Most Common Flu Symptoms: What To Look For - Forbes

The flu is a respiratory illness caused by the Influenza virus that infects the upper respiratory system and sometimes the lungs, says Hannah Newman, M.P.H., director of infection prevention at Lenox Hill Hospital in New York. While most cases of the flu are mild, severe cases can lead to serious illness and, in very rare cases, death.

The flu's duration can vary from person to person depending on their age and location, personal health history and the virulence of the strains in a given flu season, says J. Wes Ulm, M.D., Ph.D., a clinician, medical researcher and bioinformatic scientific resource analyst at the National Institutes of Health in Maryland.

The general rule of thumb is that symptom onset tends to kick in within one to three days following exposure, and the illness itself lasts for roughly a week, says Dr. Ulm. "Most symptoms resolve by five to seven days, though patients frequently complain of a lingering cough, fatigue and weakness persisting for another week or two," he says, adding that individuals with immune deficiencies and young children whose immune systems are still developing can be contagious for up to a week.

The flu can be contracted year-round, but high activity is usually seen during flu season, says Newman. In the U.S., flu season usually starts in October and peaks between December and February, with some seasons extending through May.

While anyone can get the flu, at-risk groups include older adults over the age of 65, immunocompromised individuals and children under the age of 2, although those in the 2- to 5-year-old age range are at an elevated risk, explains Dr. Ulm. "Pregnant women, people with diabetes and individuals with a range of underlying health issues—heart disease, obesity, asthma, metabolic (genetic) disorders, kidney and liver conditions—are also more vulnerable to severe bouts with the flu," he says.

Symptoms of the Flu

According to Newman and the CDC, common flu symptoms include:

• Fever
• Chills
• Cough
• Sore throat
• Runny nose or congestion
• Muscle or body aches
• Headaches
• Fatigue
• Nausea
• Vomiting
• Diarrhea

Not everyone who catches the flu experiences all of these symptoms. Instead, it's common to have one symptom or a combination of several symptoms, says Newman. For example, not everyone with flu will experience fever, and gastrointestinal symptoms are more common in children, she says.

According to Dr. Ulm, individuals diagnosed with the flu should seek medical attention in the event of:

• Prolonged and marked shortness of breath or other respiratory distress (particularly if accompanied by chest pains)
• Seizures or persistent dizziness
• Severe and persistent weakness to the point of impeding even basic daily activities
• Marked exacerbation of an underlying condition

Parents caring for children with the flu should also be on the lookout for signs of dehydration (especially poor feeding and fewer wet diapers than normal in an infant) and indications of poor oxygenation like cyanosis (in which the skin, nail beds, lips and area around the mouth take on a bluish or gray discoloration), explains Dr. Ulm.

Differences Between the Flu, Common Cold and COVID-19

Although the flu, common cold and COVID-19 are all contagious respiratory illnesses, they are caused by different viruses, explains Newman. "The flu is caused by the Influenza virus, COVID-19 is caused by SARS-CoV-2, and the common cold can be caused by a number of circulating viruses like rhinoviruses, seasonal coronaviruses and parainfluenza," she says.

Symptoms of these three viruses are often similar, so taking a test is necessary to differentiate between them, says Newman. Getting a diagnosis from your doctor is also recommended.

Common cold symptoms are usually milder than the flu or COVID-19 and don't start as intensely/abruptly, says Newman. Common colds are also less likely to lead to serious complications like pneumonia, sepsis, hospitalization or death, she says.

The flu often presents with cold-like symptoms, but also tends to manifest more often with fevers, severe headaches and muscle aches, a more pronounced cough and much more marked and long-lasting fatigue and weakness, explains Dr. Ulm.

When it comes to COVID-19, it shares flu symptoms like fever, muscle aches, pronounced fatigue, weakness and diarrhea (especially in kids), says Dr. Ulm. Runny noses are also becoming more common with newer COVID-19 variants, particularly subvariants of the Omicron strain.

"COVID-19 often presents with lasting anosmia or dysgeusia—loss of smell or altered taste," says Dr. Ulm, symptoms that are rare with the common cold or flu.

Adblock test (Why?)