Summit Medical Group

In this image provided by Summit Medical Group, an unidentified man shows off his case of pityriasis rosea, which often appears in the shape of a Christmas tree.

It may start with a sore throat. After that, there's the aptly-named "herald" patch, a round or oval pink patch that usually shows up on the chest or abdomen, then fades. Days or weeks later, the pink dots start. Sometimes they're on the front, sometimes the back.

And what's really weird is their pattern.

"It was like a tattoo that covered my back in the shape of a Christmas tree," says Mark Jared Zufelt, a 41-year-old Seattle writer/director/photographer, who came down with the rash in his 20s. "It fanned out from the top and worked its way down. It was gross." Zufelt doesn't have a photo of his strange skin condition, but Summit Medical Group has a great example of what the condition, officially called pityriasis rosea, looks like.  

Despite its name, the Christmas tree rash has nothing to do with Christmas trees or even the holiday season. In fact, it usually shows up in the spring and fall, according to Dr. Kenneth Beer, a Palm Beach, Fla., dermatologist.

"Nobody really knows why people get it but a lot of the time, it follows a sore throat or upper respiratory tract infection," he says. Doctors believe the condition is caused by a virus, and it's not thought to be contagious. 

Itchy and scaly (each pink dot is covered with a thin white scale, like cigarette paper), the rash is fairly common and sometimes confused with ringworm, eczema or psoriasis. Beer says he sees about a dozen cases of Christmas tree rash a year, usually in people under the age of 40.

Ironically, his teenage son came down with the worst case he's ever seen.

Dermatlas at Johns Hopkins Medicine

This image provided by Dermatlas at Johns Hopkins Medicine, shows another view of pityriasis rosea.

"He was bright red and had it everywhere -- his chest, abdomen, back, arms, legs," says Beer. "He was miserable."

Treatment for the rash usually involves topical steroids and antibiotics.

"We'll put some people on oral medications but we usually just do topicals," he says. "But the other thing that helps is a little bit of sun or ultraviolet light, UVB. People can go outside and get 15-20 minutes of sun a day or go to their dermatologist's office and use their light boxes." Tanning beds, which primarily give off UVA rays, won't help, he says.

The rash, which Beer terms "uncomfortable but not horrible" usually goes away within two to four weeks with treatment. In addition to topical steroids, oatmeal baths can help alleviate the itching.

While pityriasis rosea has no connection to actual Christmas trees, holiday greenery isn't completely blameless when it comes to allergic reactions.

In 2007, a British teacher named Nicola Coleman made headlines when she broke out in red hives shortly after putting up a Norway spruce. Researchers have also found that some people are allergic to the mold found in pine or fir trees. They've dubbed this allergy -- which triggers a runny nose, sneezing and asthma attacks -- Christmas tree syndrome.

"You can also have contact dermatitis allergies to the sap in some of the trees," says Beer. "But that's totally different."

Zufelt says he doesn't remember what time of year it was when he broke out with his Christmas tree rash, but remembers that it definitely wasn't December.

"I know it wasn't Christmas because that would have been too serendipitous," he says. "It would have made the Christmas card had that been the case."

Related:

Do you hear what I hear? Your brain on Christmas music

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Getty Images stock

Can you actually eat yourself to death?

"I ate so much I'm about to burst!"

Someone at your Thanksgiving table will likely say some version of this tomorrow, after you've all stuffed your faces with turkey, mashed potatoes, sweet potatoes and the rest. But how much would you have to eat in order for your stomach to actually burst? Is that even possible?

"Interestingly enough, you can rupture your stomach if you eat too much," says Dr. Rachel Vreeman, co-author of "Don't Cross Your Eyes ... They'll Get Stuck That Way!" and assistant professor of pediatrics at Indiana University School of Medicine. "It is possible, but it's very, very rare."

A handful of reports over the years document the tales of people who literally ate themselves to death, or at least came dangerously close: Japanese doctors wrote in a 2003 case report that they believed it was a 49-year-old man's "excessive over-eating" that caused his stomach to rupture, killing him. And this 1991 case report describes a similar "spontaneous rupture" in an adult's stomach "after overindulgence in food and drink." 

Normally, your stomach can hold about one or one-and-a-half liters, Vreeman says -- this is the point you may reach if you overdo it tomorrow, when you feel full to the point of nausea. Pathologists' reports seem to suggest the stomach is able to do OK handling up to about three liters, but most cases of rupture seem to occur when a person has attempted to stuff their stomach with about five liters of food or fluid. (One of the reports Vreeman came across described the sad case of a woman whose stomach contained 12 liters of stuff.)

It takes a certain amount of misguided determination to manage to override your natural gag reflex and continue to eat (and eat and eat), which is why, not surprisingly, reports of ruptured stomachs caused by overeating are most common in people with some sort of disordered eating, or limited mental capacity, Vreeman says. 

"They have unusual eating habits to an extent that their bodies’ reflexes no longer respond as they normally do," Vreeman explains. "Their bodies’ reflexes have been ignored or abused for so long that they no longer vomit at the appropriate time. And then once the stomach gets to this extremely distended point, the stomach muscles are too stretched out to be strong enough to vomit the food out."

Speaking of strong stomachs, you'd best have one in order to read this next paragraph. If vomiting isn't happening, all that food and fluid still has to go somewhere. The increasing volume of stuff in the gut puts pressure on the stomach's walls, so much so that the tissue weakens and tears, sending the stomach contents into the body and causing infection and pain, Vreeman says. Surgical intervention is necessary to repair a ruptured stomach and save the patient's life. 

