What do we need to know about hand, foot, and mouth disease?
Isn’t it great that we have a disease whose name perfectly describes it? It makes things a lot simpler than trying to remember some syndrome named after an obscure Lithuanian pathologist.
This is something that most of us have seen, experienced, or at least heard of, so let’s consider the most important points we should all know. Hand, foot, and mouth disease (HFMD) was only described a few decades ago—1957—though the virus that causes it has been around for much longer than that. This is one of the Coxsackie viruses, a group that’s capable of causing a wide range of infections in humans. This particular organism—an enterovirus—causes an infection after being orally ingested from either the GI tract or through upper respiratory secretions—the coughs and sneezes of an infected individual.
A cough is one thing, but the GI tract?
That’s right, the virus is ingested after we come into contact with infected fecal material. We know—that’s pretty gross. But that’s how it happens. Changing your child’s dirty diaper is an opportunity just waiting to happen. What makes this important is that this virus is very stable outside of the body. It can remain active and infectious for significant periods of time on a changing table, bed clothes, or just about anywhere. Hence the need to clean and disinfect potentially contaminated areas.
Once ingested, the virus replicates in the GI tract and then spreads throughout the body. With HFMD, the incubation time from exposure to the appearance of the skin and mouth lesions is usually three to five days, but can be up to one week. What makes this infection so difficult to contain is that a significant percentage of children can become infected but never have the rash. They can shed virus through their GI tract for two or three months, and through their respiratory tract for four weeks. This shedding can result in transmission to other children, who then can manifest the full-blown disease.
We expect to see this infection in late summer and early fall, and in children, particularly those younger than five to seven years of age. However, it can occur throughout the year and in any age group.
Now, what does HFMD look like? Let’s start with the hands and feet. Typically, you’ll see multiple raised, red, or blister-like lesions on the soles of the feet and backs of the toes, and the palms of the hand and backs of the fingers. These are usually small—up to a quarter of an inch—but can be larger. And while the hands and feet are most often involved, the rash can appear on the legs, buttocks (frequently infants and young children), and even the face. These lesions don’t itch and usually aren’t painful. Most are gone in three to four days.
The oral lesions look much the same, and are generally found on the tongue and inside of the cheeks. The blisters can be surrounded by a thin, red halo, and are about the same size as the skin lesions. With some types of this virus, these can be painful, and make eating and drinking difficult, especially with small children.
Here’s the tricky part. While about seventy-five percent of patients have both the skin and mouth lesions, the other twenty-five percent only have one or the other. The diagnosis is made by the appearance of the rash and what’s out there in the community. When HFMD is going through daycares, schools, or any place where people gather, there will be a lot of infections.
In addition to the mouth and skin lesions and sore throat, we only expect to see a low-grade temperature (less than 101F) and not much else. This is almost always a benign and short-term problem. We worry when a child develops a fever that persists for more than three days, starts vomiting or won’t eat or drink due to the painful mouth lesions (posing a significant risk of dehydration), or becomes lethargic. Those things need to be evaluated.
But what about treatment? Can’t you do something?
The best care is supportive. Plenty of fluids, ibuprofen or acetaminophen for pain/fever, and rest. Antibiotics won’t do any good, and there is no anti-viral medication that is effective. The good news is that in the vast majority of those infected, HFMD is a nonthreatening process and resolves in a few days. It’s very contagious, and that’s something to keep in mind. While we’re not completely sure, it appears that children are infectious for less than a week after the rash disappears. So wash your hands, keep your fingers out of your mouth, and disinfect that changing table!
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