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Upper respiratory tract infection

Topic: Medicine

 From HandWiki - Reading time: 14 min

Not to be confused with UTI.
Short description: Infection of the nose, sinuses, pharynx, larynx or trachea

Upper respiratory tract infection
Conducting passages
SpecialtyInfectious disease, Family medicine, Pediatrics, Otolaryngology
Frequency12.8 billion cases (2021)

An upper respiratory tract infection (URTI) is an illness caused by an acute infection, which involves the upper respiratory tract, including the nose, sinuses, pharynx, larynx or trachea.[1][2] This commonly includes nasal obstruction, sore throat, tonsillitis, pharyngitis, laryngitis, sinusitis, otitis media, and the common cold.[3]: 28  Most infections are viral in nature, and in other instances, the cause is bacterial.[4] URTIs can also be fungal or helminthic in origin, but these are less common.[5]: 443–445 


Classification

A URTI may be classified by the area inflamed. Rhinosinusitis or sinusitis affects the nose and paranasal sinuses, including frontal, ethmoid, maxillary, and sphenoid sinuses.[6] Pharyngitis refers to inflammation of the pharynx and/or tonsils. Similarly, epiglottitis inflames the epiglottis and surrounding supraglottic tissues.[6] Laryngitis affects the larynx and vocal cords.[6]

Signs and symptoms

Time line for cold symptoms

URTIs commonly present with a constellation of symptoms, including cough, sore throat, runny nose, nasal congestion, headache, low-grade fever, facial pressure, and sneezing. Early manifestations often include sore throat, sneezing, and malaise, which may improve within several days.[7] As the illness progresses, symptoms of nasal discharge and cough may appear.[7]

Color or consistency changes in mucous discharge to yellow, thick, or green are the natural course of viral URTI.[4] Most symptoms resolve within 7-10 days; however, cough can persist for several weeks in some individuals.[8]

Group A beta-hemolytic streptococcal pharyngitis/tonsillitis (strep throat) typically presents with a sudden onset of sore throat, pain with swallowing, and fever. It is less commonly associated with a cough and nasal congestion.[9]

Cause

Most URTIs are viral in origin; however, certain presentations may be caused by bacteria.[5]

Common viral pathogens include rhinovirus, adenovirus, influenza virus, parainfluenza, measles, respiratory syncytial virus (RSV), human metapneumovirus (HMPV), and coronaviruses such as SARS-CoV.[10]

Transmission of viral URTIs occurs through respiratory droplets, airborne particles, or direct contact with contaminated surfaces. The transmission routes can also be affected by other variables such as environment, crowding, and host factors.[10]

Up to 15% of acute pharyngitis cases may be caused by bacteria, most commonly Streptococcus pyogenes, a group A streptococcus in streptococcal pharyngitis ("strep throat").[11] Other bacterial causes include groups C and G beta-hemolytic streptococci and Corynebacterium diphtheriae.[12] Sexually transmitted infections have also emerged as causes of oral and pharyngeal infections.[13]

Pathophysiology

In terms of pathophysiology, rhinovirus infection resembles the immune response. The viruses do not cause damage to the cells of the upper respiratory tract, but rather cause changes in the tight junctions of epithelial cells. This allows the virus to gain access to tissues under the epithelial cells and initiate the innate and adaptive immune responses.[3]: 27 

Most symptoms of URTIs result from inflammatory mediators rather than viral injury itself. Nasal congestion occurs due to vasodilation of venous sinusoids within the nasal mucosa. Generalized symptoms such as headache, malaise, and muscle aches are mediated by the release of cytokines and prostaglandins during the immune response.[8]

Diagnosis

In most cases, URTIs are diagnosed clinically based on history and physical exam. Identification of the specific pathogen rarely alters management, except in circumstances where antibiotics or infection control is warranted.[14]

Diagnostic testing may be considered in select patients depending on illness severity, examination findings, epidemiological factors, and global/local disease burden.[8] When indicated, testing may include disease-specific rapid antigen detection tests or a viral respiratory panel.[8]

Many respiratory infections present with overlapping symptoms, and distinguishing among them may require careful clinical evaluation. Listed below are three common infections with overlapping symptoms.[6]

