Thrush

What is it?

"Thrush" is another word for a yeast infection, usually of the mouth in babies, or of the vagina in girls and women after puberty. This Aftercare Instruction is only about thrush in babies – please read our Aftercare Instruction on Vaginitis to learn about vaginal thrush. Yeast is a very common germ in the family of fungi (like mold and mushrooms). All humans have yeast cells living on their skin surface, but it does not grow well there. Like all the fungi, yeast grows best in warm, dark, moist places, on or near the surface. This makes the inside of the mouth an excellent place for yeast to grow. Older children and adults with normal immune systems can fight the yeast well enough to keep it from starting to grow in their mouths. Young babies, though, haven’t developed their immunity very well yet, so yeast takes every opportunity to start to grow. "Thrush" is the word we use for the visible patches of whitish material that forms on a baby’s tongue and the lining of the mouth when the yeast starts to grow.

Thrush is a common problem in infants. It can be triggered by having a cold or other infection that lowers the baby’s immunity for a short time. Babies who have recently taken antibiotics can also develop thrush because the antibiotics kill some of the helpful bacteria that normally control yeast. Usually, however, thrush seems to just sort of appear out of nowhere. Because the yeast causes irritation and inflammation, the areas where it grows become somewhat red and painful. Babies with mild thrush may not seem to notice anything, but babies with moderate or severe infections are fussy and have obvious large areas of white material in their mouths. They tend to feed poorly, not because of a poor appetite but because their mouths hurt.

Thrush is not dangerous by itself, and it is easy to treat. The biggest concern until it is under control, however, is to be sure the baby is getting enough milk or formula for nutrition and to prevent dehydration. Babies with severe thrush can have so much pain that they stop feeding, and can become dehydrated. A separate concern arises in a baby or a child older than a year of age. Children above this age normally have a healthy immune system, and can fight the thrush before it grows. Thrush in the mouth of a child over one year of age is concerning because it can mean that the child’s immune system is working badly.

It is easy to treat thrush, but a little harder to keep it from coming back, or from spreading. Your doctor will prescribe an anti-fungal drug such as nystatin (Mycostatin® and others) to use in the baby’s mouth. These medicines are of the kind called "suspensions," so be sure to shake the bottle well before each dose. Most doctors recommend a dose of about one cc (one ml), to rub around the inside of the baby’s mouth and on the tongue. This medicine only works well right on the thrush – it is not an oral medicine. While it won’t hurt your baby if s/he swallows it, the medicine won’t do any good unless it sits on the thrush itself for at least a few minutes. Often the best way to apply this medicine is to put the measured dose in the baby’s mouth and then use a clean finger tip to spread it around in the mouth. Please be sure to cut your fingernail before you try this, and be sure to wash your hands thoroughly immediately after. Most doctors recommend continuing the treatment until a few days after the last visible trace of thrush is gone.

In some cases, doctors may prescribe an oral medication called fluconazole (Diflucan®, Nizoral® and others). Your baby should actually swallow these medications, as opposed to nystatin, which you only apply in the mouth as a topical drug. Please be very sure that you know which medication your doctor is giving you, and how you should use it.

In order to keep the thrush from coming back, be sure to sterilize or replace all items that you use in the baby’s mouth, such as nipples and pacifiers. The yeast germ can live for quite some time on these objects, and they can easily re-infect the baby. Because oral thrush often leads to a yeast diaper rash, many doctors routinely prescribe an antifungal ointment for the diaper area whenever they treat oral thrush. Please use that medication as directed. You may want to read our Aftercare Instruction on Diaper Rash.

Yeast infections are annoying but rarely dangerous. The biggest risk is dehydration, especially in a very young baby or one with a very severe case of thrush. Here are some things to look out for:

• Fever – thrush itself does not cause a fever
• Signs of dehydration:
• Sunken appearance of the eyes
• Dry tongue and mouth (dry lips are common and are not a sign of dehydration)
• A sunken fontanel (soft spot) in an infant
• Less than normal urination, or dark or strong-smelling urine
• Being too sleepy (lethargic) or being very irritable or fussy
• Cold, pale hands and feet even if the room is warm
• Thrush that is getting worse or not getting better after at least 72 hours of treatment

As we mentioned, babies with thrush in their mouths often get a yeast diaper rash as well, and vice versa. While it’s hard to prevent that from happening, it’s at least a good idea to pay special attention to keeping the baby’s diaper changed and dry, to avoid conditions that would help the yeast grow. Also, please remember that yeast infections can be very serious for people with weak immune systems, such as those with cancer or on certain kinds of drugs. People with those kinds of conditions should not have direct contact with your baby (holding, kissing, etc) until the thrush has cleared up.

Thrush is common and quite normal in younger babies. If a child older than a year develops thrush, however, this can be a sign that something is weakening the child’s immune system. Please check with your doctor if your toddler or older child develops thrush. Both babies and older children sometimes develop thrush as a result of taking antibiotics. Please be sure to discuss this with your doctor – often it’s fine to stop the antibiotic a few days early if that helps the yeast infection to clear up. Please don’t make any changes in your child’s medication without discussing it with your doctor, though.

Caring for a child with thrush can be tiring and frustrating. As badly as you feel for your child, you yourself may feel out of control, inadequate, or even angry – these are normal feelings. Babies and children who have thrush are often fussy and irritable, and parents often feel stressed to the breaking point, especially when there are other children or adults to take care of. One of the best things you can do for your child is to be sure you take care of yourself. If possible, try to have other adults take care of your child for an hour or two each day so you can get some rest or just some quiet time. If you get so stressed that you are worried about your baby’s safety, call your local Parents’ Anonymous Hotline or visit the Parents Anonymous website to find a group near you.