If you see dark lines on the nail beds
Texas-sized moles aren't the only red flags for skin cancer--the disease can also develop under your nails. Yellowish, brown, or black stripes are a sign of cell damage, possibly from melanoma, the deadliest form of skin cancer, says Ariel Ostad, M.D., a dermatologist in New York City. With early detection and treatment, though, about 95 percent of cases are curable, so have your dermatologist take a second look.
If you see bright white stripes
Everyone gets white spots on their nails from time to time (usually it's a sign that you banged your finger in a drawer), but if you see long horizontal bands of discoloration on the nail's surface and you've been feeling fatigued lately, it could be bad news for your kidneys. "These bands can be a signal that the kidneys aren't able to filter out protein from your urine," Ostad says. That means your body is losing protein faster than you can shovel in filet mignon--and that can lead to kidney failure. Visit your doctor ASAP for a urine test.
If you see a patch of rough, dark skin
Unless you've been going overboard with the self-tanner, you could have diabetes, says Michael Smith, M.D., WebMD's chief medical editor. Excess insulin in your bloodstream can cause skin cells to multiply abnormally fast, leading to a buildup of tissue and melanin. This makes the skin look darker and feel thicker. "It most commonly occurs in the armpits, neck, or groin," Smith says. A simple blood test can determine whether you have the disease, which affects about 24 million Americans--nearly a quarter of whom are undiagnosed.
Your Eyelids, Knees, And Elbows
If you see small, soft lumps that look white or waxy
The good news: It's not a zit. The bad news: These are small deposits of cholesterol, Smith says. Unfortunately, "by the time they appear, your cholesterol levels are probably sky high; this is a serious risk factor for heart disease." Yet reducing your numbers by just 10 percent slashes that risk by as much as a third. See your doctor for a cholesterol check, and ask her about lifestyle changes or prescription drugs that can get your levels down.
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If you see thinning hair
Could you fashion one of Britney's weaves out of the hair clogging your drain? Excessive hair loss is a common indicator of a thyroid disorder, which affects about 10 percent of American women. When your thyroid (a gland in the middle of your neck) is out of whack, it can disrupt the balance of male and female sex hormones. The result: More strands in your brush and hair that feels coarse and brittle, says Sandra Fryhofer, M.D., a physician in private practice in Atlanta. Your doc can measure the amount of thyroid-stimulating hormone in your blood--if you have too much or too little, you'll need medication to regulate it.
If you see your scalp shedding like a snake
If skin flakes have suddenly made your shoulders look like the Alps in February, it could be due to your to-do list. "An intense load of stress causes your body to produce excess amounts of the hormone cortisol," Ostad says. "In addition to wreaking havoc on your immune system (making you more vulnerable to colds) and your metabolism (making you pack on pounds), cortisol can also dry out your scalp." A drugstore dandruff shampoo will deflake your locks, but unless you want a permanent case of shoulder snow, try to get more sleep, breathe more deeply, and loosen up your overpacked schedule.
If you see thick, dark hair (or stubble) in a diamond shape
Is that forest sprouting on your abs thick enough to hide a family of hobbits? Dense, coarse hair that extends up toward your belly button (rather than growing downward from the top of the pubic bone) could be a sign of polycystic ovarian syndrome (PCOS), says Pamela Berens, M.D., an ob-gyn at the University of Texas Medical School. Caused by overproduction of androgens, the condition can lead to irregular or heavy periods, weight gain, acne, and thick, dark hair on the belly, face, chest, and back. As many as one in 10 women have PCOS, which can be a risk factor for serious problems like infertility and heart disease. If you have symptoms, see your ob-gyn; she might prescribe birth control pills to get your hormones back in check.
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If you see a white, yellow, or orange coating
If your licker looks as if someone painted it with bright-colored gunk, you could be spilling your gut in your sleep, Fryhofer says. Normally, a one-way valve at the bottom of the esophagus makes sure that whatever goes down doesn't come back up. Acid reflux occurs when this valve opens spontaneously and the contents of your stomach make a break for your throat, leaving your tongue coated in digestive acids and you with a serious case of Godzilla breath. Most reflux can be treated with OTC antacids or simply by avoiding acidic and spicy foods; if those measures don't work, see your doctor. You may need prescription meds to reduce your body's production of stomach acid.
If you see undereye circles that won't go away
Unless you've taken a second job at the midnight trucking radio network, a sudden onset of dark rings could be chalked up to allergies. The chain reaction, according to Ostad, goes like this: An allergen hits your body, which in response releases histamine; this chemical makes blood vessels swell with blood and other fluids, and voila: Dark patches show up where the skin is thinnest. A skin test can determine which allergen is causing your symptoms.
If you see a yellowish bump on your eyeball
No, you haven't developed a rare case of optic acne. Instead, a slightly raised nodule on the white of your eye is a symptom of a harmless condition called pinguecula. "It's nothing more than an overgrowth of collagen triggered by damage from sun, wind, or dust," says Traci Goldstein, an optometrist at Metropolitan Vision Correction Associates in New York City. Keep your eyes moist with lubricating drops and don shades anytime you're outdoors (make sure your specs offer 100 percent protection against UVA and UVB rays) to prevent the bump from growing larger.
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