After baby's antibiotics, a case of oral thrush

Kids are pretty resilient, which makes them ideal patients. Case in point: the 3-month-old seen for a hospital follow-up visit. The infant had been recently diagnosed and treated for a type of bacteremia, or bacterial blood infection. She was, however, not going to let all that get her down, coming into the office smiling and cooing and looking none the worse for wear.

The only thing that stood out on her exam was the presence of thick white plaques coating her inner cheeks. The material did not easily scrape off when a tongue blade was stroked along the inside of her mouth, and instead of removing the white lesions, this maneuver just seemed to make the areas look red and irritated. The classic look of the mouth lesions, coupled with the fact that the child had just finished a long round of IV and oral antibiotics, made the diagnosis rather clear-cut.

It could be none other than a case of thrush, the common oral fungal infection familiar to many parents and grandparents. Thrush is a diagnosis that is relatively easy to explain, as a number of moms have already had some past experience with their own uncomfortable versions of yeast infections following antibiotic therapy.

Antibiotics perform a vital function as they combat serious bacterial infections, but they are not particularly discriminating fighters. Antibiotics can kill many types of bacteria on their way to eliminating the real perpetrator organism. When the bacteria we peacefully coexist with, also known as our "normal flora," are temporarily wiped out, yeast can overgrow, resulting in conditions such as oral thrush, candidal diaper rashes and vaginal yeast infections.

In their 2007 Pediatrics in Review article titled "Oral Conditions," Drs. David Krol and Martha Keels report that about 2 percent to 5 percent of healthy newborns develop thrush, with the majority of cases caused by the fungus Candida. While Candida can just "hang out" in the normal human mouth and throat, if a baby's defenses are down, the fungus can spread and cause the disease process known as thrush.

Krol and Keels note that a child's natural defenses may be weakened by an immature immune system (as in early infancy), an immunocompromised state (as in HIV or diabetes), use of certain suppressive medications (such as chemotherapy or inhaled steroids), conditions that result in decreased salivary flow, states of poor oral hygiene, as well as the previously mentioned use of antibiotic therapy.

While oral thrush is generally benign and fairly common in the first six months of life, the two pediatric researchers suggest an immune work-up for children older than six months who experience thrush with no obvious cause, or thrush that persists despite adequate treatment.

Infants with oral thrush can be asymptomatic and happy, but parents often describe a child who is fussier than usual and appears uncomfortable while sucking for breast or bottle feedings. Thrush treatment involves application of a prescription antifungal agent to the mouth. In more stubborn cases, the child can be given an oral antifungal medication such as fluconazole, the liquid version of the pill commonly used to treat women's vaginal yeast infections. Unlike the single pill dosing for adult women, therapy for younger children can extend over several weeks.

When you see thrush in an infant's mouth, look for diaper rash as well, since the two conditions often go hand-in-hand. Fungal or candidal diaper rashes appear as clusters of bumpy pink skin lesions, and generally respond well to over-the-counter antifungal creams.

Thrush can be tricky to treat and can recur, as when a breast-feeding mom is dealing with her own yeast-infected nipples. Since mom and baby often pass the fungus back and forth, if baby is developing white mouth lesions and mom has sore, red nipples, it's a good idea for the pediatrician and the gynecologist to treat both parties simultaneously.

Careful cleansing of all artificial nipples such as pacifiers and bottle nipples should be done to avoid reinfecting the infant during the course of treatment. Washing in soap and water after each use and running all of the rubber nipples through a hot, top rack dishwasher cycle at the end of the day usually does the trick. In persistent cases of thrush, old nipples and pacifiers may need to be discarded.

• Dr. Helen Minciotti is a mother of five and a pediatrician with a practice in Schaumburg. She formerly chaired the Department of Pediatrics at Northwest Community Hospital in Arlington Heights.