Influenza
Body System: Respiratory System | Area Affected: Lungs, airways, nasal passages, and throat
Doctor to Consult: Pulmonologist or ENT Specialist
What It Is
Influenza: Influenza, commonly known as the flu, is an infectious disease caused by influenza viruses. Symptoms range from mild to severe and often include fever, runny nose, sore throat, muscle pain, headache, coughing, and fatigue. These symptoms begin one to four days after exposure to the virus and last for about two to eight days. Diarrhea and vomiting can occur, particularly in children. Influenza may progress to pneumonia from the virus or a subsequent bacterial infection. Other complications include acute respiratory distress syndrome, meningitis, encephalitis, and worsening of pre-existing health problems such as asthma and cardiovascular disease.
Why It Happens
Influenza arises due to factors affecting the Respiratory System. Respiratory conditions commonly result from infections, allergens, pollutants, or abnormal immune responses affecting the airways and lung tissue. While individual cases vary, a combination of genetic susceptibility, lifestyle factors, and environmental exposures typically contribute to the development of Influenza.
Who Gets It / Risk Factors
Who Is at Risk for Influenza
Individuals of all ages may be affected, with children and older adults facing higher vulnerability to respiratory illness.
A family history of respiratory system conditions may increase susceptibility to Influenza.
Contributing Factors
Smoking, air pollution exposure, occupational dust/chemical inhalation, and a history of childhood respiratory infections.
Co-existing health conditions such as asthma, allergies, or immune system disorders may compound the risk.
When to Seek Emergency Care
Severe difficulty breathing, blue discoloration of lips, or coughing up blood related to Influenza.
Sudden or rapidly worsening symptoms that impair basic daily function.
Difficulty breathing, severe pain, loss of consciousness, or high fever with confusion.
Medical Overview
A professional summary of diagnosis, treatment, and prevention.
Coughing, wheezing, or shortness of breath commonly experienced with Influenza.
Nasal congestion, throat irritation, or chest tightness associated with Influenza.
Changes in daily functioning or comfort levels that persist beyond a few days.
Scientific References
This content is based on established clinical guidelines and public health resources from the following authoritative sources.
Medically Reviewed for Accuracy
Medical Advisory Board
•Last reviewed: March 20, 2026Content is aligned with established clinical guidelines from authoritative medical institutions, including MedlinePlus (U.S. National Library of Medicine), the CDC, the NIH, and the NHS. All content is reviewed by our medical advisory board for accuracy and safety.