Seasonal allergies, Common Cold, Influenza: Symptom Comparison
Symptoms Allergy Common Cold (an URTI) Influenza (Flu)
Itchy, watery eyes Common Rare (conjunctivitis may occur with adenovirus) Soreness behind eyes, sometimes conjunctivitis
Nasal discharge Common Common[4] Common
Nasal congestion Common Common Sometimes
Sneezing Very common Very common[4] Sometimes
Sore throat Sometimes (post-nasal drip) Very common[4] Sometimes
Cough Sometimes Common (mild to moderate, hacking)[4] Common (dry cough, can be severe)
Headache Uncommon Rare Common
Fever Never Rare in adults, possible in children[4] Very common
37.8–38.9 °C (100–102 °F)(or higher in young children), lasting 3–4 days; may have chills
Malaise Sometimes Sometimes Very common
Fatigue, weakness Sometimes Sometimes Very common (can last for weeks, extreme exhaustion early in course)
Muscle pain Never Slight[4] Very common (often severe)

Prevention

Vaccination plays an important role in reducing the burden of certain upper respiratory infections.[15] Immunization against influenza viruses, measles, Streptococcus pneumoniae, Haemophilus influenzae, and Bordetella pertussis can reduce the incidence or severity of associated respiratory infections.[15]

Non-pharamacologic measures, particularly hand hygiene, are also effective in limiting transmission.[9]

Treatment

Upper respiratory infections deaths per million persons in 2012
  0
  1
  2
  3–29

Treatment comprises symptomatic support usually via analgesics for headache, sore throat, and muscle aches.[16] Moderate exercise in sedentary subjects with a naturally acquired URTI probably does not alter the overall severity and duration of the illness.[17] No randomized trials have been conducted to ascertain benefits of increasing fluid intake.[18]

Antibiotics

Although most URTIs are viral and self-limiting, antibiotics are frequently overprescribed. Unnecessary antibiotic use contributes to antimicrobial resistance, increased healthcare costs, and possible adverse drug reactions.[6]

Health authorities have been strongly encouraging physicians to decrease the prescribing of antibiotics to treat common URTIs because antibiotic usage does not significantly reduce recovery time for these viral illnesses.[19] Decreased antibiotic usage may help prevent drug-resistant bacteria. A 2017 systematic review found three interventions which were probably effective in reducing antibiotic use for acute respiratory infections: C-reactive protein testing, procalcitonin-guided management, and shared decision-making between physicians and patients.[20] Others have advocated a delayed antibiotic approach to treating URTIs, which seeks to reduce the consumption of antibiotics while attempting to maintain patient satisfaction. A Cochrane review of 11 studies and 3,555 participants explored antibiotics for respiratory tract infections. It compared delaying antibiotic treatment to either starting them immediately or to no antibiotics. Outcomes were mixed depending on the respiratory tract infection; symptoms of acute otitis media and sore throat were modestly improved with immediate antibiotics with minimal difference in complication rate. Antibiotic usage was reduced when antibiotics were only used for ongoing symptoms and maintained patient satisfaction at 86%.[21] In a trial involving 432 children with a URTI, amoxicillin was no more effective than placebo, even for children with more severe symptoms such as fever or shortness of breath.[22][23]

Prescribing antibiotics for laryngitis is not a suggested practice either.[19] The antibiotics penicillin V and erythromycin are not effective for treating acute laryngitis.[19] Erythromycin may improve voice disturbances after a week and cough after 2 weeks, but any modest subjective benefit is not greater than the adverse effects, cost, and the risk of bacteria developing resistance to the antibiotics.[19]

While not recommended for viral URTIs, antibiotic usage is supported in most bacterial URTI cases such as acute otitis media, group A beta-hemolytic streptococcal pharyngitis, epiglottitis, and a small percentage of rhinosinusitis cases. In children with acute otitis media, amoxicillin is the first-line treatment. Treatment of group A beta-hemolytic streptococcal pharyngitis includes penicillin V or amoxicillin. For acute bacterial sinusitis, guidelines recommend targeting likely organisms with amoxicillin or amoxicillin/clavulanate and using the shortest effective treatment duration. Imaging is generally reserved for recurrent, severe, or unclear cases.[6]

Cough medicine

There is limited evidence supporting the effectiveness of over-the-counter cough medications for reducing coughing in adults or children.[24] In addition, according to the American Academy of Pediatrics, the use of cough medicine to relieve cough symptoms should be avoided in children under 4 years old, and the safety is questioned for children under 6 years old.[8][25]

Decongestants

Disability-adjusted life year for URTIs per 100,000 inhabitants in 2002:[26]
  no data
  less than 10
  10–30
  30–60
  60–90
  90–120
  120–150
  150–180
  180–210
  210–240
  240–270
  270–300
  more than 300

According to a Cochrane review, a single oral dose of nasal decongestant in the common cold is modestly effective for the short-term relief of congestion in adults; however, data on the use of decongestants in children are insufficient. Therefore, decongestants are not recommended for use in children under 12 years of age with the common cold.[21] Oral decongestants are also contraindicated in patients with hypertension, coronary artery disease, and history of bleeding strokes.[27][28]

