Influenza viruses types A, B and C cause the illness known as the flu. Influenza viruses types A and B are primarily responsible for seasonal flu outbreaks, which typically begin in October or November and run through March. The Centers for Disease Control and Prevention, or CDC, reports approximately 5 to 20 percent of the U.S. population contracts the flu each year. Flu infection symptoms vary in severity from person to person. Those with pre-existing medical conditions often become the most ill with the flu.
High Fever
High fever is a characteristic symptom of the flu. The Mayo Clinic notes adults typically run a temperature of 101 F (38.3 C) or higher. Children commonly run a fever of 103 F to 105 F (39.4 C to 40.6 C). Over-the-counter fever reducers such as acetaminophen or ibuprofen can relieve fever.
Headache and Body Aches
The CDC states headache commonly accompanies the flu. Headache usually coincides with the onset of fever. Body aches in the muscles and joints are also common with the flu.
Fatigue
Fatigue is another characteristic symptom of the flu. The sense of weariness can be profound with the flu, notes the CDC. This symptom distinguishes flu from the common cold, which typically causes mild fatigue at worst.
Dry Cough
The CDC advises flu often causes a dry cough, meaning the cough produces no phlegm. While other symptoms of the flu typically ebb in three to seven days, the cough associated with flu may not completely resolve for two weeks or more. Importantly, a dry cough that suddenly produces phlegm may indicate the development of pneumonia.
Stuffy or Runny Nose
A stuffy or runny nose can be a symptom of the flu, notes the Mayo Clinic. Typically, a runny nose caused by the flu is not as severe as that caused by a cold.
Sore or Scratchy Throat
The CDC notes that flu may cause a sore or scratchy throat. Coughing often aggravates this symptom. The sore throat associated with the flu typically begins to improve within three to seven days of the onset of the illness.
Nausea and Vomiting
Children are more likely than adults to experience nausea and vomiting with the flu, advises the CDC. In a child with a high fever and vomiting, dehydration is a possible complication. Be watchful for signs of dehydration such as dry mouth, decreased tear production and low urine output. If you have concerns, call your doctor.
References
- Centers for Disease Control and Prevention: Seasonal Influenza, The Disease
- Centers for Disease Control and Prevention: Clinical Signs and Symptoms of Influenza
- Centers for Disease Control and Prevention: Influenza Symptoms and Laboratory Diagnostic Procedures
- Centers for Disease Control and Prevention: Influenza Symptoms
- University of South Carolina School of Medicine, Microbiology and Immunology Online: Influenza Virus
