Common Cold and Flu Complications

The common cold and flu usually run their course and get better within a week, but sometimes complications of these illnesses can make you feel worse or can become serious. From dehydration to secondary infections (e.g., ear infections or pneumonia), it's important to pay attention to the symptoms that occur along with a cold or the flu—especially if they're lasting longer than seven to 10 days or are worsening.

Some people are at a higher risk of developing complications from common illnesses, which makes it's important to focus on prevention (like getting a flu shot) and getting proper care if you do get sick.

Woman afro american doctor general practitioner examining ear of a ill child. Ear infections.
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The flu and common cold may cause diarrhea and vomiting and can decrease your appetite. As a result, you can get dehydrated.

Symptoms of dehydration include:

  • Dry mouth
  • Dark-colored urine
  • Little or no urination
  • Fatigue
  • Headache

Do your best to prevent dehydration by consuming liquids such as water, herbal teas, soups, and smoothies. Try to sit up for at least half an hour after drinking or eating. You may need to sip slowly and space out your intake throughout the day if you're feeling nauseated. It's ok to take it slow.

Ear Infections

Ear infections, especially middle ear infections, can occur after a cold or the flu. Although adults do get them, they are more common in children.

Ear infections can be quite painful. Taking acetaminophen or ibuprofen will not cure them, but can relieve pain. Children younger than 6 months can be given acetaminophen, but not ibuprofen.

In some cases, these infections can be treated with antibiotics if they are bacterial.

Older children and adults are usually able to recognize an ear infection based on pain alone. For younger children, identifying an ear infection is a bit more difficult.

Be on the lookout for these signs:

  • Pulling on the ear
  • Tilting head from one side
  • Crying more than usual
  • Difficulty sleeping
  • Drainage from the ear
  • Problems with balance or hearing
  • Unexplained fever

Sinus Infections

Sinus infections occur when the sinus cavities get infected, and mucus often builds up as well. These infections can be uncomfortable or painful, and they affect people of all ages.

Symptoms of sinus infections include:

  • Pain or pressure in the face, especially around the eyes and nose
  • Congestion
  • Headache
  • Fever
  • Weakness and fatigue
  • Sore throat
  • Cough that may become worse at night
  • Bad breath
  • Loss of sense of smell

Symptoms of sinus infections are treatable with decongestants, pain relievers, saline sprays, and rinses. Sometimes antibiotics can treat the infection.


A nagging cough that lasts longer than two weeks may be a sign of bronchitis. This infection is usually caused by a virus, which means that it can't be treated with antibiotics.

Symptoms of bronchitis include:

  • A cough that may start dry and painful, and become productive with yellow or green mucus
  • Sore throat
  • Chest pain
  • Chest congestion
  • Shortness of breath
  • Wheezing
  • Chills
  • Body aches

If you notice any of the above, see your healthcare provider, who can evaluate you and recommend a treatment plan.


A painful, productive cough may indicate pneumonia. This condition is marked by a lung infection in which the lungs' air sacs fill up with pus or inflammation that interferes with oxygen flow.

Pneumonia is typically a secondary infection—one that occurs after you've had an infection such as a cold or the flu. It may be viral or a co-infection of a virus and bacteria.

Pneumonia is a very serious illness that should be treated early, so contact your healthcare provider immediately if you suspect any symptoms. 

Symptoms of pneumonia are:

  • Frequent, painful, and/or productive cough
  • Extreme fatigue
  • Chest pain
  • Fever
  • Chills
  • Headaches
  • Shortness of breath
  • Cyanosis (bluish or grayish coloring around the mouth )
  • Confusion or altered mental state

Rare Complications

The following complications are much less common, but they are serious. If the flu virus creeps into organs such as the brain or heart, it can cause widespread inflammation that may be life-threatening.

Serious complications include:

  • Myocarditis: Inflammation of the heart
  • Encephalitis: Inflammation of the brain
  • Multi-organ failure: Including respiratory and kidney failure
  • Sepsis: An infection in the bloodstream

People at Greatest Risk

According to the Centers for Disease Control and Prevention (CDC), those at the highest risk for complications resulting from the flu include people who have a weak immune system.

The following are high-risk populations:

  • People age 65 and older
  • Children under age 5, especially those under age 2
  • Pregnant people
  • Anyone with chronic medical conditions, such as asthma, diabetes, or heart disease
  • Those undergoing chemotherapy, who have had an organ transplant, who have HIV, or have another medical circumstance that affects the immune system

A Word From Verywell

If you have recently had a cold or the flu and your symptoms have changed, worsened, or have not improved after two weeks, you should see your healthcare provider. A visit to your healthcare provider will help you identify what is causing your symptoms and get you on the right treatment plan so you can avoid serious complications.

10 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  6. Smith SM, Fahey T, Smucny J, Becker LA. Antibiotics for acute bronchitis. Cochrane Database Syst Rev. 2014;(3):CD000245. doi:10.1002/14651858.cd000245.pub4

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By Kristina Duda, RN
Kristina Duda, BSN, RN, CPN, has been working in healthcare since 2002. She specializes in pediatrics and disease and infection prevention.