Harvard Health Letter

The respiratory tract and its infections

This is the time of year when respiratory tract infections act up, so we've created a brief guided tour to the common cold and four of its fellow misery makers. Please refer to the illustration as you read along. Flu is not included because the focus is on anatomical locations in the respiratory tract, and flu's effects are widespread. A couple of themes emerged as we put this article together. First, it's true: washing your hands may be your best defense against respiratory infection. Second, antibiotics are important arrows in the treatment quiver, but they've been overused, especially for sinusitis and bronchitis.

1. Common cold

What is it? Inflammation of the mucous membranes that line the nose.

Symptoms. The medical term, viral rhinitis, may not be so familiar, but the symptoms are a stuffed-up and runny nose and sneezing. About half the time a cold causes a sore or scratchy throat, and that's often the first symptom, although by the second or third day, the nasal problems predominate. If a cough develops, it may not start until several days after the rest of the symptoms get going and may linger for several weeks after they are gone. Adults rarely have fever with colds — the absence of fever is one way to tell it's a cold — but children sometimes do.

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