Cold, Flu & RTIs: An Overview

Everything you need to know about cold, flu and respiratory tract infections (RTIs), including causes, telltale signs and treatment.

What is the difference between colds and flu?

Both common colds and flu are caused by viruses, and both are respiratory infections. As a result, it can be difficult to tell the two apart – at least at a first glance. Though some symptoms are present in both conditions, for instance a blocked or runny nose, sore throat and headaches, flu symptoms are generally more severe. The following symptoms can be present in flu, but generally aren't present in a cold:

  • Running a fever (temperature of 38ºC or higher)
  • Severe muscle aches
  • Severe fatigue
  • Nausea and vomiting
  • Diarrhoea and/or stomach pains

The other difference between the two is longevity. While colds might only last for a few days, up to a week or so in the majority of cases, flu symptoms can be present for up to two weeks.

How do symptoms differ between colds, flu and RTIs?

Cold symptoms include the following:

  • Blocked or runny nose
  • Sore throat
  • Headaches
  • Muscle aches
  • Coughing
  • Sneezing
  • Elevated temperature
  • Feelings of pressure in the ears and face
  • Loss of taste and/or smell

Flu symptoms, however, include the following:

  • Running a fever (temperature of 38ºC or higher)
  • Sore throat
  • Headaches
  • Severe muscle aches
  • Dry coughing
  • Severe fatigue
  • Difficulty sleeping
  • Loss of appetite
  • Nausea and vomiting
  • Diarrhoea and/or stomach pains

Respiratory tract infection (RTI) symptoms, on the other hand, include:

  • Running a fever (temperature of 38ºC or higher)
  • Blocked or runny nose
  • Sore throat
  • Headaches
  • Muscle aches
  • Throaty cough bringing up mucus/phlegm
  • Breathlessness or a tight chest

When should I see a doctor with a cold, flu or RTI?

We generally only recommend seeing a doctor for cold, flu and RTI symptoms in the following cases:

  • You are under the age of 5
  • You are over the age of 64
  • You are pregnant
  • You have a pre-existing long-term health condition
  • You have a weakened or compromised immune system
  • Your symptoms have not improved after 7 days

That said, although the majority of colds, flu and RTIs clear within a few days, if the above don't apply to you and you are at all concerned about your symptoms, don't hesitate to book an appointment with one of our GPs.

What forms of RTI are there?

Some of the most common types of respiratory tract infection found in the UK today.

Flu

Almost as common as it is contagious, flu is a virus that many of us will have experienced at some point in our lives.

Chest infections

An infection causing inflammation of the lungs and lower air passages.

Sinusitis

Inflammation in the sinus lining, often confused with cold or flu since it generally follows those conditions.

Tonsillitis

Where tonsils become swollen and infected. Common in children, but also experienced by adults.

Viral infections

Cold and flu are two of the most common viral infections worldwide, affecting people of all ages.

Respiratory Tract Infections (RTIs)

Affect airways and the lungs, causing breathlessness, coughing and a tight chest.

Cold

Experienced by people once a year on average. Usually not serious, but still frustrating, with no cure as of writing.

Sore throat

Where the throat feels scratchy or sore, making it difficult to speak or swallow. Results from viruses or bacteria.

Cough

A reflex that clears the throat, airways and lungs to prevent serious infections. Can be painful, if not persistent.

Bronchitis

Infection of the lower airways, causing mucus production, coughing and occasionally, wheezy breathing.

Glandular fever

AKA 'mono', a common condition affecting the neck glands. Experienced by teenagers and adults in their 20s.

Nasal congestion

Better known as a blocked nose, and occurring with a medical issues like colds, flu and hay fever.

Can I treat my cold, flu or RTI with antibiotics?

No. As colds and flu and the majority of RTIs are caused by viral infections, antibiotics will have no effect. In these cases, antibiotics will not relieve your symptoms or speed up your recovery from any of the above conditions.

Even if antibiotics were effective, we would be hesitant to prescribe them – though doing so is entirely at an individual doctor's discretion. We have complete faith in the doctors on our platform to make the right decision for each patient.

With all of this in mind, it is important to note that there is a small percentage of RTIs that are caused by bacterial infections, for which your doctor may prescribe antibiotics if they deem it appropriate to do so.

It is thanks to the continued rise of antibiotic resistance that we are increasingly hesitant to prescribe antibiotics. As Dr Tom Micklewright, one of our medical officers, wrote in February 2019: "Antibiotic resistance...occurs when bacteria change and become non-responsive to first-line antibiotic solutions". That means that with continued use of antibiotics to treat ailments that can, in the majority of cases, be safely managed at home, we could see the development of advanced cold, flu and RTI strains that don't respond to any available medication – so it is no wonder we avoid using antibiotics unless they are absolutely necessary, as any other medical organisation should.

Your cold, flu and RTI questions, answered

Illustration of a consultation between patient and doctor

Viruses that cause colds, flu and RTIs are generally spread days before symptoms start to appear in an infected individual. There are steps you can take to stand you in good stead in avoiding catching any of the above, however:

  • Keeping your hands clean with warm water and soap
  • Avoiding sharing towels, cups, cutlery and so on with people already displaying symptoms
  • Avoiding touching your eyes or nose if you think you have come into contact with the virus
  • Staying fit and healthy
  • Stopping smoking
  • Tempering your alcohol consumption
  • In the case of flu, having the flu vaccination

It is no secret how easily colds, flu and RTIs can be spread, but there are measures you can implement to reduce the risk:

  • Keeping your hands clean with warm water and soap
  • Using tissues to catch germs when you cough, sneeze or blow your nose
  • Disposing of used tissues as soon as possible

There is evidence to suggest that regular physical activity can improve your chances of avoiding the development of cold and flu entirely. Our in-house exercise physiologist Ben Fletcher has written a comprehensive blog on exactly this subject, but the major takeaway points are as follows:

  • Studies have shown that exercise helps to strengthen the immune system, equipping the body to more effectively fight off infections like colds, flu and RTIs
  • It is safe to exercise when you have a cold, the flu or an RTI – but be sensible, don't try to break any records or personal bests
  • Be wary of exercising when taking medicine that increases your heart rate as a side effect or risk experiencing shortness of breath, or trouble breathing altogether
  • It is less safe to exercise when you are feverish, as exercising in these circumstances puts more stress on the body than is really necessary
Illustration of a consultation between patient and doctor

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