Baby, What’s the Thrush? Oral Rashes in Infants

Thrush sounds like a nice thing to have, doesn’t it? Evocative of a perched, nimble songbird, thrush refers in medicine and lore to the overgrowth of a ubiquitous yeast, Candida Albicans, along the linings of the oral cavity. Ptooey!

“What is up with my milk?” Many new moms will ask, most often during a routine visit in the first months of life, “It seems to get stuck on my baby’s tongue and I can’t get it off.” Instead of telling them that adherent white plaque on the tongue, cheek or lip is a byproduct of infectious yeast, dead cells, proteins, and rafts of bacteria, I’ll say: “That’s thrush.”

From there, we talk about bit more about what it is. Defusing freakouts is always better.

In healthy children, thrush peaks in incidence around the first month or two of life, and happens frequently up to about 9 months–over a third of infants will be affected at some point . Toddlers and older children may experience bouts of thrush following the use of antibiotics, inhaled steroids for asthma, or for children and adults on chemotherapy or with immune disorders.

Parents–particularly first time parents– who have been applying Purell to every noun in their infant’s vicinity are often astounded that this abomination occurred on their watch. Where’d it come from? How could they have prevented such a thing? Is their child sick? Fortunately, the biology exonerates us all, but it is helpful to explain. The human mouth is a harmonious place, normally, and the ecosystem of bacteria that live there generally don’t cause trouble. In newborns and younger infants (or for the kids noted above), the oral cavity exists as the host’s immune system is booting up to full strength, and good ol’ opportunistic Candida is very happy to move in, crowd out the local microflora, and set up shop, thanks very much.

Infants can become colonized by Candida yeast as they pass through the birth canal and pretty much at any time once they enter the world. Most babies are exposed, and nothing happens. Candida albicans yeast is all over the environment, and caregivers can unwittingly pass it onto babies by their hands or body contact, including via nipples when breastfeeding. Please: don’t stop kissing your baby! For any family, basic handwashing is probably the best preventive action one can do. Again, we don’t point yeasty fingers at each other in blame. Rather, let’s go to the next key question: Does it hurt?

The impact of thrush on affected infants and kids varies greatly, and in my experience, the size of the rash seems to have no connection to how bad or benign a bout of thrush can be. I have seen children with mouths that appear lined with cotton seem unawares, while other children with small plaques demonstrate clear discomfort. Most infants with thrush are not symptomatic, and they act and feed normally. Some babies will ‘go off their feed,’ pulling away from the breast or bottle to cry, or feeding in smaller bursts, more often. Older children and adults who can describe their experience relate that their infections of thrush can be most unpleasant, including sensations of burning, or sharp, searing oral pains.

Consequently, thrush is high on the list of potential problems–our so-called differential diagnosis–of any young infant who doesn’t appear to be feeding well. Thrush can be the root cause of parents coming in for a sick visit, and just as often, it is something we stumble upon as the primary care provider takes a history and examines the patient. We do well to keep our eyes and ears as open as those little mouths. Thrush is a visual diagnosis. The clinician may get a cotton tip swab and rub a collection of material on an infant’s cheek or tongue. If the gunk comes off, it is most likely residue of milk or a recent spit up. If the plaque doesn’t come away, then we think thrush. Bingo.

Before we go to talk of treatment, however, we need to look further. Oral colonies of Candida Albicans frequently (and some would say, mischieviously) can pass through the gut and cause a distinctive diaper rash. Candidal diaper dermatitis (a term that would almost be a good name for a rock band) erupts in red patches and bumps along the bottom and nether bits. Pediatricians are trained to look for scattered ‘satellite lesions,’ or bumplets that occur like splatted paint outside the main part of the rash. In most cases, it pays to be overcautious, and treat the babies at both ends if thrush and a diaper rash are found. Treatment, we will learn, is as much about eradicating the yeast as it is preventing a cycle of re-infection.

Of note here: Candida does cause more substantial, aggressive and potentially devastating infections. Candidal infections of the esophagus, for example, are a scourge for patients on chemotherapy, or being treated for HIV. For the purposes of primary care pediatrics, however, I’ll focus principally on the littluns with oral infections, and presumably healthy ones at that.

Treatment for thrush usually works, but it can take awhile, and be a bit frustrating. Conventional medical wisdom describes thrush as a self-limited illness, and as such, could (theoretically) go away on its own. I believe this is rarely, if ever the case, and that candidal infections in kids should be treated. Primary care providers usually go to Nystatin as first line for babies. Nystatin must be applied three or more times a day, best done in babies when swabbed with a q-tip along the lining of the mouth (be careful not to gag, junior here! Gentle, folks!). Resistance is uncommon, but it can take up to a week before parents start to see the retreat of the plaques, and up to three weeks before the infection is gone. That’s a long time! Gentian Violet is another, less popular option for thrush. This over the counter solution does work and takes just about as long as Nystatin to take effect,. But is no better in my estimation. Most families loathe the stuff, and the violaceous hues it imparts to skin, clothing, and just about anything else it touches. For suspected resistant cases, docs may go to an oral antifungal medication–a bigger gun, to be sure, but it usually puts things right. For any family, I suggest they talk to their primary care doc about what works best for them.

For breastfeeding moms and children, the clinician must consider treatment of the infant and the mother. Even on medication, a child can leave invisible but active bits of Candida on mom’s breast, effectively re-innoculating themselves at subsequent feeds. Like many caregivers, I’ll prescribe a medication for the baby, and will give a Nystatin-containing cream for the mother. I instruct moms to apply the stuff a couple of times a day, wiping their breast and nipples with a clean cloth before the baby’s next meal.

But, wait–as they say on late night infomercials– that’s not all! Parents and clinicians need to get holistic with thrush, preventing that dreaded re-infection. Families need to remain vigilant, and to consider Nystatin creams or ointments to potential candidal diaper rashes. And, for awhile and until the thrush is gone, I advise parents to boil pacifiers, bottle nipples, or teething toys for 10 minutes after use by the baby. That is harder than it sounds, but is necessary. With consistent effort, most families see babies do just fine and make a full and speedy recovery.

If parents ever felt that oral thrush was progressing on therapy, or if their child was refusing to feed , appeared inconsolable or great discomfort, I recommend they contact their child’s primary care provider and check in.

In the meantime, bon appetite to those bottle or breast feeding infants! Snap a photo when the newborn gives one of those squinty yawns! Kiss and hug and hold them while they are dear and wee and precious. And, every once in a while, peek in their mouths for those cottony white patches. If you see them, don’t panic. You can do something about it. Check daily, at the same appointed time, even. That’d make it “Thrush Hour”, no?

(photo above by diana and bart willem; cartoon below by me)

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