Ask Emily

23 02 2012

Why does our skin break out in a rash with some viral infections like measles or Fifth disease?

These sorts of rashes are technically known as viral exanthems (the word derives from the Greek word “exanthema,” meaning “breaking out”).

The skin responds to infection with a rash for one of three reasons: the infectious agent releases a toxin that causes the rash, the infectious agent damages the skin and causes a rash, or the immune response results in the skin outbreak.

The skin responds in only a few ways to these challenges, although the pattern of the response can vary from virus to virus (bacteria and some other infectious organisms can also trigger a rash).

The response is the body’s attempt to deal with the presence of viral particles that find their way to the epidermis, or skin. In general, the upshot of the immune response is an area of inflammation. Because viruses cause a systemic or body-wide infection, viral rashes often cover much of the body.

Although the basic pathway to the rash is similar among viruses, the specific pattern of the rash can help distinguish the virus involved. For example, Fifth disease, so-named because it was the fifth virus in a series to be identified as causing a rash, produces a “slapped-cheek” ruddy appearance on the face and may cause a lacy, rather flat rash elsewhere on the body.

A measles rash, on the other hand, starts as an eruption of raised or flat spots behind the ears and around the hairline before spreading body-wide.

One thing to recognize is that not every rash is a viral rash or a benign viral rash, although most viral rashes will resolve on their own. Usually, a fever accompanies a viral rash. If a rash develops, you should be aware of the following warning signs that signal a call to your doctor:

  • If you suspect you have shingles. This highly uncomfortable rash tends to trace along the nerve routes under the skin but can spread out from those, as well. Starting antivirals within the first 24 hours may ward off a more intense recurrence or a permanent pain syndrome called postherpetic neuralgia.
  • If you suspect measles. Infection with this highly contagious virus should be reported immediately.
  • What you think is a rash from a severe allergic reaction or a rash that arises coincident with taking a new medication.
  • The rash accompanies a high fever, spreads rapidly, and starts to look like purple bruising. This pattern is indicative of meningitis.
  • Any rash involving a very high fever, pain, dizziness or fainting, difficulty breathing, or a very young child or that is painful.
  • Any rash that you find worrisome, including for reasons of persistence or timing with something such as exposure to infection, a new medication, or new food.

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By Emily Willingham

Image courtesy of HowStuffWorks

Vaccine Fears: What You Can Do

22 08 2011

What’s not to fear directly about vaccines? There’s a needle that someone pokes into your child. Your child screams. You tense up. What’s in there? you wonder. Viral or bacterial bits that, in ways that are mysterious to a non-immunologist, will keep your child well when intuition seems to say they ought to make your child sick.

Needles, screaming, microbial bits…these naturally would make any parent blanch. The number of vaccines has added to the fear for at least a decade, leading to non–evidence-based calls to “spread out” the schedule or reduce the number of vaccinations.

In fact, the evidence supports the schedule as it’s recommended.

The fear of vaccination is not new. Since Edward Jenner and his cowpox inoculation at the turn of the 19th century, people have latched onto the fear of the known—those needles!—and unknown—what’s in those things?

What might be considered the first anti-vaccine cartoon appeared in response to Jenner’s proposed inoculation of cowpox to combat smallpox.

The vision of cows growing out of arms is comical, but the reality of possible side effects from today’s vaccines can lead some parents to keep their children away from the doctor’s office. Indeed, this anxiety has done so since the days of the 19th century anti-vaccination leagues, aligned against the widespread use of Jenner’s smallpox vaccine.

The vaccine wars in those days were just as bitter and divisive as they are today, including an 1885 march in England in which anti-vaccination forces carried a child’s coffin and an effigy of Jenner himself. Today’s most fanatical crusaders against vaccines may not carry coffins or effigies, but death threats against those who promote vaccines for public health are not unknown.

The fact that the vast majority of parents overcame those fears and had their children vaccinated has led to some of the greatest public health successes of the 20th century. Thanks to the willingness of people to participate in vaccination programs, smallpox disappeared and polio became a thing of the past in much of the world. Indeed, people in those eras knew, often from personal experience, what these diseases could do—maim and kill—and the fear of those very real outcomes outweighed fears of the vaccinations.

But today, we’re different. In the United States, most of us under a certain age have never witnessed a death from diphtheria or tetanus or smallpox or measles. We haven’t seen a child drained of life as a rotavirus rapidly depletes the molecules she needs to live. Many of us have not witnessed the sounds of pertussis, the vomiting, the exploding lungs in an agony of infant death. Why? Because of vaccines.

This very success has, ironically, led to the resurgence of fear and misgiving about vaccines. No longer weighed against anxiety of death or disability from disease, the fear of vaccines now aligns against the bright picture of a nation of children largely free of life-threatening illness.

Without the collective memory of days when children played on the playground one day and died the next of vaccine-preventable disease, the calculus of parental fear pits only the side effects of vaccines against the healthy child. Vaccination requires intentional agency—parental agreement—to impose on that healthy child the very small risk that vaccines carry. Some parents simply are not comfortable either with that intentionality or that risk.

Feeding this reluctance is the explosion of Internet sites that warn against vaccines or disseminate incorrect information about them. The Centers for Disease Control and Prevention (CDC) has provided abundant information about vaccines, including a page devoted to countering erroneous information with facts.

This information will not move the fiercest anti-vaccine groups that lump the CDC in with pharmaceutical companies and others in an alleged conspiracy to harm millions via a money-making vaccine industry. However, it certainly helps concerned parents who simply seek to calm fears, weigh evidence, and make an informed decision about choosing vaccines over the life-threatening illness and compromised public health that result when people don’t vaccinate.

