Upper respiratory tract infection

Last updated: September 23, 2024

Summary

Upper respiratory tract infections (URTIs) involve structures at or above the vocal cords, e.g., the nasal cavity, sinuses, pharynx, and/or larynx. URTIs include the common cold, acute rhinosinusitis, pharyngitis, laryngitis, influenza, croup, and COVID-19. Most URTIs are caused by viruses such as the rhinovirus. URTIs more commonly occur in the fall and winter and are especially common in children. Typical clinical manifestations include rhinorrhea, nasal congestion, sore throat, and cough. Diagnosis is generally clinical, although diagnostic testing may be performed to assess for specific infections (e.g., influenza, COVID-19, group A streptococcal pharyngitis). In most cases, treatment is supportive, with symptoms typically resolving within 14 days. Antibiotics are not indicated unless there is a confirmed bacterial infection.

Epidemiology

More commonly occur in the fall and winter ^[1]
Higher incidence in children than adults ^[2]
- Children: 6–10 per year
- Adults: 2–4 per year

Epidemiological data refers to the US, unless otherwise specified.

Etiology

Most URTIs are caused by viruses. ^[3]

Viral

Bacterial

Many of the pathogens that cause URTI can also cause lower respiratory tract infections (LRTIs). ^[1]^[3]

Clinical evaluation

Focused history

Symptom duration: typically ≤ 14 days ^[2]
Common features of URTI ^[2]
- Sore throat
- Nasal congestion
- Rhinorrhea (with or without purulence)
- Cough
- Fever (esp. among pediatric patients)
Exposures
- Recent travel history
- Contact with infectious individuals in the past week ^[2]
Vaccination status: e.g., COVID-19 vaccination, Hib vaccination, influenza vaccination
Targeted review of systems: e.g., HEENT, pulmonary

Focused physical examination

Sinus, nose, and throat examination
Pulmonary examination including assessment for pathological breath sounds

Fever is more common among pediatric than adult patients, and typically lasts for 2–3 days. ^[2]

Initial management

Outpatient treatment of URTI is appropriate for most patients; complications are rare.

Approach

Check vital signs.
Urgently evaluate patients with red flags for URTI to assess for:
- Life-threatening causes of URTI
- Complications, e.g., secondary bacterial infection
Consult ENT or anesthesia immediately if patients have signs of airway compromise or signs of respiratory distress.

Red flags for URTI

Worsening symptoms after an initial period of improvement ^[4]
Trismus, drooling, muffled voice ^[5]
Signs of respiratory distress ^[6]^[7]
Clinical features of sepsis ^[7]

Life-threatening causes of URTI

Pertussis in infants < 6 months of age
Epiglottitis
Severe COVID-19
Severe influenza

Diagnosis

Most URTIs can be diagnosed clinically. Consider diagnostic studies in selected patients.

Nonspecific laboratory studies

Routine studies: to support the diagnosis and/or determine disease severity
- CBC may show:
  - Lymphopenia, e.g., in COVID-19 ^[8]
  - Lymphocytosis, e.g., in pertussis, influenza, infectious mononucleosis ^[7]^[9]^[10]
- ESR and CRP may be elevated. ^[11]
- BMP and liver chemistries may show signs of end-organ damage in severe disease (e.g., severe COVID-19).
Blood cultures: Consider in severe disease (e.g., epiglottitis) to evaluate for concurrent bacteremia.
ABG: Obtain in patients with signs of respiratory distress. ^[12]^[13]

Disease-specific laboratory studies

Consider specific studies based on clinical suspicion to support treatment and/or disposition decisions.

Rapid strep test: : suspected acute bacterial tonsillopharyngitis
Heterophile antibody test: : suspected infectious mononucleosis ^[10]
Disease-specific NAATs (e.g., PCR) in patients with:
- Indications for influenza testing ^[7]
- COVID-19 symptoms and/or known exposure ^[14]
- Suspected pertussis
- Risk factors for severe RSV infection
Respiratory viral panel
- Can differentiate between different viral etiologies of URTIs (e.g., influenza, parainfluenza, RSV)
- Not routinely indicated
- May be considered in certain patients, e.g.:
  - Those with an atypical presentation
  - If there is diagnostic uncertainty in suspected croup

Modified Centor score for group A streptococcal infection

Imaging

Consider imaging to support the diagnosis, determine disease severity, and/or evaluate for complications.

