Ask Emily

29 03 2012

Why does our hair thin out as we age? My aunt lost hair in unexpected places as she closed in on her 80th year.

The reasons for hair thinning as we age range from benign but perhaps unwanted processes to serious disease. One reason your hair may seem thinner as you get older is that each individual hair is itself literally thinner because the hair follicle narrows with age. The result is hair with less volume than you may have had before, which seems like thinning. Because thinner also means “breaks more easily,” you may see more hair in your hairbrush or after a shower, but that doesn’t mean your hair is actually falling out.

If your hair is really falling out, the usual cause is an inherited susceptibility to androgens. The official name is androgenetic alopecia (“androgenetic” refers to an inherited susceptibility to androgenic hormones and “alopecia” means hair loss). Most people are aware that men develop this form of hair loss, which we know of more colloquially as “male pattern baldness.” Men and women exhibit different patterns of baldness when these androgens kick in with age, and women tend to lose their hair over the front part of the scalp and have thinning all over. This loss in women also may be related to changes at menopause, and some research suggests that estrogen decline in addition to androgen activity could be involved. A recent study also found that malfunctions in the source cells for hair follicles may also be part of the pathway that leads to androgenetic alopecia.

While the loss itself is not harmful, the appearance that results can be particularly difficult for women, as most people don’t expect it to happen in women, in spite of how common it is. Treatments for androgenetic alopecia in women include use of compounds that block androgens or a compound called minoxidil that circumvents androgen activity and promotes hair growth.

While these common causes of hair thinning are relatively benign in health terms, thinning can also signal something more dire. One common health-related cause of hair loss is thyroid dysfunction. Emotional or physical stress, such as childbirth, major surgery, or severe infection can also elicit a widespread loss of hair weeks or even months after the episode occurs. The loss eventually slows.

Some infectious diseases can cause hair loss, including syphilis, while autoimmune diseases like lupus can also be to blame, although some forms of lupus and associated hair loss may actually improve with age and after menopause. In elderly women, causes of hair loss include pulling out the hair themselves in some cases, known as trichotillomania. Another potential cause of hair loss is giant cell arteritis, which is inflammation of the arteries in the upper body, head, and neck. If a person whose hair is thinning also has been diagnosed with cancer, any hair loss should be closely investigated for the possibility that the cancer has metastasized or migrated to the scalp.

The bottom line with hair loss is that any hair loss that is sudden, occurs in an odd pattern, or that you simply find worrisome justifies a call to a medical professional. As one scientific abstract noted, hair loss particularly in postmenopausal women “warrants close inspection.”

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By Emily Willingham

Image courtesy of  Wikimedia Commons

Ask Emily

27 10 2011

I got a flu vaccine one year and ended up getting the flu anyway. Doesn’t that mean the vaccine doesn’t work?

Influenza viruses are notorious for constantly changing. Making vaccines against them is also notoriously difficult because it requires several months of advance preparation before the viral doses can be ready.

If you’ve heard of “bird flu,” you may realize that flu viruses flourish pretty well in the bird-related environment, and vaccine developers grow their viruses within fertilized chicken eggs (that’s why you’ll be asked if you’re allergic to egg proteins). Every vaccine requires about three eggs to yield sufficient (killed) virus, which translates into millions of chicken eggs (i.e., making 300 million vaccine doses would require 900 million eggs).

It also translates into six months of lead time for producing the viruses required to make the vaccine. To find out more about the current year’s strain selection, visit the Centers for Disease Control and Prevention site, which offer comprehensive information about influenza vaccines.

That advanced lead time means a delay between growing the viral strains authorities have determined may be most prevalent in the upcoming flu season and the actual arrival of the current season’s viruses. Experts can keep an eye on how flu goes in the southern hemisphere’s winter and use that as a gauge for which strains may be most prominent during winter in the northern hemisphere, but there’s no real guarantee that the viral strains pinpointed as most likely for a given season will turn out to be an accurate prediction.

