Influenza A usually starts suddenly with fever, body aches, cough, and feeling very tired, and can sometimes cause serious complications like pneumonia, especially in highā€‘risk people. If you or someone you know has trouble breathing, chest pain, confusion, or symptoms that rapidly worsen, emergency medical care is needed.

Key flu A symptoms

Most people with influenza A notice that they go from ā€œfineā€ to ā€œvery sickā€ over just a few hours.

  • Sudden fever (often 38Ā°C / 100.4Ā°F or higher).
  • Chills and shivering.
  • Dry cough that can be persistent.
  • Sore throat.
  • Runny or stuffy nose, sneezing.
  • Headache, often moderate to severe.
  • Marked fatigue and weakness, ā€œcanā€™t get out of bedā€ feeling.
  • Generalized body aches, muscle and joint pain.

Sometimes people, especially children, also have:

  • Loss of appetite.
  • Nausea, vomiting, or diarrhea.

How it differs from a cold

Influenza A feels more intense than a regular cold and tends to hit faster.

  • Onset: Flu symptoms appear suddenly over hours; colds usually build up slowly.
  • Severity: Flu brings higher fever, worse body aches, and more exhaustion than a cold.
  • Duration: Flu can keep you quite unwell for about 5ā€“7 days, with fatigue lingering longer.

Warning signs needing urgent care

While most recover at home, some symptoms mean things are getting dangerous and need sameā€‘day medical attention or emergency care.

  • Difficulty breathing, shortness of breath, or rapid breathing.
  • Chest pain, pressure, or a racing heartbeat.
  • Bluish lips or face, or very pale/gray skin in children.
  • Confusion, difficulty waking up, or seizures (especially in kids).
  • Persistent high fever for more than about a week, or symptoms improving then suddenly getting worse again.

When to call a doctor

Contact a healthcare professional promptly if:

  • You are pregnant, elderly, very young, or have chronic conditions (heart, lung, diabetes, immune problems) and develop fluā€‘like symptoms.
  • You are not keeping down fluids, are urinating much less, or feel dizzy on standing.
  • Symptoms are severe or you are unsure whether it is influenza, COVIDā€‘19, or something else.

Simple homeā€‘care tips

For otherwise healthy people with mild to moderate influenza A, home care focuses on rest and symptom relief.

  • Rest as much as possible; avoid strenuous activity.
  • Drink plenty of fluids (water, broths, oral rehydration solutions).
  • Use overā€‘theā€‘counter pain and fever relievers as directed by a professional.
  • Stay home and avoid close contact with others until at least 24 hours after fever goes away without medication.

If you describe your symptoms, it is possible to help think through whether they sound typical for influenza A and what kind of care might be appropriate (without replacing a professional medical assessment).