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Column originally published Dec 2, 1998

Oral Thrush Can Be Difficult To Treat

Question: I am nursing our two-month-old daughter. She has thrush in her mouth since two weeks of age, and we have not been able to get rid of it. We have tried Nystatin drops in her mouth, applying it by cotton swab, and used Gentian violet. Nothing seems to work. I am getting frustrated. Nursing has been rather painful sometimes. I am getting to my wit’s end. Do you have any suggestion?

Answer:

Thrush in the mouth is a very common problem in young infants. Some research estimated that about 10 percent of infants will develop oral thrush in the first few months of life.

Oral thrush is due to an infection by a yeast (fungus) called Candida. This yeast is present in small quantities in most people and does not cause illness. Infection by Candida in the vagina can happen in as many as 30 percent of women. Much of the time, the infection is so mild that there is no symptom at all. Therefore, many women can carry Canada inside without knowing of its presence.

When babies are born through the birth canal, they often swallow some fluid from their mothers’ vagina. If Candida is present in significant number in the vagina, the baby can get some of the yeast inside the mouth and stomach. We still do not understand exactly what leads to infection in some infants but not others. One factor can be the amount of Candida that is present in the mother’s vagina.

If an infant receives antibiotics after birth, the medicine can eliminate normal healthy bacteria from the mouth, therefore allowing Candida to grow in much larger numbers and lead to infection. This is one of the reasons why we don’t recommend antibiotics to young children, unless if there is a bacterial infection.

Once the infection is present, usually in the form of white patches inside the mouth, it will not go away unless there is effective treatment.

It is very important to distinguish between oral thrush and milk staining in the mouth. After nursing or drinking milk from a bottle, some of the milk will stay inside the baby’s mouth, and this may appear as a whitish stain on the tongue. If one wipes the tongue with a little towel, milk stain can be removed easily, but the patches of oral thrush will stay cannot be removed that way.

Most of the time, Candida infection does not cause too much of a problem, although the child may not nurse as well, or become more irritable. The infection, however, can cause more trouble for the mother. Candida can be transmitted from the baby’s mouth onto the mother’s breasts, and cause an infection that is not very obvious by examination. Many mothers can experience sharp pain inside the breasts, without any sign of infection like swelling or redness. As a result, physicians examining these women may mistakenly think there is nothing wrong, and cannot help them effectively.

The most common treatment for oral thrush is a medicine called Nystatin. It comes in drops and is easy to give. It has a rather bad taste, but most infants can take it without problem. Nystatin works by direct contact, and it is not absorbed very much into the body. It is safe and has very little side effect. Most of the time this treatment is effective. Within a few days the thrush will disappear. Treatment is usually recommended until there is no more white spot present inside the mouth, and then continue to use it for another two days to make sure that all the Candida is gone.

Once in a while, we encounter treatment failure. There are many reasons for this to happen. The most common one is too short a course of medicine, before the yeast is completely eradicated.

Another common cause is re-infection. Anything that goes into the child’s mouth can be covered with yeast. When this object is put in the mouth again, the yeast can be re-introduced, leading to re-infection.

The most common object is the baby soother. I always tell parents to buy several soothers, and make sure that they are boiled after being used for two to four hours. This is to make sure that soothers are sterilized often enough to prevent putting Candida back into the baby’s mouth.

This will also apply to the nipples of the bottles if the baby is on formula feeding. The bottles and nipples need to be sterilized by boiling to kill germs like Candida.

For nursing mothers, infection of the breast by Candida from the baby’s mouth is a real problem. If this is not looked after properly, it can affect the mother’s ability to continue nursing because of pain. Furthermore, Candida present on the mother’s nipples can also cause re-infection of the baby.

Some physicians have recommended applying anti-fungal cream on the nipples in between nursing, even if the breast is normal and the baby has oral thrush. In this way, the infection is treated in both the baby and the mother.

Gentian violet has been used for the treatment of oral thrush for a very long time. Recently there is a question about the safety of this seemingly harmless medicine. It will stain the mouth and lips (as well as mother’s nipples) purple for days. It is quite effective in most situations.

Once in a while, we encounter children that continue to have infection after all the treatment. In that situation, it is necessary to use newer anti-fungal medicines like ketoconazole and fluconazole. These medications are absorbed from the stomach and then go to the site of infection. They are very effective even for resistant infections. I have to caution here that there is very little experience in the use of these newer medications in young children, that is why we use them only in those who continue to have infection in spite of all other measures.

If the mother is nursing, it is advisable for her to take the medicine also. Treatment is usually very short, some experts even feel that one dose is enough to eradicate Candida. Those women who have liver disease should not take these medications.

If oral thrush continues after these newer medications, then the baby needs investigation to make sure that there is no abnormality in the immune system. Babies with a weak immune system can have persistent or repeated Candida infection in spite of effective treatment.