Indeed, these threats to public health have grown considerably with recent large outbreaks of measles and pertussis. The growing threat has led to calls for more stringent requirements for childhood vaccines, including dropping exemptions and requiring that all children be vaccinated over parental objections. This tactic likely would increase vaccination rates among children attending school.

But instead of strong-arming parents into having their children vaccinated, what we really need is a two-fold approach to education. First, we need sober, non-sensationalist reporting from the news media about vaccine-related stories, including stories about side effects, research, and court cases. These articles—and their sensational headlines—are in all likelihood among the prime drivers of the rumor mill against vaccines.

Second, when parents read these stories and turn to a medical professional for input, that input must come as part of a two-way communication between the health professional and the parent, not in lecture format or as patronizing. A little, “I understand your concerns because I’ve had them, too, but here’s what I know that gives me confidence in vaccines,” is considerably better than, “Your child has to be vaccinated, or you can get out of my office.”

As centuries of history attest, no efforts will completely eradicate vaccine fears. Motivations fueling anti-vaccine sentiment that go beyond information gaps range from personal economic benefit to a desire to out-expert the experts to the inertia of fear.

But a careful and persistent information campaign and outreach efforts from medical professionals in the trenches may help keep vaccination rates sufficiently high. To ensure adequate rates requires either these efforts or a resurgence of the deadly diseases that have graphically demonstrated the real balance of the threats at issue here.

Which one would we rather have?

By Emily Willingham

Image courtesy of ajc1

Antibiotics Aren’t for Everyone

1 08 2011

The boy who lost interest in the Velveteen Rabbit—what archaic malady did he have again? Scarlet fever, that’s what it was. One of those things, like consumption or ague, that you only read about in old books . . . until recently, when it hit the headlines by killing two children in Hong Kong.

Unless you live there or have connections to there, you might not have thought too much about it, but it’s actually the latest harbinger of a dead-scary public health menace coming our way. Unlike most global menaces, there’s actually a lot we can do about this one.

Scarlet fever is a bacterial infection caused by group A Streptococcus, the same germ that causes strep throat.  It’s not vaccine-preventable, but it’s pretty easily treated with antibiotics, so since those have been around, nobody’s been too afraid of scarlet fever.

The recent deaths were caused by a strep strain that has mutated to be simultaneously more contagious and more antibiotic-resistant than the ones we were used to dealing with.

It’s still vulnerable to good old penicillin, but given how many other types of bacteria have become resistant to penicillin, it could just be a matter of time before we lose our last treatment option. Then, it’d be down to a battle between the bacteria and the infectee’s innate defenses.

How does antibiotic resistance happen, anyway? Say you have an infected ear, teeming with all manner of bacteria. You take your first dose of erythromycin (or whatever) and, bam, a whole bunch of the least-hardy bacteria go squealing off into the Great Petri Dish in the Sky. Your second dose takes out the next-wimpiest ones, and so on for four or five days. By then, you’re feeling much better, because there aren’t too many bacteria left to inflame your poor eardrum. So you stop taking the erythromycin, because, hey, why take medicine you don’t need?

Here’s why—those few bacteria left puttering around in your eardrum were the cream of the crop, hardy enough to withstand several days’ worth of antibiotics, and now they’re left with no competition for your delectable ear tissue. They multiply unchecked, and you can bet they’re not going to be content to populate just your ears.

You’ve done a little bit of genetic engineering right there inside your own skull, creating an antibiotic-resistant strain of bacteria that’s going to be a headache (or earache) for anybody who happens to pick it up from you, because throwing erythromycin at these bad boys will just make them snarl and chitter like Gremlins.

Naturally, since creating antibiotic-resistant bacteria is so simple even a child can (and often does) do it, you never know when your next infection will be with somebody else’s home-brewed nasties. Or even those of some random pig! That’s right—livestock get antibiotics too, mostly as a sort of general-purpose illness-preventing measure to grow them as big as they can possibly get.

In fact, 80% of all antibiotics in the U.S. are fed to animals that will themselves become food. It’s not well-documented yet, but researchers suspect resistant bacteria may be carried in the critters we eat.

We owe it to ourselves and those around us to understand how this works and how big a deal it is. Patients still end up getting antibiotics for colds and flu-like illnesses—viral infections which antibiotics cannot cure—possibly because their doctors aren’t current on when it’s appropriate to prescribe them.

Probably the biggest example of the pickle this has put us in is the emergence of methicillin-resistant Staphylococcus aureus—better known as MRSA—vividly described in the book Superbug.

It’s a tremendous problem in hospitals, which are just now figuring out how to get a handle on it, but is easy to catch in ordinary community settings too.

Science isn’t sitting back waiting to see what happens with this. There is research going on to develop new types of antibiotics, although it may just be a matter of time before these, too, are easily evaded by our tiny attackers.

Other projects are working on using things like nanostructures to kill bugs that antibiotics can’t touch, or creating new compounds specifically to defeat resistance mechanisms.

But antibiotic-resistant bacteria are in the here and now, so for today, here’s what each of us can do to minimize risks:

  • Get smart about antibiotics. Don’t pressure doctors to prescribe them. If they’re really necessary, take the whole course as prescribed.
  • Consider putting our purchasing power behind meat from animals raised without antibiotics.
  • When in the hospital, we must be that persnickety patient who insists everyone wash his or her hands before touching us.

Bacteria may outnumber us and reproduce faster, but we may yet outsmart them for good.

By Ms. Health Department

Image courtesy of perpetualplum