Mucolytics

Mucolytics such as N-acetylcysteine, ambroxol, carbocystine, and bromhexine may help reduce viscosity and provide symptomatic relief in some patients.[29] Acetylcysteine is considered to be safe for the children older than 2 years.[30]

Alternative medicine

The use of vitamin C in the inhibition and treatment of upper respiratory infections has been suggested since the initial isolation of vitamin C in the 1930s. Evidence regarding the use of vitamin C in these capacities remain mixed; however, some studies suggest that when vitamin C is taken prophylactically, it can reduce the duration of the common cold by 8% in adults and 13% in children.[31] Other studies have also shown that vitamin C supplementation can decrease severe forms of the common cold by 15%.[32]

Zinc supplementation has been shown in some studies to reduce symptom duration in adults by 2 days, though effects on symptom severity are less consistent.[33][34]

Cool mist humidifiers, sterile saline nasal drops, and sprays can help alleviate symptoms in some people.[8]

Honey may also be used to reduce cough symptoms; however, care should be taken to avoid giving this to children under the age of 1 due to botulinum risk.[8]

Complications

Potential complications include: sinusitis, ear infection, mastoiditis, and progression to lower respiratory tract infection.[8]

Epidemiology

URTIs represent the most common infectious illnesses worldwide. Global burden studies estimate billions of cases annually, with significant variation by year and region.[35][36]

Due to the high frequency of these infections, URTIs contribute substantially to healthcare utilization, school and workplace absenteeism, and economic burden globally.[8][36]

Seasonal patterns are also well established. The common cold is more prevalent in the fall and spring, whereas RSV, influenza, and certain coronaviruses typically peak during the winter months.[8]

Children under the age of five are most likely to be affected by URTIs globally.[35] Children typically have two to nine viral respiratory illnesses per year.[4]

Dietary research

Weak evidence suggests that probiotics may be better than a placebo treatment or no treatment for preventing upper respiratory tract infections.[37]

