Just in time for summer, I thought I'd offer some pointers on parasites.
Of course, parasites exist year round. But as the weather gets warmer and our patients head outside to play in the dirt or splash around in the toddler pool, the possibility that they'll pick up one of the following five organisms increases.
Here they are in approximate order of the frequency that we see them in central Kentucky:
▸ Pinworms. By far the most common parasite seen in preschool children, the diagnosis is usually made by a parent who finds a little wriggling rice-sized creature in the child's diaper, underwear, or bedding. Treatment—liquid mebendazole or chewable pyrantel pamoate—is given once, then repeated about 10–14 days later.
Families should be advised to wash all bed linens in hot water to get rid of any residual eggs and to prevent reinfestation.
If the problem recurs, retreat the child and consider treating the whole family and the child's playmates. If the parent reports a third sighting after two rounds of treatment, I will ask that they actually bring the worm in.
Some parents become so excessively concerned that they misinterpret many things as pinworms. It's been quite interesting—I've seen husks of corn, pea shells, and little bits of mucus that aren't even organisms.
Once, we got back a housefly larvae from a child's stool. I'm not sure how it got there.
We've also seen the proglottid of a tapeworm—these often fold up on themselves, and can almost look like a pinworm. That child had been treated several times for pinworms before referral.
Another pinworm-related problem is that the child may continue to experience perianal or vulvar itching and continue to scratch even after the pinworms are eradicated. Sitz baths may be helpful in easing the irritation. If itching continues, applying 1% hydrocortisone cream to the area for no more than 1 week can often break the itch-scratch cycle.
Pinworms are often an emotional issue for families. It's important to convince parents that it's not because they or their child is dirty, but, rather, that they picked up pinworms from their friends. To diffuse the worry, I often tell parents that the upside of pinworms is that their child likely has good social skills.
▸ Giardia. Toddler pools are a frequent yet underrecognized source of giardia, which are more familiarly associated with food-borne outbreaks or with transmission via fresh water, such as mountain springs.
But “kiddy pools” in the backyard or even at professionally maintained pool complexes are a particularly likely source of giardia transmission. Because they're shallow, sunlight can degrade the chlorine to below the giardia-inhibiting levels, which are higher than needed for coliforms.
If you see more than one giardia patient from the same swim club or backyard pool, advise the swim club pool staff or pool owners to make sure the chlorine level is being monitored more often. We had a giardia outbreak in an upscale country club's pool, and the parents were mortified. Acquisition of giardia in the pool is likely due to other toddlers using the pool in diapers.
Giardia typically presents with diarrhea, cramps, an extreme amount of flatulence, and stools with a characteristic green bubbly appearance. Once you've seen a giardia stool, you will know it again. The diagnosis is made with a routine laboratory ova and parasite screen.
Furazolidone is the treatment of choice, but metronidazole also works. Of course, these are two of the worst-tasting medicines around. You might advise parents to try chasing it with a spoonful of Hershey's syrup. In older kids, a Hershey's Kiss works. No, I receive no funding from Hershey's.
▸ Ascaris. In a typical scenario with ascaris, the parent reports finding a 2- to 4-inch long “fishing worm” in the child's diaper. This is the easy diagnosis.
However, we had a case last year of a 4-year-old who had been diagnosed with asthma and who continued wheezing over an 8-month period despite all the usual asthma medications including a couple rounds of steroids. He had eosinophilia, which had been attributed to allergies.
As it turned out, this child did not have asthma at all, but rather a classic case of Loeffler's pneumonia, in which the ascaris larvae had migrated to his lungs, triggering eosinophilia and an asthma-like picture. We treated the child with mebendazole twice a day for 3 days, and both the wheezing and the eosinophilia disappeared. The child didn't wheeze thereafter.
Ascaris was far more common in years past. These days we've become such a clean society we just don't see it as much as we used to and it's dropped off the radar screen. Yet, in addition to the pulmonary case, we've actually had two more classical ascaris cases just in the last month—one was spotted by the mother in the child's diaper, the other in the toilet.