In particular, she says, anorexics or bulimics may be at risk. In fact, Cedars-Sinai, the non-profit hospital in Los Angeles, actually lists this as a "symptom" of bulimia: "In rare cases, a person may eat so much during a binge that the stomach bursts or the esophagus tears. This can be life-threatening."

Other reported cases of spontaneous stomach rupture happen in individuals with Prader-Willi syndrome, a congenital disease that is characterized by, among other things, a kind of disordered eating: an "intense craving for food," resulting in "uncontrollable weight gain and morbid obesity." according to the National Institutes of Health. In a 2007 study examining the deaths of 152 individuals with the condition, 3 percent of those deaths were the result of gastric rupture and necrosis. 

The takeaway here: This really happens, sometimes! Also: This is probably not going to happen to you. 

"Even if you're starting to feel a bit sick or tired and overwhelmed from eating so much at Thanksgiving, you're still far, far away from the scenario where you're going to make your stomach actually explode," Vreeman assures. 

Related:

• Are 'competitive eating' contests a terrible idea?
• The strange eating habits of Steve Jobs
• Can eating too much spicy food kill you?

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If Thanksgiving weekend is a time for gratitude, let's make the weekend before the holiday a time for whining. Actually, two studies out this week explore the upside of negative thinking. Sometimes, believing that everything's the worst can ultimately be for the best, the research suggests.

Fun fact 1: Complaining can help inspire people to change a bad situation. “In order to actually change the system, you’ve got to know what’s wrong with it,” says India Johnson, a graduate student at Ohio State University who helped lead a study set to appear in the journal Psychological Science.

Study participants read about a student at the Ohio university who wasn't happy with his experience with the school's freshman orientation. Some of the stories detailed the student's successful attempt to improve the orientation process; others read about the student's failure to do so. Then the volunteers were given an external review of the university from the Department of Education -- they could choose between reading a positive or negative report.

Interestingly, the students who'd read about the successful changes made to the freshman orientation were more likely to choose the negative report. Johnson explains, “In order for people to feel like they can actually affect the world and actually do something, they have to view the world as changeable. If you want people to be able to make that leap, you have to first get them to that point. Then they’ll be willing to seek out the negative information." 

Fun fact 2: The best two words to motivate an expert may be, "You stink!" Newbies thrive on positive feedback, but when you're dealing with a pro, it may be best to give it to him straight, according to a new study appearing in the Journal of Consumer Research.

In one study, researchers Stacey Finkelstein and Ayelet Fishbach, both of the University of Chicago, examined reactions of beginning and advanced French students. Those who were just starting the language were more likely to improve if their instructor gave them gentle feedback, but the old-timers thrived on harsh criticism. Like the Ohio State study, the research suggests that negative words can bring about positive change.

What's bugging you today? Get out your complaints in the comments so you'll be ready to give thanks on Thursday.

Related:

• Study explains why you'll miss your 'Community'
• A sweet tooth means a sweeter personality
• Upside to embarrassing moment: They make people like you

Want more weird health news? Find The Body Odd on Facebook.

Chris Hondros / Getty Images

Revelers clink beer glasses and enjoy themselves during an all day party at historic McSorley's Old Ale House March 17, 2004, in New York.

Sometime tomorrow, around the time your alarm clock rings, you will hate yourself for trying to keep up with your college self this St. Patrick's Day. You used to be able to bounce right back from hangovers; now, if you have more than two pints of Guinness tonight you know you'll feel it in the morning. What happened?

It's not your imagination. Our bodies really do start to lose the capability to process booze as we get older, an alcohol expert explains.

"The critical enzymes for breaking down booze are somewhat diminished in efficiency as we age," says Jim Schaefer, an alcohol metabolism expert and an anthropology professor at Union College in Schenectady, N.Y. The enzymes your body depends on to break down booze are alcohol dehydrogenase, or ALDH, and aldehyde dehydrogenase, or ADH. Excuse the alphabet soup, but ALDH breaks down ethanol (booze) into acetaldehyde, and then ADH breaks down the acetaldehyde into a non-toxic substance called acetic acid. "It has been suggested that acetaldehyde is one of the key toxic chemicals that influences the severity of a hangover," Schaefer says. "So any deterioration in ADH levels would contribute to worse hangovers."

Whiskey sales boom lifts Irish spirits

Another reason not to chase your college years tonight: Cheaper booze also tends to intensify hangovers. Inexpensive beer, wine and liquor are more likely to have higher congener content -- congeners are the "chemical soup" that results from the fermentation or distillation process, Schaefer explains. "The more expensive liquors are often filtered and triple or more distilled -- thus, cleaner alcohol, less junk," he says.

"As we age, we may be unable to avoid chemical changes that could be wrecking the efficiency of our liver, and we should avoid lousy intoxicants, as they are guaranteed to cause digestive or metabolic discomfort," Schaefer adds.

Let's review: If you are past your college drinkin' days, don't throw back a bunch of green-tinted Miller High Lifes. If you must imbibe tonight, stick to the fancy stuff, and your pounding headache Friday morning will be at least a little less pound-y.

Do you feel your hangovers have gotten worse as you've aged? At what age did you notice it? Or, do you generally avoid drinking enough booze to cause a hangover?

You can find The Body Odd on Twitter and Facebook, and follow Melissa Dahl @melissadahl.

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