Chest imaging (CXR or CT scan): to evaluate for pneumonia ^[15]^[16]
Neck imaging
- Anterior-posterior x-ray neck: to evaluate for croup ^[17]
- Lateral x-ray neck: to evaluate for epiglottitis in children ^[18]
- CT neck with IV contrast ^[19]^[20]^[21]
  - Adults: to rule out differential diagnoses in patients with suspected epiglottitis
  - Children: to rule out differential diagnoses and/or assess for congenital abnormalities in croup
CT maxillofacial with or without IV contrast: in patients with red flags for rhinosinusitis

Common causes of URTIs

Common causes of URTIs ^[1]^[3]^[6]^[22]
Condition	Most common pathogens	Clinical features	Diagnostic testing	Treatment
Common cold ^[23]	Rhinovirus	Onset: gradual Fever: rare (low-grade if present) Nasal congestion, rhinorrhea, sneezing Sore throat, cough No prominent localizing features	Clinical diagnosis	Supportive care
Influenza ^[7]	Influenza virus	Onset: abrupt Fever: common, typically high Chills, myalgias Sore throat, dry cough	A clinical diagnosis is possible during influenza season. Consider a rapid molecular assay or RT-PCR for diagnostic confirmation. See “Diagnostics for influenza.”	Supportive care Antiviral therapy for influenza (e.g., oseltamivir) in selected cases (e.g., severe illness)
COVID-19 ^[24]	SARS-CoV-2	Onset: variable Fever: common Cough, shortness of breath Loss of smell and/or taste	RT-PCR (gold standard) and/or antigen testing See “COVID-19 testing.”	Supportive care For patients with severe COVID-19 and/or risk factors for severe COVID-19, pharmacotherapy may include: Antiviral therapy (e.g., remdesivir) Glucocorticoids (e.g., dexamethasone)
Acute rhinosinusitis ^[25]	Rhinovirus S. pneumoniae H. influenzae	Onset: gradual Fever: present in ∼ 50% of cases Facial pain and pressure with tenderness to palpation Nasal congestion, rhinorrhea Opacification of sinuses on transillumination	Clinical diagnosis based on diagnostic criteria for acute rhinosinusitis	Supportive care (e.g., intranasal steroids) ^[1] Antibiotics (e.g., amoxicillin, amoxicillin/clavulanate); see “Antibiotic treatment in acute bacterial rhinosinusitis.”
Acute tonsillopharyngitis ^[26]	Rhinovirus S. pyogenes	Viral Onset: gradual Fever: rare (low-grade if present) Rhinorrhea, cough, hoarseness Bacterial Onset: abrupt Fever: common, typically high Sore throat, painful swallowing Inflammation of the pharynx and tonsils No cough	Primarily a clinical diagnosis Rapid strep test and/or throat culture if Centor score is ≥ 2 See “Diagnostics for acute tonsillitis and pharyngitis.”	Supportive care Antibiotics (e.g., penicillin, amoxicillin) for patients with confirmed GAS infection
Laryngitis ^[2]	Rhinovirus S. pneumoniae H. influenzae	Hoarseness Barking cough	Primarily a clinical diagnosis Laryngoscopy for patients with red flags in hoarseness	Supportive care (e.g., hydration, air humidification) Vocal rest
Epiglottitis ^[6]	H. influenzae S. pneumoniae S. pyogenes	Onset: abrupt in children; gradual in adults Fever: common, typically high Dysphagia and drooling Respiratory distress Muffled voice Tripod position	Primarily a clinical diagnosis Visualization of the epiglottis (e.g., with pharyngoscopy or laryngoscopy) Imaging (e.g., lateral x-ray neck) if there is diagnostic uncertainty	Antibiotics (e.g., cefotaxime, ampicillin/sulbactam) Glucocorticoids (e.g., dexamethasone) Airway management in epiglottitis
Croup ^[1]	Parainfluenza virus	Onset: gradual Fever: common, low-grade Barking cough (worse at night) Stridor	Primarily a clinical diagnosis Consider imaging (e.g., anterior-posterior x-ray neck) if there is diagnostic uncertainty. See “Diagnostics of croup.”	Oxygen therapy Glucocorticoids (e.g., dexamethasone) Nebulized epinephrine Airway management See “Acute management checklist for croup.”
Pertussis ^[9]	B. pertussis	Onset: gradual Fever: rare (low-grade if present) Paroxysms of whooping cough Rhinorrhea, myalgias, sore throat (rare)	Culture or PCR of nasopharyngeal specimen within the first 2 weeks of infection ^[27] See “Diagnostics for pertussis.”	Antibiotics (e.g., azithromycin) See “Treatment of pertussis.”
Infectious mononucleosis ^[2]	Epstein-Barr virus	Common in adolescents and young adults Rare in adults aged > 40 years Onset: gradual Fever: common Marked lymphadenopathy Malaise Splenomegaly Sore throat, exudative pharyngitis	EBV serology: most reliable laboratory study Monospot test CBC with differential	Supportive care Avoidance of strenuous exercise and contact sports

