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What are the causes of an upper respiratory infection?

An upper respiratory infection, or the common cold, is an infection that affects nasal and throat passages. Treatment is usually simple, unless a person also has an asthma-like chronic respiratory condition.

A virus enters the body for incidence of an upper respiratory infection (URI), usually through the mouth or the nose. It can be transmitted through touch, or through sneezing and coughing.

Any place where people gather in an enclosed space, such as a classroom, office or home, may be a high-risk area for URIs to spread.

A URI typically lasts between 3 and 14 days, anywhere. URIs can develop into more serious conditions in some cases, such as infections with the sinus or pneumonia.

In this article , we look at how to identify a URI, its possible causes and the treatments available.

What is a URI?

A URI affects the nasal passages and throat.
A URI affects the nasal passages and throat.

A URI is an infection that affects the passages of the upper air including:

  • the larynx, which is the muscular organ containing the vocal cords
  • the nasal cavity, which is the space above and behind the nose
  • the nasal passages, or the nostrils
  • the pharynx, which is the cavity behind the nose and mouth

Adults get from two to three URIs a year. Children , especially young children, may experience more because they are still developing their immune systems.

Fall and winter are the most frequent times of the year for experiencing a URI.


The most common symptoms of a URI include:

  • coughing
  • discomfort in the nasal passages
  • mild fever, which is more common in children
  • excess mucus
  • nasal congestion
  • pain or pressure behind the face
  • a runny nose
  • a scratchy or sore throat
  • sneezing

Less common symptoms can include:

  • bad breath
  • body aches
  • headache
  • hyposmia, or the loss of sense of smell
  • itchy eyes


The causes of URIs are viral nearly always. If a person sneezes or coughs, droplets of tainted saliva and mucus stream out to the air. Others may breathe in, or land on surfaces that others touch.

If another person then puts his hand near their mouth, they may become infected.

There are over 200 common cold viruses which cause URIs.

Other risk factors include:

  • damage to the airways or nasal cavity
  • not washing the hands frequently
  • contact with groups of children
  • crowded places, such as airplanes and buses
  • having an autoimmune disorder
  • removal of adenoids or tonsils, which are part of the immune system
  • smoking and secondhand smoke
  • spending time in the hospital or in a care center


Drinking plenty of fluids and resting may help reduce the severity of symptoms.
Drinking plenty of fluids and resting may help reduce the severity of symptoms.

In general, people at home will self-diagnose a URI.

If a person has any concerns about getting a URI or a more serious disease, they should speak to a doctor.

URIs are self-limiting, meaning they usually resolve without medical treatment at all.

However, URIs can sometimes lead to other illnesses, or initial symptoms may be similar to other conditions, including:

  • allergic reactions or seasonal allergies
  • asthma
  • bronchitis
  • sinusitis
  • influenza (the flu)
  • pneumonia

If the symptoms do not resolve, or get worse over time rather than better, it is best to talk to a doctor.

URI treatment generally involves limiting dysfunction. The following things may help to decrease symptom severity or duration:

  • applying petroleum jelly to sore areas, which may include the lips and nostrils
  • avoiding smoky or fume-filled areas
  • avoiding steep temperature changes
  • drinking plenty of fluids
  • increasing indoor humidity
  • resting as much as possible
  • using soft tissues when blowing the nose

Some over-the-counter medications will benefit adults with symptoms of URI, too. Such as:


  • brompheniramine (Bromfed)
  • chlorpheniramine (Chlor-Trimeton)
  • diphenhydramine (Benadryl)


  • acetaminophen (Tylenol)
  • ibuprofen (Advil)


  • oxymetazoline (Afrin)
  • phenylephrine (Sudafed PE)
  • pseudoephedrine (Sudafed)

Home remedies

Some people use home remedies to aid in relieving symptoms of URI. Home remedies encompass:

  • echinacea
  • garlic, especially when raw
  • honey, especially in hot ginger or lemon tea
  • lemon juice and lemon tea
  • root ginger in hot water

When to see a doctor

A person should see a doctor if their symptoms last longer than 2 weeks.
A person should see a doctor if their symptoms last longer than 2 weeks.

Although most URIs resolve without medical attention, they can increasingly get worse. It should be best to see a doctor if:

  • breathing becomes difficult
  • a fever lasts more than 3 days
  • the URI impacts an existing condition
  • the symptoms lasts more than 2 weeks
  • the lips turn blue
  • swallowing becomes difficult
  • symptoms become worse over time
  • the URI recurs soon after going away


There is no way to avoid having to get a URI. These infections are particularly common in wintertime and are almost inevitable if a person spends time indoors with other people.

Nonetheless, there are steps a person may take to reduce the risk. These are particularly useful during the fall and winter months. Preventive measures include:

  • avoiding cigarette smoke
  • avoiding crowded and enclosed spaces
  • avoiding sharing drinking glasses and utensils
  • cleaning and disinfecting areas that other people touch, such as shared keyboards
  • covering the mouth and nose when sneezing and coughing
  • eating a healthful diet
  • washing the hands frequently
  • exercising regularly


In most cases, an untreated URI clears up. Although the symptoms can be uncomfortable, there are several easy measures to help.

The majority of people recover within 2 weeks from a URI. When the symptoms get worse or become serious, however, it is best to speak to a doctor for a proper diagnosis.