Treating mouth thrush

How do I treat thrush?

Thrush is best treated with 2% miconazole gel. It is applied by cotton swab to the inside of the baby’s cheeks and lips and then to the tongue, using the other side of the swab. This is done 4 times each day after feeds for 10 days. Other options are nystatin liquid, which is not very effective and often gives babies an upset tummy or oral fluconazole, which is very aggressive. Gentian violet may burn the baby’s mouth, among other side-effects, and is not recommended. If your baby has thrush and you have other risk factors for nipple yeast infection, you may want to use miconazole on your nipples and areolas to prevent infection while your baby is being treated.

A) Treating thrush

If your baby has thrush, it should be treated. The main choices are miconazole gel, nystatin liquid, and oral fluconazole (Quindós 2019). We recommend miconazole for its effectiveness and safety. Gentian violet is not recommended.

Please see your health-care providers if your baby has thrush.

B) Miconazole gel

1) Using miconazole gel

Miconazole 2% gel is very effective against thrush (Hoppe 1997; Isham 2010). It is more effective than nystatin (Zhang 2016).

It is not commercially available in Canada, so we have a pharmacy make it up for us. It is available for purchase without a prescription in other countries. 

To treat the baby with miconazole gel:

  1. Start after the baby has breastfed.
  2. Dip a large cotton swab into the gel so that the swab is coated. 
  3. Use this to paint the inside of the baby’s cheeks and lips.
  4. Dip the other end of the cotton swab into the gel.
  5. Use the second end to paint the baby’s tongue.
  6. Do this four times each day.
  7. Continue this for 10 days.

Miconazole works on the tissues it touches and does not need to be swallowed to treat thrush. To minimize the risks of side effects, only use enough gel to coat the areas. Larger amounts may also increase the risk of the baby choking (de Vries 2004).

2) Risks of miconazole gel

Miconazole gel is generally well tolerated (Dhondt 1992). Adults have reported mouth burning, nausea, and diarrhea.

Miconazole is in the same family as fluconazole and can have similar side effects when absorbed through the baby’s gut (Garcia-Cuesta 2014).

C) Other options

1) Nystatin liquid

a) Using nystatin liquid

Nystatin suspension (liquid) is sticky and yellow. It is not all that effective at treating thrush (Goins 2002). One review (Lyu 2016) showed that nystatin liquid cured between 9% and 63% of thrush cases among otherwise healthy babies when used for two weeks. Another study (Blomgren 1998) showed that only 16% of babies were clear of thrush when nystatin liquid was used for three weeks.

The usual recommended dose is two to five millilitres (one-half to one teaspoon) four times each day. 

Nystatin does not enter the baby’s body through the gut. Rather it only treats what it can touch. There is no need to swallow it. Therefore it can be painted on the baby’s mouth using a swab as when using miconazole. This reduces the amount of medication given to the baby and may reduce tummy upset, a common side effect (Lyu 2016). 

If the thrush does not clear up after one week of use, it may be necessary to paint it on the baby’s mouth after each feed.

b) Risks

In addition to tummy upset, nystatin liquid has been reported to cause a rapid heart beat, wheezing, and allergic reactions.

2) Fluconazole oral suspension

a) Use of fluconazole oral suspension 

Fluconazole liquid (oral suspension) can be used to treat oral thrush (Garcia-Cuesta 2014). The dose depends on the baby’s weight (3 mg/kg) and it must be swallowed. It is well tolerated and generally safe and effective (Novelli 1999). It appears to be more effective than nystatin liquid (Goins 2002).  

b) Risks

Fluconazole will enter the baby’s system and can cause the same problems as when mothers use it for treating nipple yeast.

D) Reasons for not using gentian violet

1) Describing gentian violet

Gentian violet (also called crystal violet or hexamethyl pararosaniline chloride) is a bright purple dye.

It has a long history of being used for both bacterial and fungal infections in humans and animals. It can be effective in treating thrush (Padhye 1967).

2) Risks of gentian violet

a) Cancer concerns

While it is easy to obtain and cheap, Health Canada has advised Canadians to stop using it out of concern that it may increase the risk of cancer (HC 2019). The World Health Organization has similar concerns about its cancer-causing risk (WHO 2014). The U.K. and Australia have restricted its use (Drinkwater 1990).

Gentian violet  may affect the baby’s DNA, the building blocks of genes and chromosomes, as it (NLM 2013):

  • Has been shown to interact with the DNA  of cells in numerous ways to promote mutation and cancer in rodents and other animals and in fish (Aidoo 1990; Docampo 1990; Littlefield 1985; Littlefield 1989; Mani 2016; Rosenkrantz 1971).
  • Has a chemical structure (triphenylmethanes) similar to malachite green and brilliant green, both of which can also damage DNA (Oplatowska 2011; Srivastava 2011; Zimina 1990).
  • Has caused liver and thyroid cancer when fed to mice in large amounts.

However, no cases of cancer in humans have been linked to the use of gentian violet (Maley 2013).

b) Side-effects of gentian violet

Gentian violet can (NLM 2003):

  • Burn the baby’s mouth causing painful ulcers that can interfere with feeding (Slotkowski 1966; Utter 1990).
  • Cause allergic reactions of the skin (Pasricha 1982).
  • When swallowed, cause nausea, vomiting, and tummy pain and block the airway (Baca 2001).
  • Burn and damage the eyes if there is accidental contact (Dhir 1982).
  • Be fatal in large amounts.

In addition, gentian violet:

  • Can cause permanent skin staining (tattooing) when used in the mother’s open wounds or transferred there from the baby’s mouth.
  • Is messy and will stain clothing.
  • Persists in the environment for a long time (Mani 2016).

3) Using gentian violet

If used at all, it should only be used in concentrations of less than 0.5%, painted in the baby’s mouth once each day with a swab and for a maximum of seven days (Anderson 2018; Berens 2016).

E) Treating the mother who does not have a nipple yeast infection

If your baby has thrush, you are at a higher risk of getting a nipple yeast infection and may want to prevent it. This is more important if you have other risk factors or have had a previous nipple yeast infection.

In this case, you may also like to use miconazole cream on your nipples and areolas until the baby has finished the thrush medication and thrush is no longer seen in the baby’s mouth. Nipple yeast infection can cause a lot of trouble, so this is not unreasonable. Ensure that you wash your nipples to remove any cream before breastfeeding.

If you already have pain or signs of a nipple yeast infection, it should be treated.


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