Cold & Flu Health Center
Is It a Stomach Flu or Influenza?
Do you know the difference between stomach flu and influenza? "Stomach flu" is a popular term but not the true medical diagnosis. The proper medical term for stomach flu is gastroenteritis.
Sometimes people mistake symptoms of stomach flu or gastroenteritis for the viral infection we commonly call "flu," which has symptoms of fever, congestion, muscle aches, and fatigue. Learn more about stomach flu and influenza so you can recognize flu symptoms and seek proper treatment.
How Does Stomach Flu Differ From Influenza?
Stomach flu actually refers to gastroenteritis or irritation and inflammation of the stomach and intestines (the gastrointestinal tract). Gastroenteritis may be caused by a virus, bacteria, parasites in spoiled food or unclean water, or another trigger such as lactose intolerance, which causes a reaction to dairy products.
Influenza (flu), on the other hand, is a viral infection that mimics a cold except that it starts forcefully with symptoms of fatigue, fever, and respiratory congestion. While more than 100 different virus types can cause a common cold, only influenza virus types A, B, and C cause flu. More severe cases of influenza can lead to life-threatening illnesses such as pneumonia.
In addition, while antibiotics can treat a bacterial infection, antibiotics cannot treat influenza because flu is caused by a virus.
What Are the Symptoms of Stomach Flu?
Symptoms of gastroenteritis or stomach flu include abdominal cramps, stomach pain, nausea, vomiting, and diarrhea. You may also have fever, headache, and swollen lymph glands, depending on the type of bug that causes it.
In severe cases of gastroenteritis, loss of bodily fluid can result in dehydration, a life-threatening condition that needs medical attention. Signs of dehydration include sunken eyes, light-headedness, increased thirst, dry or sticky mucous membranes in the mouth, lack of normal elasticity of the skin, decreased urine output, and decreased tears.
You can avoid dehydration by continuing to drink fluids. Bland foods -- like toast, rice, bananas, and applesauce -- may be good for starters. However, experts now recommend returning to a normal diet within 24 hours, if possible.
What Causes a Stomach Flu?
There are many causes of stomach flu, including bacteria such as E. coli, Campylobacter, Shigella, and Salmonella. Viruses can also cause stomach flu and are responsible for 30% to 40% of gastroenteritis cases in children. Common stomach flu viruses include norovirus or Norwalk-like virus, adenovirus, rotavirus, calicivirus, and astrovirus. Stomach viruses are notorious for spreading rapidly because of poor hand washing.
While not as common, parasites such as giardia and cryptosporidium can cause severe diarrhea and dehydration. Water-borne parasites are common in underdeveloped parts of the world that have unsanitary water supplies. It is recommended that travelers stick to bottled water to avoid water-borne parasites -- a potential cause of stomach flu.
Some foods may irritate your stomach and also cause gastroenteritis. Reaction to dairy products in someone with lactose intolerance is the most common example. Severe reactions to seafood is another example.
A lack of good hygiene can result in a stomach flu. For instance, improper hand washing after using the bathroom or after changing a baby's diaper can spread the infectious bug from person to person. Many doctors call stomach flu "a family affair" because it is so highly contagious and usually goes through all members of a family.
WebMD Medical Reference
Flu Guide