Modified Centor score for group A streptococcal infection

Treatment

General principles ^[1]^[22]

Recommend rest and adequate hydration (e.g., 6–10 glasses of fluid a day).
Advise patients to avoid smoking and alcohol use.
Offer symptomatic treatment as needed.
Provide specific treatment if indicated, e.g.:
- Treatment of influenza
- Management of COVID-19
- Antibiotics only for disease-specific indications (e.g., GAS pharyngitis)
Counsel on return precautions.

Do not prescribe antibiotics without confirmation of a bacterial infection, as antibiotics do not treat viral infections and may cause harm, e.g., drug hypersensitivity reaction, C. difficile infection. ^[6]

Symptomatic treatment ^[1]^[22]^[28]

General
- Zinc (e.g., zinc acetate or gluconate lozenges) and probiotics (e.g., containing Lactobacillus casei) have been shown to shorten symptom duration. ^[29]^[30]
- Oral antihistamine/decongestant combinations may improve symptoms but can cause adverse effects, e.g., dry mouth and dizziness.
Rhinorrhea or sinus congestion
- Elevate the head of the bed to improve sinus drainage.
- Apply warm packs to the face for 5–10 minutes 3 times a day for facial pain. ^[1]
- Nasal saline irrigation
- Intranasal decongestants, e.g., oxymetazoline
Pain or fever: analgesics, e.g., ibuprofen and/or acetaminophen
Cough: nonpharmacological measures may be beneficial, e.g., honey ^[22]^[31]

Antitussives (e.g., codeine, dextromethorphan) and expectorants (e.g., guaifenesin) are not effective for URTI-associated cough. ^[28]

Return precautions ^[2]

Dyspnea
Chest pain
Productive cough
Fever > 38.9^oC (102^oF)
Severe headache or facial pain
Dizziness, confusion
Symptom duration > 14 days (other than cough)

Differential diagnoses

Infectious
- LRTIs, e.g., pneumonia
- Acute HIV infection
- Measles
Noninfectious

The differential diagnoses listed here are not exhaustive.

Complications

Most URTIs are mild and self-limited and rarely cause complications. ^[1]

LRTIs
Otitis media
Secondary bacterial infection
See also the respective articles for complications of specific causes of URTI, e.g.:
- Sinusitis complications
- Pertussis complications

We list the most important complications. The selection is not exhaustive.

Prevention

Educate patients and caregivers on respiratory hygiene and hand hygiene.
Recommend regularly cleaning and disinfecting surfaces that are touched often, e.g., door handles.
Advise patients to stay at home until both:
- Afebrile for 24 hours without the use of antipyretics
- Symptoms are improving
Ensure age-appropriate immunizations are up-to-date, including seasonal vaccines, e.g.:

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