What should you know about abdominal influenza?

Gastroenteritis irritates the stomach and intestines, causing symptoms such as nausea, vomiting, diarrhoea, and abdominal cramps. Influenza is a respiratory viral infection more often associated with fever, cough, headache, chills, fatigue, and body aches. Some people with influenza can also develop digestive symptoms, but those symptoms alone do not establish the cause.

People sometimes say “abdominal flu” or “stomach flu” when a short-lived digestive infection passes through a household. Several viruses and other infections can cause gastroenteritis, and contaminated food can produce similar symptoms. True influenza mainly affects the airways and can sometimes lead to pneumonia. A clinician may distinguish these illnesses by the symptom pattern, recent exposures, examination findings, and testing when needed.

Take frequent small sips of water or an oral rehydration drink, especially after vomiting or diarrhoea. When fluids stay down, try small portions of bland food and return gradually to normal meals. Rest, wash hands carefully with soap and water, avoid preparing food for other people while unwell, and do not share towels or utensils. Before using anti-diarrhoeal medicine, check with a pharmacist or clinician if there is blood in the stool, a high fever, pregnancy, a long-term condition, or medicine use that may affect treatment choices.

Seek urgent medical assessment for severe or worsening abdominal pain, blood in vomit or stool, confusion, fainting, breathing difficulty, a stiff neck, or signs of marked dehydration such as very little urine, unusual drowsiness, or inability to keep fluids down. Babies, older adults, pregnant people, and anyone with a weakened immune system can become unwell more quickly, so contact a clinician early if symptoms are persistent or worsening. Respiratory symptoms with chest pain or shortness of breath also need prompt assessment.

Ask whether the pattern fits gastroenteritis, food poisoning, influenza, or another condition; whether dehydration is developing; and whether any current medicines should be paused or adjusted during vomiting or diarrhoea. Also mention recent travel, sick contacts, unusual meals, pregnancy, long-term health conditions, and any blood, fever, breathing symptoms, or reduced urination.