A cold is an infection of the upper respiratory tract. It's common and relatively harmless - but it sure doesn't feel that way when you have one. If it's not a runny nose, sore throat and a cough, it's watery eyes, sneezing and miserable congestion. Or maybe all of the above. In fact, because any one of more than 200 viruses can cause colds, symptoms tend to vary greatly.

Unfortunately, if you're like most adults, you're likely to have two to four colds a year. Children, especially preschoolers, may have between five and nine colds annually. Colds are particularly prevalent among children attending child care.

The good news is that your symptoms should improve within a week, although some colds may last as long as two weeks. If a cold lasts longer than that, see your doctor to make sure you don't have a secondary bacterial infection in your lungs, larynx, trachea, sinuses or ears.

• Sore throat

Signs and symptoms

The onset of cold symptoms occurs within one to three days after you're exposed to a cold virus. The first major symptom is usually a watery nose. You may also develop an itchy or sore throat, increased nasal congestion, slight body aches or a mild headache early in the course of the infection.

The discharge from your nose may become thicker and yellowish as your cold runs its course. Other signs and symptoms of a cold include:

• Sneezing

• Watery eyes

• Cough

• Low fever

• Mild fatigue

What makes a cold different from other viral infections is that you generally won't have a high fever. You're also unlikely to experience significant fatigue from a cold.

• fatigue

• fever

• Headache

• Sore throat

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