment options.