Dematologists Pop Some Myths Surrounding Zits : Health: There’s no proof that certain foods promote acne, doctors say. Washing the skin doesn’t really help, and can in fact aggravate the condition.

Like a monster from a horror movie, it’s back to haunt you. Red, unashamed and smack on the end of your nose. It’s the attack of the killer pimple!

If only you hadn’t eaten that chocolate bar yesterday! If only you had stayed away from the fried chicken! Maybe if you just pick at it a little. . . . Whoa! Hold it right there.

How much of what you believe about acne--what causes it and how to get rid of it--is true? And how much is merely rumor that you picked up during seventh-grade slumber parties? While millions of teen-agers have acne some time or another, pimples are not a hot topic of conversation in most social circles. So, a lot of theories--some true, some not so true--are surreptitiously spread. Here are a few of the more common beliefs:

1. Chocolate, fried or greasy foods, caffeine and dairy products cause acne.

Wrong. Sorry, but it’s not that easy. This food myth has long been passed down as the reason for any pimple outbreak following a major holiday, but studies have proven it false. Dr. Ira Bell, a dermatologist in El Toro, said, “If you took a thousand people and you fed them chocolate, potato chips and fried foods, and you took a thousand people and fed them healthy foods, there would basically be no difference.”

Dermatologist Dr. Daniel Dwyer of Costa Mesa agreed: “Foods don’t really correlate (with acne). There may be an individual who reacts a certain way to a food, but no correlation can be proven with a large study.”

The one substance in food that might aggravate acne is iodine, used in commercial table salt. But Dr. Alex Miller, a dermatologist in Yorba Linda, discounted this theory: “There is an acne-like rash that can be produced from massly over-consumed iodine, but there really has to be massive amounts, not like the amount that is contained in salt.”

So, a doctor is not going to argue with the occasional patient who comes in and complains that whenever he drinks a cola or eats potato chips, he breaks out. But, for most people, advising against these foods is needless. Most likely, Miller said, those individual reactions are triggered by the person’s guilt and anxiety about eating junk food.

More than anything, Dwyer said, acne is brought on by hormonal fluctuations and a family history of acne.

2. Stress causes people to break out.

True. Why? No one knows for sure, but some doctors suspect it is linked to the rise in hormone levels. In any case, at least everyone else looks bad during final exam week too.

Bell commented: “It also doesn’t help to know that stress causes acne because you can’t tell people, ‘Don’t stress,’ and the best treatment for acne is not tranquilizers.”

3. People with large pores have more acne.

This one can be true, sometimes. Acne forms when oil secreted at the base of the hair follicle rises to the surface and tries to escape through the pores. Bacteria love to prey on this oil, causing an infection at the pore. People who produce more oil tend to have larger pores, and since acne thrives on oil, the people with larger pores tend to have more acne too.

As Bell pointed out, though, “It’s not like if you have large pores and shrink them down, your acne will get better, because there’s no way to do that.”

4. Touching the face spreads oil and dirt and worsens acne.

This is not as true as some might believe. Casual touching of the face does not worsen acne, but pressure does.

Said Miller: “If people are constantly resting their chin on their hand, and they do that every day for a long period of time, they sometimes end up plugging up pores and heating them up.” This combination of heat and pressure produces the acne that is common under a football player’s chin guard and shoulder pads and on a weight-lifter’s back.

5. Makeup makes acne worse by trapping oil on the surface.

Probably false. People used to believe that any sort of makeup at all would trigger a flare-up. Then, doctors said that only oil-based makeups are a problem. Now, doctors are not so sure about that, either.

A few people already susceptible to acne will react to oil-based makeup by producing more pimples, Miller contended. Because no one can predict how oil-based makeups will affect a certain individual’s complexion, dermatologists usually recommend that patients avoid heavy moisturizers and stick to water-based foundations.

6. Drinking water will clear up a complexion.

“Absolutely not,” Miller said. While drinking water does not hurt anything, it probably doesn’t have much effect on oil production in the skin.

Bell agreed: “A lot of people talk about cleansing the skin with eight glasses of water a day. I don’t think there’s any good evidence that that does anything but exercise your kidneys.”

Besides, Miller reminded, “We have a water shortage.”

7. Wash three or four times a day to rid the skin of dead cells.

This is really unnecessary, and over-washing can even make acne worse. Washing once or twice a day is plenty.

“Over-washing or scrubbing aggravates acne,” Bell warned, “because it breaks the pimples under the skin and causes them to go on to a red pimple, or a pus pocket, or a cyst, whereas otherwise they wouldn’t have.”

8. Squeezing a pimple really does help because it allows the oil to escape.

Wrong again. Doctors have been warning acne-sufferers for years not to pick, squeeze or pop pimples.

“The way most people do it,” Bell explained, “is to take their fingernail and dig the top of it off and cause it to be an open, red, weeping sore.

“You can take a person with very, very mild acne, say 10 whiteheads scattered across their face, and make them look horrible by having them pick at it.”

Miller explained one common problem he sees in patients who try to clear up their acne by hand: “The pimples that suffer the most from picking are the red pimples with no pus heads. People look at that and say, ‘Oh there must be pus inside of that. I’m going to give it a good squish.’ Then when nothing comes out they get really upset. They pick the top of it off trying to get to where the action is.

“So then all they’ve done is caused a scab to form, a crust on top of a pimple that’s been squished. And they’ve pushed some of that garbage out of the pore and into the surrounding skin.”

9. Going out in the sun helps clear up the skin.

True, for many acne sufferers. “In studies that have been done, 80% of the people will improve after going in the sun,” Miller said. “The way the sun helps is simply by damaging the skin and causing it to repair itself.”

Other physicians have different theories about why a case of acne might improve in the summer. Dwyer said, “Maybe it’s the beneficial effect of the (ultraviolet) rays on acne, or maybe it’s because they’re away from the stresses of school.”

While a day at the beach may be a popular prescription for acne, ultraviolet light harms the skin in other ways and can cause cancer.

10. Acne ends between ages 18 and 20.

Sorry, but that’s not true. Just because acne usually starts at puberty doesn’t mean it ends after driver’s ed, prom, graduation or even marriage. (Contrary to another much-repeated myth, having sex does not clear up acne.)

Doctors disagree about the age that acne usually goes away. While Bell said that most males have clear skin by their late teens, Miller said the average age that a man’s skin clears up is 25.