ConditionLungs & breathing
Respiratory Infections
Respiratory infections are infections of the airways and lungs. Upper respiratory infections affect the nose, sinuses and throat, such as colds, sinusitis and sore throats. Lower respiratory infections affect the windpipe, bronchi and lungs, such as bronchitis, bronchiolitis and pneumonia. Most are caused by viruses, get better within 1 to 3 weeks and do not need antibiotics. Difficulty breathing, high fever, chest pain, or symptoms that improve and then worsen need medical care.
Also called: Respiratory tract infections, RTI, upper respiratory infection (URI), lower respiratory infection (LRTI), chest infection
At a glance
- Upper
- Common cold, sinusitis, pharyngitis, tonsillitis, laryngitis, ear infections.
- Lower
- Bronchitis, bronchiolitis, pneumonia, whooping cough, flu and COVID-19 affecting the lungs.
- Causes
- Mostly viruses (rhinovirus, influenza, RSV, coronaviruses); some bacteria (strep, pneumococcus, mycoplasma, pertussis).
- Typical duration
- Colds 7 to 10 days; acute bronchitis cough up to 3 weeks.
- Treatment
- Rest, fluids, symptom relief; antivirals for flu or COVID-19 in some people; antibiotics only for bacterial infections.
When to get help
Call 911 or go to the ER
- Severe difficulty breathing, gasping, or unable to speak in full sentences
- Blue or gray lips or face
- Chest pain, confusion, extreme drowsiness or fainting
- A baby or child with fast breathing, ribs pulling in with each breath, grunting, or pauses in breathing
See a doctor within a day or two
- Fever of 39 °C (102.2 °F) or higher lasting more than 3 days, or any fever in a baby under 3 months
- Shortness of breath, wheezing or coughing up blood
- Symptoms that improve, then come back worse
- Respiratory symptoms in someone over 65, pregnant, or with lung disease, heart disease, diabetes or weak immunity
Book a routine appointment
- A cough lasting more than 3 weeks
- Frequent or recurring chest infections
- Sinus symptoms lasting more than 10 days
Usually safe to manage at home
- Runny nose, sneezing, sore throat and mild cough without breathing difficulty
- A cough after a cold that is gradually improving
Upper vs lower respiratory infections
| Upper respiratory infections | Lower respiratory infections | |
|---|---|---|
| Location | Nose, sinuses, throat, larynx | Trachea, bronchi, bronchioles, lungs |
| Examples | Common cold, sinusitis, pharyngitis, tonsillitis, laryngitis | Acute bronchitis, bronchiolitis, pneumonia, whooping cough |
| Main symptoms | Runny or blocked nose, sneezing, sore throat, hoarseness | Cough, phlegm, wheeze, chest tightness, shortness of breath |
| Severity | Usually mild | Ranges from mild to life-threatening |
Common causes
Viruses
- rhinoviruses (most colds)
- influenza (flu)
- SARS-CoV-2 (COVID-19)
- respiratory syncytial virus (RSV), a major cause of bronchiolitis in babies
- adenoviruses, parainfluenza viruses (croup), human metapneumovirus
Bacteria
- Streptococcus pyogenes (strep throat)
- Streptococcus pneumoniae (pneumonia, sinusitis, ear infections)
- Mycoplasma pneumoniae ("walking pneumonia")
- Bordetella pertussis (whooping cough)
- Haemophilus influenzae
Symptoms
- runny or stuffy nose, sneezing
- sore throat, hoarse voice
- cough, dry or with phlegm
- fever, chills, body aches
- headache and fatigue
- wheezing, chest tightness or shortness of breath in lower infections
Viral vs bacterial: does it need antibiotics?
Most respiratory infections are viral and antibiotics do not help. Green or yellow mucus does not mean bacterial infection. Antibiotics are considered for:
- strep throat confirmed by testing
- bacterial pneumonia
- sinusitis lasting more than 10 days, severe, or worsening after initial improvement
- whooping cough
Antivirals such as oseltamivir for flu and nirmatrelvir-ritonavir for COVID-19 work best when started early, especially in higher-risk people.
Who is at higher risk
- babies and young children
- adults over 65
- pregnant people
- people with asthma, COPD, heart disease, diabetes, kidney disease or weakened immunity
- smokers
Diagnosis
Most infections are diagnosed from symptoms and examination. Tests include rapid strep, flu, COVID-19 and RSV tests, pulse oximetry, chest X-ray for suspected pneumonia, and blood tests when severely ill.
Treatment and home care
- Rest and plenty of fluids.
- Pain and fever relief: acetaminophen (paracetamol) or ibuprofen at the label dose. No aspirin for children or teenagers.
- Saline nasal spray and steam for congestion.
- Honey for cough in people over 1 year. Never give honey to babies under 12 months.
- Decongestants short term for adults; avoid if you have high blood pressure.
- Cough and cold medicines are not recommended for children under 6.
- Stay home while you have a fever.
Prevention
- annual flu vaccine, COVID-19 vaccines as recommended
- RSV vaccines or preventive antibodies for older adults, pregnancy and infants as recommended
- pneumococcal and whooping cough (Tdap) vaccines
- handwashing and covering coughs and sneezes
- not smoking and avoiding secondhand smoke
- improving indoor ventilation
Frequently asked questions
What is the difference between upper and lower respiratory infections?
Upper respiratory infections affect the nose, sinuses and throat, causing runny nose, sneezing and sore throat. Lower respiratory infections affect the airways and lungs, causing cough, phlegm, wheezing and shortness of breath, and are more likely to be serious.
How long do respiratory infections last?
Colds usually last 7 to 10 days. Flu symptoms improve in about a week but tiredness can last longer. A cough from acute bronchitis often lasts 2 to 3 weeks. See a doctor if symptoms last longer or get worse.
Do respiratory infections need antibiotics?
Most do not, because they are caused by viruses. Antibiotics are only helpful for bacterial infections such as strep throat, bacterial pneumonia and some sinus infections. Taking them unnecessarily causes side effects and resistance.
When should I see a doctor for a respiratory infection?
See a doctor for breathing difficulty, chest pain, high or prolonged fever, coughing up blood, symptoms lasting more than 10 days, or worsening after improving. Babies, older adults and people with chronic illness should be seen sooner.
Sources
This guide was written from current patient and clinical guidance, including:
- CDC: Respiratory illnesses; Antibiotic prescribing and use: common illnesses
- NICE: Respiratory tract infections (self-limiting): prescribing antibiotics (CG69)
- American Lung Association: Lung health and diseases
- World Health Organization: Acute respiratory infections
- MedlinePlus: Respiratory tract infections