See also

References

  1. ↑ "Viral Upper Respiratory Tract Infections" (in en). Viral Infections in Children, Volume II. Cham: Springer International Publishing. 2017. pp. 1–25. doi:10.1007/978-3-319-54093-1_1. ISBN 978-3-319-54093-1. 
  2. ↑ (in en) Infectious Diseases of the Respiratory Tract. Cambridge University Press. 1998-02-12. p. 453. ISBN 978-0-521-40554-6. https://books.google.com/books?id=-X0W5ryclIgC. Retrieved 1 July 2021. 
  3. ↑ 3.0 3.1 Pulmonary infection. Cham: Springer. 2015. ISBN 978-3-319-17458-7. 
  4. ↑ 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 "Rhinitis Versus Sinusitis in Children". Centers for Disease Control and Prevention. https://www.cdc.gov/getsmart/community/materials-references/print-materials/hcp/child-rhin-vs-sinus.pdf.  Public Domain This article incorporates text from this source, which is in the public domain.
  5. ↑ 5.0 5.1 * Control of communicable diseases manual: an official report of the American Public Health Association.. APHA Press, the American Public Health Association. 2015. ISBN 978-0-87553-018-5. 
  6. ↑ 6.0 6.1 6.2 6.3 6.4 6.5 Denise K. C. Sur; Plesa, Monica L. (2022-12). "Antibiotic Use in Acute Upper Respiratory Tract Infections". American Family Physician. 106 (6). ISSN 1532-0650. Archived from the original on 2025-10-18.
  7. ↑ 7.0 7.1 Kuchar, E.; Miśkiewicz, K.; Nitsch-Osuch, Aneta; Szenborn, L. (2015). "Pathophysiology of Clinical Symptoms in Acute Viral Respiratory Tract Infections". Pulmonary Infection. Advances in Experimental Medicine and Biology. 857. pp. 25–38. doi:10.1007/5584_2015_110. ISBN 978-3-319-17457-0. 
  8. ↑ 8.00 8.01 8.02 8.03 8.04 8.05 8.06 8.07 8.08 8.09 PMC, Europe. "Europe PMC" (in en). https://europepmc.org/article/NBK/nbk532961#article-30801.r1. 
  9. ↑ 9.0 9.1 DeGeorge, Katharine C.; Ring, Daniel J.; Dalrymple, Sarah N. (2019-09-01). "Treatment of the Common Cold" (in en-US). American Family Physician 100 (5): 281–289. https://www.aafp.org/pubs/afp/issues/2019/0901/p281.html. 
  10. ↑ 10.0 10.1 Kutter, Jasmin S; Spronken, Monique I; Fraaij, Pieter L; Fouchier, Ron AM; Herfst, Sander (2018-02-01). "Transmission routes of respiratory viruses among humans". Current Opinion in Virology. Emerging viruses: intraspecies transmission • Viral Immunology 28: 142–151. doi:10.1016/j.coviro.2018.01.001. ISSN 1879-6257. PMID 29452994. Bibcode: 2018COVir..28..142K. 
  11. ↑ "Acute pharyngitis". The New England Journal of Medicine 344 (3): 205–11. January 2001. doi:10.1056/nejm200101183440308. PMID 11172144. 
  12. ↑ "Pharyngitis" (in en-US), Principles and Practice of Pediatric Infectious Disease (W.B. Saunders): 206–213, 2008-01-01, doi:10.1016/B978-0-7020-3468-8.50035-3, ISBN 978-0-7020-3468-8 
  13. ↑ "Human papillomavirus (HPV) and Oropharyngeal Cancer, Sexually Transmitted Diseases". Centers for Disease Control and Prevention. 2016-11-04. https://www.cdc.gov/std/hpv/STDFact-HPVandOropharyngealCancer.htm. 
  14. ↑ Guibas, George V.; Papadopoulos, Nikolaos G. (2017), Green, Robin J., ed., "Viral Upper Respiratory Tract Infections" (in en), Viral Infections in Children, Volume II (Cham: Springer International Publishing): 1–25, doi:10.1007/978-3-319-54093-1_1, ISBN 978-3-319-54093-1 
  15. ↑ 15.0 15.1 Bianchini, Sonia; Argentiero, Alberto; Camilloni, Barbara; Silvestri, Ettore; Alunno, Anna; Esposito, Susanna (2019-11-01). "Vaccination against Paediatric Respiratory Pathogens". Vaccines 7 (4): 168. doi:10.3390/vaccines7040168. ISSN 2076-393X. PMID 31683882. 
  16. ↑ "Common Cold: Treatments and Drugs". Mayo Clinic. http://www.mayoclinic.com/health/common-cold/DS00056/DSECTION=treatments-and-drugs. 
  17. ↑ "Effect of exercise on upper respiratory tract infection in sedentary subjects". British Journal of Sports Medicine 37 (4): 304–6. August 2003. doi:10.1136/bjsm.37.4.304. PMID 12893713. 
  18. ↑ ""Drink plenty of fluids": a systematic review of evidence for this recommendation in acute respiratory infections". The BMJ 328 (7438): 499–500. February 2004. doi:10.1136/bmj.38028.627593.BE. PMID 14988184. 
  19. ↑ 19.0 19.1 19.2 19.3 "Antibiotics for acute laryngitis in adults". The Cochrane Database of Systematic Reviews 2015 (5). May 2015. doi:10.1002/14651858.CD004783.pub5. PMID 26002823. 
  20. ↑ "Clinician-targeted interventions to influence antibiotic prescribing behaviour for acute respiratory infections in primary care: an overview of systematic reviews". The Cochrane Database of Systematic Reviews 2019 (9). September 2017. doi:10.1002/14651858.CD012252.pub2. PMID 28881002. 
  21. ↑ 21.0 21.1 "Immediate versus delayed versus no antibiotics for respiratory infections". The Cochrane Database of Systematic Reviews 2023 (10). October 2023. doi:10.1002/14651858.CD004417.pub6. PMID 37791590. 
