A bout of thrush when you are breastfeeding can be problematic in many ways. Not only are candida yeast infections often painful and tricky to diagnose, but they can also be remarkably persistent: antifungal medication may appear to alleviate the problem, but not eradicate it completely, or it may clear up one episode of thrush, only for another to appear a short time later.
One reason for the longevity of nipple thrush is the high potential for re-infection. Medication can keep yeast at bay while you are using it, but as soon you stop you become vulnerable to attack again. The most potent reservoir for candida species that your nipple comes into contact with is your baby’s mouth (even symptom-free babies are often carriers1), so ensuring this is treated with an antifungal at the same time as your nipples is essential for effectively combating thrush. It is not the only place spores can gather, however – hands and other objects can easily become colonized too, and whilst washing something that has only been in contact with candida spores for a short time can usually get rid of them2, certain objects are able to host thrush for quite a long period.
Towels and clothing are among the surfaces that are at high risk of habouring candida. A study looking at the length of time fungal spores could exist on a variety of fabrics used in hospitals found that candida survived for an average of 5 days after inoculation, and lasted longer on synthetic materials (polyethylene, polyurethane, spandex, polyester) than cotton or fabrics that were a mixture of natural and synthetic fibers3. Washing fabric can eradicate thrush, but it may need to be at a high temperature: one experiment found that candida spores could survive the wash at 50 degrees Celsius, but not 704 (although it should be noted that this research was conducted some time ago, and modern detergents may be more effective at lower temperatures).
The use of a pacifier is significantly associated with oral thrush in babies, indicating that dummies or soothers may also provide a friendly environment for candida spores1. A study examining the microorganisms prevalent on the surface of pacifiers showed that this was indeed the case. Like teeth and dentures, pacifiers can develop biofilms that play host to a complex array of microorganisms including numerous bacteria and funghi5. Biofilms are pretty persistent: simply ‘sterilizing’ with boiling water will not remove them5,6. It is not impossible to get rid of them, however, and in fact an effective means of doing this can be found in most domestic kitchens. When candida spores are subjected to microwaves for a sufficient length of time, their cell membranes are irreparably damaged, rendering them ‘inactivated’6. Three minutes immersed in water in a 650W microwave is able to eradicate candida from dentures7, and the chances are this is also an effective way of sterilizing pacifiers.
The best way of treating thrush is to take a sufficient course of antifungal medication, but to prevent it returning it is also a good idea to ensure that anything coming into close contact with nipples or mouths (such as towels or pacifiers) is kept free of rogue candida spores. Whilst washing hands in soapy water will generally decontaminate them, this is not necessarily the case for fabric or pacifiers, which can provide a home to yeast spores for some time, even after they have been superficially cleaned. To get rid of candida for good, there are two options: a hot wash or session in a microwave; or throwing everything out and starting again. Whilst the second option may be tempting, it may also prove rather expensive – fortunately the first option should do the job just as well.