Differential Diagnosis of Common Cold

Differential Diagnosis: Common Cold

These can be symptoms of pneumonia, where the infection has gone deep into your lungs, or other serious conditions like tuberculosis or lung cancer.

Source: New Zealand Health1

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Back to: « Common Cold

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Pneumonia can be difficult to diagnose because it shares many symptoms with other conditions, such as the common cold, bronchitis and asthma.

Source: NHS Choices UK2

Differential Diagnosis for Common Cold

Flu: Cold, Flu, or Allergy?

Know the Difference for Best Treatment

Colds and flu are caused by different viruses. “As a rule of thumb, the symptoms associated with the flu are more severe,” says Hauguel. Both illnesses can lead to a runny, stuffy nose; congestion; cough; and sore throat. But the flu can also cause high fever that lasts for 3-4 days, along with a headache, fatigue, and general aches and pain. These symptoms are less common when you have a cold.

Source: NIH News in Health (NIH)3

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Airborne Allergies: “Allergies are a little different, because they aren’t caused by a virus,” Hauguel explains. “Instead, it’s your body’s immune system reacting to a trigger, or allergen, which is something you’re allergic to.” If you have allergies and breathe in things like pollen or pet dander, the immune cells in your nose and airways may overreact to these harmless substances. Your delicate respiratory tissues may then swell, and your nose may become stuffed up or runny.

Allergies can also cause itchy, watery eyes, which you don’t normally have with a cold or flu,” Hauguel adds.

Allergy symptoms usually last as long as you’re exposed to the allergen, which may be about 6 weeks during pollen seasons in the spring, summer, or fall. Colds and flu rarely last beyond 2 weeks.

Source: NIH News in Health (NIH)4

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Flu, Allergies: Cold, Flu, or Allergy?

Treatment depends on which you have. A health professional can help you choose the best therapy.

Common Cold

Seasonal Flu

Airborne Allergy

Source: NIH News in Health (NIH)5

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Asthma: Some preschool age children frequently wheeze when they get colds but don’t go on to develop chronic asthma. “But some kids start wheezing at age 3, and the problem continues,” says Lemanske. “These kids also tend to be more allergic.”

Source: NIH News in Health (NIH)6

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Strep Throat: Strep can be harder to detect in younger children, because it can cause a runny nose and other symptoms that make it seem like a cold.

Source: NIH News in Health (NIH)7

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Mycoplasma pneumoniae: Children younger than 5 years old often do not run a fever when they have M. pneumoniae infection. Instead they may have signs that appear more like a cold than pneumonia.

Source: CDC8

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Epstein-Barr virus: Many people become infected with EBV in childhood. EBV infections in children usually do not cause symptoms, or the symptoms are not distinguishable from other mild, brief childhood illnesses.

Source: CDC9

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Toxoplasmosis: Some people who have toxoplasmosis may feel as if they have the "flu" with swollen lymph glands or muscle aches and pains that last for a month or more.

Source: CDC Parasites10

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Trichinellosis: Many mild cases of trichinellosis are never specifically diagnosed because they are assumed to be the flu or other common illnesses.

Source: CDC Parasites11

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Pertussis: There are a lot of causes behind a person's cough and not every cough is pertussis. In general, pertussis starts off with cold-like symptoms and maybe a mild cough or fever. But after 1 to 2 weeks, severe coughing can begin. Unlike the common cold, pertussis can become a series of coughing fits that continues for weeks. The best way to know if you have pertussis is to see your doctor, who can make a diagnosis and prescribe antibiotics if needed.

Source: CDC12

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Bladder infection: A child who has a high fever and is sick for more than a day without a runny nose, earache, or other obvious cause should also be checked for a bladder infection. Quick treatment is important to prevent the infection from getting more dangerous.

Source: NIDDK (NIH)13

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Seasonal allergies: Is It a Cold or an Allergy?



Airborne Allergy

Source: MedLinePlus Magazine (NIH)14

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Flu: A cold is different from the flu (influenza). The flu usually develops more quickly. You’ll have fever and muscle aches within a few hours and will generally feel sicker than with a cold.

Source: New Zealand Health15

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Whooping cough: People with whooping cough are infectious from 6 days after exposure to the bacteria, when symptoms are like a normal cold

Source: New Zealand Health16

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Flu: Telling the difference between cold and flu

Cold and flu symptoms are similar but flu tends to be more severe.

Cold -- Flu

Appears gradually -- Appears quickly within a few hours

Affects mainly your nose and throat -- Affects more than just your nose and throat

Makes you feel unwell but you’re okay to carry on as normal - for example, go to work -- Makes you feel exhausted and too unwell to carry on as normal

Source: NHS Choices UK17

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Lyme disease: Not everyone with Lyme disease gets the rash. Some people also have flu-like symptoms in the early stages.

Source: NHS Choices UK18

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Lower respiratory tract infections: Lower respiratory tract infections

Common lower RTIs include:

  • flu - which can affect either the upper or lower respiratory tract
  • bronchitis - infection of the airways
  • pneumonia - infection of the lungs
  • bronchiolitis - an infection of the small airways that affects babies and children aged under two
  • tuberculosis - persistent bacterial infection of the lungs

Source: NHS Choices UK19

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  1. Source: New Zealand Health: health.govt.nz/ your-health/ conditions-and-treatments/ diseases-and-illnesses/ chest-infections-bronchitis
  2. Source: NHS Choices UK: nhs.uk/ conditions/ Pneumonia/ 
  3. Source: NIH News in Health (NIH): newsinhealth.nih.gov/ issue/ oct2014/ feature2
  4. ibid.
  5. ibid.
  6. Source: NIH News in Health (NIH): newsinhealth.nih.gov/ issue/ jun2014/ feature1
  7. Source: NIH News in Health (NIH): newsinhealth.nih.gov/ issue/ mar2013/ feature2
  8. Source: CDC: cdc.gov/ pneumonia/ atypical/ mycoplasma/ about/ signs-symptoms.html
  9. Source: CDC: cdc.gov/ epstein-barr/ about-ebv.html
  10. Source: CDC Parasites: cdc.gov/ parasites/ toxoplasmosis/ gen_info/ faqs.html
  11. Source: CDC Parasites: cdc.gov/ parasites/ trichinellosis/ disease.html
  12. Source: CDC: cdc.gov/ pertussis/ about/ faqs.html
  13. Source: NIDDK (NIH): niddk.nih.gov/ health-information/ urologic-diseases/ urinary-tract-infections-in-children/ all-content
  14. Source: MedLinePlus Magazine (NIH): medlineplus.gov/ magazine/ issues/ spring15/ articles/ spring15pg26-27.html
  15. Source: New Zealand Health: health.govt.nz/ your-health/ conditions-and-treatments/ diseases-and-illnesses/ colds
  16. Source: New Zealand Health: health.govt.nz/ your-health/ conditions-and-treatments/ diseases-and-illnesses/ whooping-cough
  17. Source: NHS Choices UK: nhs.uk/ conditions/ common-cold/ 
  18. Source: NHS Choices UK: nhs.uk/ conditions/ Lyme-disease/ 
  19. Source: NHS Choices UK: nhs.uk/ conditions/ Respiratory-tract-infection/ 

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Note: This site is for informational purposes only and is not medical advice. See your doctor or other qualified medical professional for all your medical needs.