  22. ↑ "Antibiotics for lower respiratory tract infection in children presenting in primary care: ARTIC-PC RCT". Health Technology Assessment 27 (9): 1–90. June 2023. doi:10.3310/DGBV3199. PMID 37436003. 
  23. ↑ "Antibiotics make little difference to children's chest infections". NIHR Evidence (UK: National Institute for Health and Care Research (NIHR)). 27 November 2023. doi:10.3310/nihrevidence_60506. https://evidence.nihr.ac.uk/alert/antibiotics-make-little-difference-to-childrens-chest-infections/. Retrieved 4 December 2023. 
  24. ↑ "Over-the-counter (OTC) medications for acute cough in children and adults in community settings". The Cochrane Database of Systematic Reviews 2014 (11). November 2014. doi:10.1002/14651858.CD001831.pub5. PMID 25420096. 
  25. ↑ "Cough in the pediatric population". The Journal of Pediatrics 156 (3): 352–8. March 2010. doi:10.1016/j.jpeds.2009.12.004. PMID 20176183. 
  26. ↑ "Mortality and Burden of Disease Estimates for WHO Member States in 2002" (xls). World Health Organization. 2002. https://www.who.int/entity/healthinfo/statistics/bodgbddeathdalyestimates.xls. 
  27. ↑ "Disorders related to cold and allergy". Handbook of Nonprescription Drugs (14th ed.). Washington, DC: American Pharmacists Association. 2004. pp. 239–269. ISBN 978-1-58212-050-8. OCLC 56446842. 
  28. ↑ "Common cold". Nonprescription Drug Therapy: Guiding Patient Self-care (1st ed.). St Louis, MO: Facts & Comparisons. 2002. pp. 743–769. ISBN 978-1-57439-146-6. OCLC 52895543. 
  29. ↑ Scaglione, Francesco; Petrini, Orlando (2019). "Mucoactive Agents in the Therapy of Upper Respiratory Airways Infections: Fair to Describe Them Just as Mucoactive?". Clinical Medicine Insights. Ear, Nose and Throat 12. doi:10.1177/1179550618821930. ISSN 1179-5506. PMID 30670922. 
  30. ↑ "Acetylcysteine and carbocysteine for acute upper and lower respiratory tract infections in paediatric patients without chronic broncho-pulmonary disease". The Cochrane Database of Systematic Reviews (5). May 2013. doi:10.1002/14651858.CD003124.pub4. PMID 23728642. 
  31. ↑ Rondanelli, Mariangela; Miccono, Alessandra; Lamburghini, Silvia; Avanzato, Ilaria; Riva, Antonella; Allegrini, Pietro; Faliva, Milena Anna; Peroni, Gabriella et al. (2018). "Self-Care for Common Colds: The Pivotal Role of Vitamin D, Vitamin C, Zinc, and Echinacea in Three Main Immune Interactive Clusters (Physical Barriers, Innate and Adaptive Immunity) Involved during an Episode of Common Colds-Practical Advice on Dosages and on the Time to Take These Nutrients/Botanicals in order to Prevent or Treat Common Colds". Evidence-Based Complementary and Alternative Medicine 2018. doi:10.1155/2018/5813095. ISSN 1741-427X. PMID 29853961. 
  32. ↑ Hemilä, Harri; Chalker, Elizabeth (2023-12-11). "Vitamin C reduces the severity of common colds: a meta-analysis" (in en). BMC Public Health 23 (1). doi:10.1186/s12889-023-17229-8. ISSN 1471-2458. PMID 38082300. 
  33. ↑ Hunter, Jennifer; Arentz, Susan; Goldenberg, Joshua; Yang, Guoyan; Beardsley, Jennifer; Myers, Stephen P.; Mertz, Dominik; Leeder, Stephen (2021-10-01). "Zinc for the prevention or treatment of acute viral respiratory tract infections in adults: a rapid systematic review and meta-analysis of randomised controlled trials" (in en). BMJ Open 11 (11). doi:10.1136/bmjopen-2020-047474. ISSN 2044-6055. PMID 34728441. 
  34. ↑ Saigal, Pooja MD; Hanekom, Damian MD. Does zinc improve symptoms of viral upper respiratory tract infection?. Evidence-Based Practice 23(1):p 37-39, January 2020. | DOI: 10.1097/EBP.0000000000000489
  35. ↑ 35.0 35.1 Jin, Xuting; Ren, Jiajia; Li, Ruohan; Gao, Ya; Zhang, Haoying; Li, Jiamei; Zhang, Jingjing; Wang, Xiaochuang et al. (2021-07-01). "Global burden of upper respiratory infections in 204 countries and territories, from 1990 to 2019" (in English). eClinicalMedicine 37. doi:10.1016/j.eclinm.2021.100986. ISSN 2589-5370. PMID 34386754. 
  36. ↑ 36.0 36.1 Sirota, Sarah Brooke; Doxey, Matthew C.; Dominguez, Regina-Mae Villanueva; Bender, Rose Grace; Vongpradith, Avina; Albertson, Samuel B.; Novotney, Amanda; Burkart, Katrin et al. (2025-01-01). "Global, regional, and national burden of upper respiratory infections and otitis media, 1990–2021: a systematic analysis from the Global Burden of Disease Study 2021" (in English). The Lancet Infectious Diseases 25 (1): 36–51. doi:10.1016/S1473-3099(24)00430-4. ISSN 1473-3099. PMID 39265593. 
  37. ↑ "Probiotics for preventing acute upper respiratory tract infections". The Cochrane Database of Systematic Reviews 2022 (8). August 2022. doi:10.1002/14651858.CD006895.pub4. PMID 36001877. 
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