Each year, between 25 to 50 million cases of influenza, or the flu, are reported within the United States, according to estimates provided by FluFacts.com, a website established by Genentech, a founding member of the biotechnology industry. Cough, fever and headache are common flu symptoms in patients infected by the influenza virus. Patients who develop severe or persistent flu symptoms should seek additional care from a medical professional.
Cough
Patients with the flu often develop dry cough symptoms as a result of this infection. Symptoms of cough can develop when the flu virus inflames or irritates the delicate lining of the lungs. Affected patients can experience recurrent cough episodes that may contribute to sensations of pain or discomfort within the chest or throat. Patients who develop a congested cough or spit up mucus during cough episodes should seek additional care from a doctor as these symptoms can be signs of an alternate infection, such as pneumonia.
Fever
The immune system naturally increases the body's temperature when infectious pathogens attack the body. As a result, approximately 80 percent of patients infected with the flu virus develop a fever as a symptom, reports Genentech. Patients with the flu typically have a fever that exceeds 100 degrees Fahrenheit, which resolves within 3 to 4 days of onset. Fever symptoms may be accompanied by sweating, chills or body aches in certain patients with the flu. If fever symptoms persist or become worse, affected patients should consult a physician for further care.
Headache
Headache symptoms can arise in patients approximately 1 to 4 days after initial exposure to the flu virus, reports KidsHealth, a children's health information website supported by the Nemours Foundation. Painful headache symptoms can be uncomfortable and may persist until the infection resolves. Patients with headache symptoms can have difficulty concentrating while at work or school or may be unusually sensitive to loud or abrupt noises. Use of an over-the-counter pain medication, such as acetaminophen, can help alleviate headache symptoms of the flu in affected patients.
