Symptoms of Cold and Flu

People often confuse the common cold and the flu. It's understandable since the symptoms of the two are so similar. They are both primarily respiratory viruses that can leave you feeling pretty lousy, but there are some key differences. Influenza, or the flu, is a much more serious illness than the common cold. It claims thousands of lives each year, especially for those in high-risk groups, so it's important to know how it differs from the common cold.

Frequent Symptoms

The symptoms in common for cold and flu are congestion, cough, headache, and, in children, fever. But they differ in other symptoms and in the course of the illness. Although the symptoms of the common cold and the flu may look similar, the key difference is really how they make you feel. Most people feel bad when they have a cold but can typically still function. With the flu, it is hard to even get out of bed.

Symptoms of Cold

The common cold can cause different symptoms in different people. Many types of viruses cause colds so that may play a role in your symptoms. If your cold is caused by a rhinovirus but your friend's cold is caused by an adenovirus, you may not have the exact same symptoms, but they will still be pretty similar. Most people experience:

  • Runny or stuffy nose
  • Congestion
  • Cough
  • Headache
  • Sore Throat
  • Itchy or watery eyes
  • Fever (rare in adults but may occur in children)

Recognizing the symptoms of the common cold is important for a few reasons. If you realize what symptoms are bothering you the most, you will know which medications will help relieve them. You may also prevent unnecessary doctor visits if you know that you have a cold. Since your doctor cannot cure your cold, there is no reason to see him/her unless your symptoms last longer than two weeks.

If your symptoms do last longer than a week or two—or if you start to feel like you are recovering and then suddenly get worse—it's important to see your doctor and find out if you have developed another infection. Secondary infections like ear infections, bronchitis, and pneumonia are common complications of both colds and the flu. Since these illnesses may need different treatments, you should talk to your healthcare provider if you are concerned.

Symptoms of Flu

Recognizing symptoms of the flu is even more important than recognizing symptoms of a cold. Although they are similar, you should take note of a few key differences. The severity of your symptoms will usually give away the fact that you have the flu and not a cold. Colds often develop slowly—you start to feel a little worn out, then you may start sniffing, and then the full-blown congestion, sore throat, and coughing start.

The flu, on the other hand, hits you full force. You may feel fine when you go to bed and then wake up feeling absolutely terrible. Fever, body aches, and cough come on suddenly and painfully. Each year, between 3% and 11% of the US population gets symptomatic flu. The most common flu symptoms include:

  • Fever (not everyone with the flu will have a fever, but most do)
  • Chills
  • Body aches
  • Headache
  • Cough
  • Exhaustion
  • Mild congestion
  • Vomiting and diarrhea (uncommon in adults but occurs more frequently in children)

Quickly realizing that you may have the flu is vital. Seeking treatment from your doctor within the first 48 hours could make the difference in the length and severity of your flu. Also, it's important to know that the flu is not a stomach virus.

Rare Symptoms

Some symptoms are uncommon in colds as opposed to flu, and vice versa. In colds, it is less common to have fever in an adult, significant body aches, chills, or headache. In the flu, it is less common to have sneezing, stuffy nose, or sore throat.

If you see a rash, that is not a symptom of either cold or flu, and it is more likely that the condition is a different disease.

Children can experience ear pain with the flu. Mucus builds up in the sinuses, causing pressure and pain, and some children feel that pain in their ears. If the pain persists or becomes severe, your child may have developed an ear infection as a complication of the flu.

Many people refer to gastroenteritis as "the flu." But if your primary symptoms are vomiting and diarrhea, it is highly unlikely you actually have the flu. Influenza is the virus that causes the flu and it is a respiratory virus. There are several viruses and bacteria that can cause the "stomach flu," but none of them are influenza.

Severe symptoms of influenza are less common, and you should always seek medical help if you or your child experiences them.

In children:

  • Fast breathing, difficulty breathing, or ribs pulling in with each breath
  • Bluish lips or face
  • Chest pain
  • Severe muscle pain
  • Dehydration symptoms such as no urine for 8 hours, dry mouth, no tears when crying, fewer wet diapers than normal
  • When awake, the child isn't alert or won't interact
  • Seizures
  • Fever above 104 F, or any fever in an infant less than 12 weeks old
  • Fever or cough that improves but then returns or worsens
  • Worsening of chronic medical conditions

In adults:

  • Difficulty breathing
  • Chest pain or pressure
  • Abdominal pain or pressure
  • Dizziness
  • Confusion
  • Vomiting that's severe or won't stop
  • Flu-like symptoms get better but then come back with fever and worse cough

Complications/Sub-Group Indications

Certain people are at high risk for complications from the flu and should be started on treatment as soon as possible to prevent serious symptoms, complications, or hospitalization. Among those at highest risk are:

  • Pregnant women
  • Adults over age 65
  • Children under age 5
  • People with chronic medical conditions such as heart disease, asthma, or diabetes

If you aren't sure whether or not your health condition puts you at high risk for flu complications, talk to your healthcare provider before you get sick, so you will have a plan if you develop flu symptoms.

People with asthma are at higher risk of an asthma attack with either cold or flu. If you have other lung conditions such as chronic bronchitis or emphysema or chronic heart disease you are likely to have your symptoms worsened for weeks after you have otherwise recovered from a cold or flu. This can include a persistent cough. Sinus infections and ear infections can also follow cold or flu.

Pneumonia is one of the most serious complications of cold and flu. This can be due to the virus itself or bacterial infection of the weakened person's lungs. Pneumonia is often what leads to hospitalization and to many of the deaths attributed to influenza each year. Other serious and sometimes fatal complication of the flu inflammation of the heart, brain, or muscles, multi-system failure, and sepsis.

When to See a Doctor or Go to the Hospital

While colds and flu are the most common complaints seen by doctors, it often isn't necessary to get medical help for the common cold. Using a step-by-step symptom guide can help you evaluate each symptom to determine its possible cause, when you might need to see a doctor, and treatment options:

If you believe you might have the flu, try to see your health care provider within the first 48 hours of the onset of your symptoms. If you do need a flu test, it is more likely to be accurate if it is performed during this time frame. As well, antiviral medications are most effective when started in the first 48 hours.

You should always see a doctor if:

  • You are elderly and have a severe cold or flu symptoms.
  • A young child has a severe cold or flu symptoms.
  • You have a temperature of 100.4 F.
  • You have trouble breathing or chest pains.
  • You can't keep anything down.
  • You have a sore throat, and it hurts to swallow.
  • A cough is persistent and is either hacking or productive (producing phlegm or mucus) as this could be a sign of serious conditions including pneumonia to whooping cough.
  • If your symptoms worsen or persist for more than five days.

A Word From Verywell

Colds and the flu are some of the most common illnesses Americans deal with each year. They are often confused with one another but are actually very different infections. Knowing the differences between the two can help you decide how to treat your symptoms when they start and know whether or not you need to seek medical attention.

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