The global surveillance network consists of 130 centers in 101 countries monitoring which strains are most prevalent. These are the people who try to predict months ahead of time which patterns of infection will prevail in a given geographic area.

So, it’s possible to be vaccinated against the flu and still get the flu. Why? Because if you’re exposed to a circulating strain that’s not included in this year’s vaccination mix, then you’re not vaccinated against catching that particular form of the virus. The good news is, the predictions generally turn out to be pretty on target, preventing most people who receive a vaccine from developing influenza.

Keep in mind that even if the vaccine misses a circulating strain, if you choose not to be vaccinated, you can contract influenza more than once in a season if you’re exposed to two different circulating strains.

Final answer? Yes, you can receive a flu vaccine and still come down with the flu. But that doesn’t mean the vaccine didn’t work. It did work against the strain it targeted, and if it hadn’t, you might’ve had to go through that misery more than once. So, get the influenza vaccine as indicated. It will certainly prevent infection from the strains it targets, and at the least can save you half the misery of flu season.

Do you have a question for Emily? Send it to:

By Emily Willingham

Ask Emily

28 07 2011

What causes ear wax?

You do! Ear wax comes in two types. One is a thick, yellow wax, known as the “wet” type. The other is a greyish, flaky kind of wax, known as the “dry” type and most common among people of Asian origin and American Indians. Either way, its job is to clean, disinfect, and moisturize your ears, which makes it sound like a beauty product.

In reality, it is a health product that your body makes as a line of defense against things that might harm you, from bacteria to fungi to, yes, insects. For this reason, unless your ear wax is causing a health problem, medical folk recommend that you just leave it alone. It will cycle through and out of your ear, renewing as it goes.

Which type you have—wet or dry—depends on a single mutation in a single gene. Researchers have noted that Asians, especially people from East Asia, have ear wax that is dry and whitish. People whose ancestors are from Europe and Africa almost invariably have ear wax that is sticky and brown or yellow. If a person doesn’t dump cholesterol and other smooth fatty things into their ear wax, then the wax will consist primarily of dead skin flakes, the dry type.

Whether or not you make one or the other traces back to a single change in a single gene. This gene encodes a protein that makes ear wax . . . wet. With the single change in the genetic alphabet, a person doesn’t make wet wax. Researchers have even used this single change to trace the course of human migration throughout the world. Who knew ear wax could be so informative and useful?

I know that a fever is when my body’s temp goes up, but why does it go up? Why is THAT the reaction to whatever is going on in my body?

Let’s start by talking about bedbugs. One of the potential treatments for a bedbug infestation is to turn up the heat in the house to a level that bedbugs can’t survive. Turns out, the little bloodsuckers aren’t too fond of high temperatures. Many things that invade your body are like those bedbugs. They’re pretty comfortable at your normal temperature, but high heat can disable the molecules that keep them functioning. That’s why, when your body’s defense system recognizes an invader, one response may be fever.

Cells that detect these invaders can send out chemical signals with a great name: pyrogens. Pyro, of course, refers to fire or flame, and these chemicals travel to the brain’s thermostat center. There, they signal the brain to readjust the body’s temperature . . . kicking it up a few notches.

To a point, this higher temperature is thought to make things uncomfortable for microbes while not harming you too much. When a strong fever response takes things too far, fever can be harmful, but you might be surprised at exactly how high a fever needs to be to cause harm to you. According to the experts, a fever won’t cause brain damage unless it exceeds a very specific 107.6 F (42 C).

This general defense—it doesn’t target the specific invader; instead, it just relies on wholesale heating—is one of your body’s first responses to infectious invaders like bacteria or viruses. Meanwhile, your body is likely also getting to work on more specific tactics to deal with the unwanted intruders.

Do you have a question for Emily? Send it to:

By Emily Willingham

Image courtesy of CuriousGeoff