Viral gastroenteritis, widely known as “stomach flu,” is an inflammation of the stomach and intestines. It is caused by a viral infection in the digestive system. Despite its informal name, stomach flu is distinct from influenza, a respiratory illness affecting the nose, throat, and lungs. While influenza can cause some systemic symptoms, viral gastroenteritis primarily impacts the gastrointestinal tract.
Common Symptoms of Stomach Flu
Stomach flu symptoms often appear one to three days after exposure to the virus. Primary symptoms include nausea, vomiting, and watery diarrhea. Diarrhea is typically non-bloody, with loose, watery stools occurring multiple times a day. Abdominal cramps and pain are also common.
Other symptoms may include a low-grade fever, often around 100-101°F (37.8-38.3°C). Headaches, muscle aches, and fatigue are common. A temporary loss of appetite is also typical. Acute symptoms, including vomiting and diarrhea, typically resolve within one to three days. However, symptoms can sometimes persist for up to a week.
Distinguishing Stomach Flu from Other Illnesses
Differentiating stomach flu from other conditions with similar symptoms is important. Food poisoning, for instance, shares many gastrointestinal symptoms like nausea, vomiting, and diarrhea. A key distinction lies in the onset of symptoms; food poisoning typically manifests much more rapidly, usually within a few hours of consuming contaminated food, whereas stomach flu symptoms generally appear one to three days post-exposure. Food poisoning symptoms may also involve bloody diarrhea.
Influenza, or “the flu,” is often confused with stomach flu. However, influenza primarily affects the respiratory system, leading to symptoms such as cough, sore throat, severe body aches, and a high fever. While some overlap in general symptoms like fever and fatigue may occur, gastrointestinal symptoms are rare or mild in adults with influenza. Therefore, if digestive issues are the predominant concern, it is more likely to be stomach flu rather than respiratory influenza.
When to Seek Medical Attention
While most cases of stomach flu are self-limiting and resolve on their own, certain warning signs indicate the need for professional medical evaluation. The most significant concern is dehydration, which occurs when the body loses too many fluids and electrolytes from vomiting and diarrhea. Signs of dehydration in adults include excessive thirst, dry mouth and skin, infrequent urination or dark urine, dizziness, and lightheadedness. For infants and young children, signs can also include:
- A lack of tears when crying
- Sunken eyes
- A sunken soft spot on the head
- Being unusually sleepy
- Being irritable
Other concerning symptoms that warrant medical attention include a high fever, especially above 102°F (38.9°C) in children or 104°F (40°C) in adults. The presence of bloody or black, tarry stools, or blood in vomit, is also a serious indicator. Severe abdominal pain that persists, or an inability to keep liquids down for an extended period (e.g., 24 hours in adults, or more than 4-6 hours in infants), should prompt a medical visit. Additionally, if symptoms do not show improvement after several days, or if the affected individual is a very young infant, elderly, or has a weakened immune system, consulting a healthcare provider is advisable to prevent complications.