Respiratory Tract Infection

Respiratory tract infections are among the most common illnesses affecting millions of people each year, ranging from mild colds to serious lung infections that require medical attention.

Table of contents

• What is a Respiratory Tract Infection?
• Parts of the Body Affected
• Types of Respiratory Tract Infections
• Common Symptoms
• Causes and How They Spread
• Who is at Higher Risk?
• How Doctors Diagnose These Infections
• Treatment Options
• How to Care for Yourself at Home
• When to See a Doctor
• How to Prevent Respiratory Tract Infections
• Possible Complications

What is a Respiratory Tract Infection?

A respiratory tract infection (RTI) is an infectious disease that affects the parts of your body involved in breathing^[1]. These infections can occur in your nose, sinuses, throat, airways, or lungs^[1]. Most respiratory tract infections get better without treatment within one to two weeks, though sometimes you may need to see a doctor^[1].

Respiratory tract infections are extremely common. In England and Wales, about a quarter of the population visits their doctor because of a respiratory infection each year^[4]. These infections are responsible for 60% of all antibiotic prescribing in general practice^[4].

Parts of the Body Affected

• Nose
• Sinuses
• Throat (pharynx)
• Voice box (larynx)
• Trachea (windpipe)
• Bronchial tubes
• Bronchioles
• Lungs

Types of Respiratory Tract Infections

Respiratory tract infections are usually divided into two main groups based on which part of the breathing system they affect^[1].

Upper respiratory tract infections affect the sinuses and throat. The upper respiratory tract is considered the airway above the vocal cords^[3]. These infections include^[1]:

• Common cold
• Sinusitis (sinus infection)
• Tonsillitis
• Laryngitis
• Acute rhinitis
• Acute otitis media

Lower respiratory tract infections affect the airways and lungs. The lower respiratory tract consists of the trachea, bronchial tubes, bronchioles, and lungs^[3]. Lower respiratory infections are generally more severe than upper respiratory infections and are the leading cause of death among all infectious diseases^[3]. They include^[1]:

• Bronchitis
• Bronchiolitis
• Chest infection
• Pneumonia (lung infection)
• Tracheitis

Some infections, such as flu, COVID-19, and respiratory syncytial virus (RSV), can affect both the upper and lower respiratory tracts^[1][2].

Common Symptoms

Symptoms of respiratory tract infections can vary depending on the cause and which part of your body is affected^[2]. Common symptoms include^[1]:

• A cough – you may bring up mucus (phlegm)
• Sneezing
• A stuffy or runny nose
• A sore throat
• Headaches
• Muscle aches
• Breathlessness, tight chest, or wheezing
• A high temperature (fever)
• Feeling generally unwell

Additional symptoms may include hoarse voice or loss of voice, fatigue, facial pain, and swollen lymph nodes^[2]. Lower respiratory infections often present more severe symptoms like persistent cough, sputum production, fever, or breathlessness^[17].

Causes and How They Spread

Viruses cause most respiratory tract infections^[2][11]. However, bacteria and even fungi can also cause these infections^[2]. Since most infections are caused by viruses, antibiotics will not help them get better^[1].

Common viral causes include^[2]:

• Common cold viruses
• Influenza A and B virus (the flu)
• SARS-CoV-2 virus (COVID-19)
• Respiratory syncytial virus (RSV)
• Varicella-zoster virus
• Herpes simplex virus

Bacterial causes can include^[2]:

• Streptococcus bacteria, like group A strep and Streptococcus pneumoniae
• Haemophilus influenzae bacteria
• Moraxella catarrhalis bacteria

Respiratory tract infections are often spread through the coughs and sneezes of someone with an infection^[1]. The viruses and bacteria that cause these infections are contagious and can spread from person to person through^[2]:

• Respiratory droplets when someone coughs, sneezes, or talks
• Sharing eating or drinking utensils (like forks, spoons, cups, or water bottles)
• Contact with objects or surfaces with germs on them (such as doorknobs, light switches, phones, or toys)

Who is at Higher Risk?

Respiratory illnesses can make anyone sick^[6]. However, certain people have risk factors that can increase their chances of getting very sick from these infections.

You might be at higher risk for complications if you^[1][2][6]:

• Are over 65 years old
• Are a child younger than 2 years old
• Are pregnant
• Have a weakened immune system – for example, because you have a condition like diabetes or you’re having chemotherapy
• Have a long-term health condition, such as a heart, lung, or kidney condition
• Smoke
• Have pulmonary fibrosis or another interstitial lung disease
• Are HIV-positive

People with these risk factors may have the hardest time recovering from the illness^[5].

How Doctors Diagnose These Infections

Healthcare providers usually diagnose respiratory infections based on your symptoms and may perform a nasal swab or throat culture^[2]. If your symptoms are mild and your tests are negative for infections like flu or strep throat, you might have one of hundreds of common cold viruses, which providers don’t often test for^[2].

A detailed history and physical exam will be performed by your healthcare provider^[15]. Certain testing may also be done, such as^[3]:

• Pulmonary function testing to evaluate airways and lung function
• Rapid viral testing in some cases
• Breath tests that can diagnose lung infections
• Mucus samples to determine what’s causing your infection

In 2013, researchers developed a breath tester that can promptly diagnose lung infections^[3]. A systematic review of clinical trials found that the relative risk reduction of chest x-ray utilization in children screened with rapid viral testing is 77% compared with controls^[3].

