Colds

There isn't a single illness that can be identified as a cold. A cold may cause sneezing, nasal congestion, headaches, sore throats and other symptoms, but there are over 200 different viruses that can cause these symptoms.  Nearly everyone has had a cold as it is such a common ailment, in fact, that doctors refer to it as the "common cold." In 1998 alone, more than 65 million people in America reported having colds and nearly half (29.8 million) were children under the age of 17. Since many people don't go to the doctor when they have colds, the actual number is probably much higher. A cold usually goes away in about a week, but the symptoms, which can include sneezing, nasal congestion, headaches, slight fever, sore throat and others, are unpleasant enough to make a person feel uncomfortable. Over-the-counter cold medicines can help relieve these symptoms. If cold symptoms last for more than two weeks, it is a good idea to check with a doctor to determine whether another illness, such as a sinus infection, is present. A Closer Look at Colds
		This is a picture of a cold virus. Though there are over 200 of them, they all pretty much look the same. After you catch one of the viruses, your body builds up immunity to it, and you are less likely to catch that cold again. That's is one reason why adults generally have fewer colds than children do.  Adults are immune to more of the cold viruses.
		Cold and flu viruses enter the nose, mouth and eyes through droplets in the air and through contact with the things we touch. Cold symptoms appear 18 to 48 hours after exposure to a virus. Flu attacks stronger and faster than colds, and usually strikes between December and March. Though colds and flu share many of the same symptoms, colds are less severe, do not last as long, and do not include the high fever of flu.
		Blood vessels in and around the nose dilate (or get bigger) in response to the virus. This speeds up the arrival of germ-fighting cells and causes the mucous membrane to swell. The body also releases extra histamine, a chemical that causes blood vessels to dilate even more.
		Your body's fight against the virus results in irritation, swelling and increased mucus production. The mucus flushes the viruses down the throat. Both the virus and the germ-fighting cells in the mucus can irritate the throat, causing the soreness and coughing you might experience with a cold.
		The swelling in the nose can block air passages and sinus openings, which causes congestion and could lead to bacterial infections of the sinuses.
		The same process can happen in the ear. Swelling around the opening in the eustachian tube (which connects the middle ear with the throat) traps bacteria and fluid in the middle ear. This can result in an infection and the earaches that many people suffer.
		The body's virus-fighting efforts put a strain on your whole body. That's what triggers the aches, pains, fatigue and fever that often accompany a cold.
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