Q: Why is stomach flu more common in the winter?

A: Norovirus and the related rotavirus are two of the most common causes of the "stomach flu," also called gastroenteritis. According to the Centers for Disease Control and Prevention, norovirus spreads quickly in closed places. The highest number of cases happens between November and April — when we tend to spend more time indoors.

Gastroenteritis is characterized by a multitude of symptoms including fevers, chills, abdominal pain, nausea, vomiting, and diarrhea. Once a person is exposed to a virus, symptoms will appear within one and three days, and continue for up to a week, in some cases.

The illness is usually self-limited — meaning that patients simply have to wait it out.  But acute viral gastroenteritis can lead to dehydration as a result of vomiting and diarrhea. So the most important aspect of treatment is to stay hydrated, either through water or  sports drinks (to help replenish electrolytes and nutrients). But be mindful of the sugar content; high-sugar fluids can make dehydration worse in some people, such as those with diabetes or those taking certain medications. Occasionally, intravenous fluids may be needed to help replace fluid losses.

There are no specific medications to combat the virus; antibiotics kill bacteria, not viruses.  Loperamide, a medication used for reducing frequency of diarrhea, can be helpful in treating that aspect of the infection. But it should be used only for a day or two; after that, contact your physician.

More serious symptoms include persistent high fever, blood or pus in the stool, an inability to keep down fluids, or changes in personality; these are not typical of a simple case of viral gastroenteritis, so contact your physician immediately.

Erik Polan, D.O., practices internal medicine at the Philadelphia College of Osteopathic Medicine.