指甲上的白斑是怎么回事
[ 2007-05-14 13:38 ]
我們的指甲上有時會出現一些白色的小點，對于這些白斑，各個民族、各種文化都有不同的說法。不過從醫學上看，白斑確實也是一種病變哦。我們來看看詳細的解釋吧。
 Some cultures see the white spots as a good luck
sign, and even call them fortune or gift spots. There's also the old idea that
someone with a white spot on a fingernail is in love, or that the number of
white spots equals the number of "sweethearts" a girl has. In an Alice Hoffman
novel, a white spot appeared on a character's fingernail each time he lied, a
telltale sign like Pinocchio's growing nose.
But fibbing, falling in love, or winning the lottery actually have nothing to
do with white spots, unless you happen to hit one of your fingers in all the
excitement. Dermatologists (skin doctors) say that white spots and smeary
streaks happen to all of us, and are usually nothing to worry about.
The official name for white nail spots is the somewhat scary-sounding
punctate leukonychia. (In total leukonychia, the entire nail turns white.) Kids
and adults often have one or more random white dots or marks on their nails,
especially if they are hard on their hands. Dermatologists say the spots appear
because of repeated dings to the nail bed at the base of a fingernail (say, by a
striking ball when playing sports). Much rarer causes include infections,
systemic illnesses and dietary deficiencies.
White spots are a mix of keratin (a tough protein) and air. The spots are
places where, due to an minor injury to the nail bed, new nail cells were
incompletely formed or "keratinized." The white spots will rise higher as the
nail is pushed up by new growth from the nail bed. Since a nail grows about one
millimeter in 10 days, it can take months for the spotted part to reach the tip
for trimming off. Meanwhile, you can look at your nail spots and relive memories
of all the insults and injuries to your fingers in the past year.
（來源：how-come.net 英語點津 Annabel 編輯）
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