Treatment Options

Treatment for a respiratory tract infection will depend on the cause of your infection^[1]. Many lower respiratory infections are self-limited and resolve without the need for additional treatment^[14].

If your infection is caused by a virus (like the common cold), it will usually clear up by itself after a few weeks. Antibiotics will not help^[1]. Antibiotics are only used to treat bacterial infections and are not used for treating viral infections because they do not work for this type of infection^[1].

If your infection is caused by bacteria (like pneumonia), a doctor may prescribe antibiotics^[1][8]. Make sure you complete the whole course as advised by your doctor, even if you start to feel better^[1].

Other treatments that may be recommended include^[8][15]:

• Cough suppressants
• Expectorants to loosen congestion
• Inhaled corticosteroids
• Pain relievers
• Supplemental oxygen
• Techniques to clear mucus, such as nasal washes or airway clearance devices

In cases of serious infections, treatment in a hospital may be necessary. Hospital treatments may include intravenous fluids, humidified oxygen, or ventilation support if severe respiratory problems develop^[14].

How to Care for Yourself at Home

Most respiratory tract infections pass within 1 to 2 weeks. You can usually treat your symptoms at home^[1]. Here’s what you should do^[1][20]:

Do:

• Get plenty of rest
• Drink lots of water to loosen any mucus and make it easier to cough up
• Drink a hot lemon and honey drink to help soothe a cough (not suitable for babies under 1 year old)
• Gargle with warm salty water if you have a sore throat (children should not try this)
• Raise your head up while sleeping using extra pillows to make breathing easier and clear your chest of mucus
• Use painkillers to bring down a fever and help ease a sore throat, headaches, and muscle pain
• Use a vaporizer or humidifier to add moisture to your bedroom

Don’t:

• Let children breathe in steam from a bowl of hot water as there’s a risk of scalding
• Give aspirin to children under 16
• Smoke – it can make your symptoms worse

How to make a hot lemon and honey drink: Squeeze half a lemon into a mug of boiled water. Add 1 to 2 teaspoons of honey. Drink while still warm. Do not give hot drinks to small children^[1].

How to gargle with salt water: Dissolve half a teaspoon of salt in a glass of warm water. Gargle with the solution then spit it out – do not swallow it. Repeat as often as you like^[1].

A pharmacist can suggest treatments to help relieve your symptoms, such as decongestants and nasal sprays^[1]. You can also buy cough medicines and throat lozenges, although there’s little evidence to show they help^[1]. Some treatments contain paracetamol and ibuprofen. If you’re taking these medicines separately, be careful not to take more than the recommended dose^[1].

When to See a Doctor

You should see a doctor if you have symptoms of a respiratory tract infection and^[1]:

• You feel very unwell or your symptoms get worse
• You’ve had a high temperature for more than 3 days
• You cough up blood or bloodstained mucus
• You’ve had a cough for more than 3 weeks
• You’re pregnant
• You’re over 65
• You have a weakened immune system – for example, because you have a condition like diabetes or you’re having chemotherapy
• You have a long-term health condition, such as a heart, lung, or kidney condition

You may have pneumonia if your symptoms are severe^[1]. Call emergency services if you have severe trouble breathing^[20].

How to Prevent Respiratory Tract Infections

There are actions you can take to help protect yourself and others from health risks caused by respiratory illnesses^[6][16].

Core prevention strategies:

• Stay up-to-date with immunizations, which are available for flu, COVID-19, and RSV (for eligible groups). Talk to your doctor about what may be recommended for you and your family^[6]
• Practice good hygiene, like washing your hands regularly for at least 20 seconds and cleaning commonly touched surfaces^[6][17]
• Take steps for cleaner air – bringing in fresh outside air, purifying indoor air, or gathering outdoors – as possible in places where people live and work^[6]
• Boost your immune system by maintaining a balanced diet rich in fruits, vegetables, lean proteins, and whole grains. Get regular exercise, prioritize sufficient sleep, and manage stress effectively^[17]

To avoid spreading an infection:

If you’re sick with a respiratory infection^[1][19]:

• Stay home and away from others (including people you live with) until your symptoms are getting better and you have not had a fever for at least 24 hours
• Cover your mouth when you cough or sneeze
• Wash your hands regularly
• Throw away used tissues immediately
• When you return to normal activities, take added precautions over the next 5 days, such as wearing a well-fitted mask, physical distancing, or practicing good hygiene

If you keep getting respiratory tract infections or you’re at high risk of getting one, you should^[1]:

• Ask your doctor about the annual flu vaccine
• Ask if you should have the pneumococcal vaccine – this helps prevent pneumonia
• Stop smoking if you smoke
• Avoid close contact with sick individuals

Possible Complications

Upper respiratory infections like colds rarely lead to complications^[2]. However, respiratory infections can sometimes cause inflammation in your lungs, leading to pneumonia^[2].

If bacterial or fungal infections are left untreated, they can travel to other parts of your body and cause^[2]:

• Meningitis
• Rheumatic fever
• Scarlet fever
• Sepsis
• Organ damage

You might be at higher risk for complications from an infection if you have certain health conditions or a compromised immune system, or if you’re older than 65. Newborns are also at higher risk for severe illness^[2].

Last year in the United States, it was estimated that at least 1 million people were hospitalized and more than 70,000 people died from respiratory virus illnesses^[6].