What Is Oral Thrush?
Everything You Need to Know about Oral Thrush
December 9, 2022

Everything You Need to Know about Oral Thrush

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Everything You Need to Know about Oral Thrush.
Everything You Need to Know about Oral Thrush

Your baby’s mouth goes through so many changes in the first two years of life that every new difference can seem alarming. Teething, drooling, bumps and falls, different colors of the gums—and their mouths are so tiny! A good rule of thumb when it comes to your baby’s mouth is: if your baby is comfortable and feeding normally, there’s no need to panic.

One fairly common thing you may notice on your baby’s tongue is a white patch. Most of the time it’s just milk. However, if you suspect your baby is uncomfortable during feedings and notice other areas of the mouth with white or yellowish patches, it could be oral thrush.

What is oral thrush?

Oral thrush, also known as Candidiasis, is an infection of the mouth caused by overgrowth of the fungus Candida. Candida, along with millions of bacteria, are always present on our skin and mucosa (the inner lining) of our intestines, mouth and urinary and genital tracts. If Candida starts to grow more than normal, it’s called a fungal or yeast infection. This same fungus Candida is also responsible for vaginal yeast infections and can make diaper rashes worse.

What does oral thrush look like?

In the mouth, thrush can look like white or yellow patches on the tongue, insides of the cheeks, lips and gums. It can also look like a very thick white patch toward the back of the tongue and the normal bumpy texture of the tongue is obscured. If you notice these patches and your baby appears to have pain with eating or sucking, call your pediatrician.

At home, the easiest way to tell the difference between thrush and a milky tongue is by wiping the area with a cloth: thrush will not wipe away easily and may result in redness or bleeding.

What causes oral thrush?

In infants, thrush often occurs when prolonged sucking causes irritation from friction. Thrush typically affects irritated skin and mucosa and does not infect normal, intact skin. For older children, thrush can occur after taking antibiotics or using an inhaler without rinsing with water afterward.

When does thrush go away?

For the most part, oral thrush goes away in two to three weeks without treatment. Eating yogurt or another probiotic can sometimes be enough to help restore the good bacteria and fungal balance. (Keep in mind: Yogurt shouldn’t be given to babies under six months old.) But if the thrush persists after two weeks, recurs or if your baby has discomfort with eating, sucking or swallowing, it’s time to call your child’s doctor or dentist.

Is thrush contagious?

Thrush isn’t generally contagious and doesn’t spread to siblings, friends or other caretakers. However, a breastfeeding parent may notice redness and irritation around their nipples. It’s safe for your child to go to childcare as long as your child is comfortable and feeding normally. It’s important to boil all pacifiers and bottle nipples to clean the fungus from those surfaces and prevent re-infection.

How is oral thrush treated?

For a child without underlying immunity conditions, thrush will resolve on its own in about two to three weeks. If your healthcare provider prescribes a topical antifungal medication, it could still take around one to two weeks to get better. Antifungal medication only works when it’s in contact with the patches, so you’ll need to apply it to your baby’s mouth several times throughout the day, or give lozenges to your older child. If you’re breastfeeding, your child’s doctor may recommend applying a topical antifungal medication to your own nipples as well.

Babies experience so much of the world through their mouths! Getting comfortable checking your baby’s teeth, lifting their lips and looking into their mouth is a valuable part of taking care of your baby, even if they get mad about it sometimes. Once you’re familiar with your child’s mouth, you’ll more easily be able to clue in to whether something is normal or causing discomfort and communicate that with your healthcare team if needed. After all, you know your child the best.


Dr. Kristina Svensson is a board-certified pediatric dentist and mom of three working in clinical practice and teaching in San Francisco. Her mission is to demystify oral health care and provide actionable, evidence-based strategies to reduce your child’s risk for developing cavities. In her free time she enjoys weaving, drawing and making stop motion LEGO videos with her kids. After many years as an over-achieving non-parent, she now firmly believes that practice makes progress (not perfect) and reminds herself on a daily basis that she is a good enough mom.

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