Flu vs. the Common Cold: Symptoms and Treatment

Learn which illness you have, how to feel better, when to see the doctor, and more.

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Patients may find it difficult to distinguish between a cold and the flu, and pharmacists can help them determine if self-treatment is appropriate.

Having a cold or the flu is a familiar event for many of us. A cold usually comes on slowly, starting with a runny or stuffy nose, sneezing, and a sore throat. The flu often comes on quickly with extreme tiredness, fever, body aches, and a cough. Both usually last for one to two weeks. The symptoms are similar and difficult to tell apart. The flu is typically worse than a cold and more likely to cause complications that require prescription medications or hospitalization.

How Do I Know If It's a Cold or the Flu?

The flu and the common cold are respiratory illnesses caused by different viruses. There are hundreds of cold viruses that can cause a cold any time of year. There are fewer flu viruses. The main two types are influenza A and B.

Although the flu is most common during flu season, which lasts from October to mid-May, it can happen any time of year. Unfortunately, the flu and a cold cannot be reliably told apart by either the symptoms or the time of year.

[See How to Get Your Sick College Kid Home Quick.]

When Should I See a Doctor?

Complications of the flu and a cold include strep throat, pneumonia, bronchitis, sinus infections, and ear infections. Signs of these complications include a persistent fever (greater than 101 degrees Fahrenheit for more than three or four days in adults), painful swallowing, persistent coughing (lasting longer than three weeks), persistent congestion, and headaches (lasting longer than one week). People with chronic health problems, such as obesity, asthma, diabetes, and heart disease, can have additional complications.

People with a high risk of developing complications should see their doctor if they have flu-like symptoms. Although there is no cure for the flu, a doctor can prescribe oseltamivir (Tamiflu) or zanamivir (Relenza). These antiviral drugs can lessen the severity and shorten the duration of the flu, thus reducing the likelihood of complications. These drugs are most effective if taken within 48 hours of the start of flu symptoms.

If complications are already present, the doctor can prescribe additional medications, such as antibiotics, or recommend hospitalization. The U.S. Centers for Disease Control and Prevention (CDC) lists the following groups as at high risk for developing complications:

• Children younger than 5 years, but especially children younger than 2 years

• Adults 65 years and older

• Pregnant women

• American Indians and Alaskan natives

• People who have chronic medical conditions

If your doctor prescribes medications to treat the flu, it is important to take the medicine promptly and properly. Take time to talk to your pharmacist about how to take the medications and what to expect. When treating the flu, either after seeing a doctor or on your own, the symptoms should begin to clear up within one week. If they do not, contact your doctor.

The CDC lists emergency warning signs to watch for that require immediate medical attention, especially for those in the high-risk groups.

[See Flu Season: What to Know to Stay Healthy.]

Emergency Warning Signs

In Children:

• Fast breathing or trouble breathing

• Bluish skin color

• Not drinking enough fluids

• Not waking up or not interacting

• Being so irritable that they do not want to be held

• Flu-like symptoms that improve but then return with fever and worse cough

• Fever with a rash

In addition to the signs above, get medical help right away for an infant who has any of these signs:

• Unable to eat

• Trouble breathing

• No tears when crying

• Significantly fewer wet diapers than normal

• Younger than 2 months with fever of 100.4 degrees Fahrenheit or higher

• 3 to 6 months old with fever of 103 degrees Fahrenheit or higher

• Older than 6 months with fever of 104 degrees Fahrenheit or higher

In Adults:

• Difficulty breathing or shortness of breath

• Pain or pressure in the chest or abdomen