eMedicine Specialties > Emergency Medicine > Ear, Nose, & Throat


Author: John R Acerra, MD, Assistant Professor, Department of Emergency Medicine, Albert Einstein College of Medicine; Associate Director, International Emergency Medicine Fellowship, North Shore - LIJ Health System
Contributor Information and Disclosures

Updated: Aug 10, 2009



Pharyngitis is defined as an infection or irritation of the pharynx and/or tonsils. The etiology is usually infectious, with most cases being of viral origin. These cases are benign and self-limiting for the most part. Bacterial causes of pharyngitis are also self-limiting, but are concerning because of suppurative and nonsuppurative complications. Other causes include allergy, trauma, toxins, and neoplasia.1

<EM>Streptococcus pyogenes</EM> at 100X magnifica...

Streptococcus pyogenes at 100X magnification.

<EM>Streptococcus pyogenes</EM> at 100X magnifica...

Streptococcus pyogenes at 100X magnification.

Posterior pharynx with petechiae and exudates in ...

Posterior pharynx with petechiae and exudates in a 12-year-old girl. Both the rapid antigen detection test and throat culture were positive for group A beta-hemolytic streptococci.

Posterior pharynx with petechiae and exudates in ...

Posterior pharynx with petechiae and exudates in a 12-year-old girl. Both the rapid antigen detection test and throat culture were positive for group A beta-hemolytic streptococci.

The main ED concerns with pharyngitis are to rule out more serious conditions, such as epiglottitis or peritonsillar abscess, and to diagnose group A beta-hemolytic streptococcal (GAS) infections. Airway obstruction is also of utmost importance for the ED physician treating pharyngitis.


With infectious pharyngitis, bacteria or viruses may directly invade the pharyngeal mucosa, causing a local inflammatory response. Other viruses, such as rhinovirus and coronavirus, can cause irritation of pharyngeal mucosa secondary to nasal secretions.2

Streptococcal infections are characterized by local invasion and release of extracellular toxins and proteases. In addition, M protein fragments of certain serotypes of GAS are similar to myocardial sarcolemma antigens and are linked to rheumatic fever and subsequent heart valve damage. Acute glomerulonephritis may result from antibody-antigen complex deposition in glomeruli.3


United States

Children experience more than 5 upper respiratory infections (URIs) per year and an average of one streptococcal infection every 4 years. The occurrence in adults is about one half that rate. The most significant bacterial agent causing pharyngitis in both adults and children is GAS infection (Streptococcus pyogenes), and the most common viruses are rhinovirus and adenovirus. GAS is most prevalent in late fall through early spring.1


The incidence of pharyngitis is higher internationally. Antibiotic resistance may be more prevalent in some countries because of overprescription of antibiotics. Note, however, that despite this, there has never been a documented case of GAS resistant to penicillin anywhere in the world.4


  • In the developing world, an estimated 20 million people are affected by acute rheumatic fever and rheumatic heart disease, making this the leading cause of cardiac death during the first 5 decades of life. This incidence of rheumatic heart disease is dramatically lower in most developed countries, but localized outbreaks have occurred in the Western world. Despite this, new cases of rheumatic heart disease in the United States are extremely rare.5
  • Other sequelae of streptococcal pharyngitis include acute glomerulonephritis, peritonsillar abscess, and toxic shock syndrome.
  • Mortality from pharyngitis is rare but may result from one of its complications, most notably airway obstruction.


Pharyngitis occurs with much greater frequency in the pediatric population. Approximately 15-30% of pharyngitis cases among school-aged children in the cooler months are due to GAS. Only 10% of adult cases of pharyngitis are due to GAS.1

  • The peak incidence of bacterial and viral pharyngitis occurs in the school-aged child aged 4-7 years.
  • Pharyngitis, especially GAS infection, is rare in children younger than 3 years.
  • Mycoplasma pneumoniae, Chlamydia pneumoniae, and Arcanobacterium haemolyticus are other bacterial causes of pharyngitis, but these pathogens are rare. Antibiotics covering atypical pathogens should not routinely be used to treat pharyngitis.2



Viral and bacterial causes of pharyngitis are similar, and the differentiation of the etiology is difficult based on history and physical examination alone. Despite this, classic presentations are described below.

  • GAS infection is most common in children aged 4-7 years.
  • Sudden onset is consistent with a GAS pharyngitis. Pharyngitis following several days of coughing or rhinorrhea is more consistent with a viral etiology.
  • Person has been in contact with others diagnosed with GAS or rheumatic fever.
  • Headache is consistent with GAS infection.
  • Cough is not usually associated with GAS infection.
  • Vomiting is associated with GAS infection but may be present in other types of pharyngitis.
  • A history of recent orogenital contact suggests the possibility of gonococcal pharyngitis.
  • A history of rheumatic fever is important when considering treatment.
The Centor criteria have been used in the past as a way to diagnose and treat GAS pharyngitis.6 These include the following:
  • Fever
  • Anterior cervical lymphadenopathy
  • Tonsillar exudate
  • Absence of cough
One point is awarded for each of the criteria met, with patients scoring 0-1 unlikely to have GAS infection and patients with a score of 4 more likely to have GAS. A clinical diagnosis of GAS infection using these criteria can result in an overestimation of the incidence of streptococcal pharyngitis, as many bacterial and viral cases of pharyngitis can be indistinguishable on clinical grounds. This can lead to an overtreatment of pharyngitis with antibiotics.7 In adults, the positive predictive value of the Centor criteria for predicting GAS pharyngitis is around 40% if 3 criteria are met, and about 50% if 4 criteria are met.8 These criteria should not be used alone to guide antibiotic therapy for pharyngitis in adults.


  • Airway patency must be assessed and addressed first.
  • Temperature: Fever is usually absent or low-grade in viral pharyngitis, but fever is not reliable to differentiate viral or bacterial etiologies.
  • Hydration status: Oral intake usually is compromised because of odynophagia; therefore, various degrees of dehydration result.
  • Head, ears, eyes, nose, and throat (HEENT)
    • Conjunctivitis may be seen in association with adenovirus.
    • Scleral icterus may be seen with infectious mononucleosis.
    • Rhinorrhea usually is associated with a viral cause.
    • Tonsillopharyngeal/palatal petechiae are seen in GAS infections and infectious mononucleosis.
    • A tonsillopharyngeal exudate may be seen in streptococcal infectious mononucleosis and occasionally in M pneumoniae, C pneumoniae, A haemolyticus, adenovirus, and herpesvirus infections. Therefore, exudate does not differentiate viral and bacterial causes.
    • Oropharyngeal vesicular lesions are seen in coxsackievirus and herpesvirus. Concomitant vesicles on the hands and feet are associated with coxsackievirus (hand-foot-and-mouth disease).
  • Lymphadenopathy: Tender anterior cervical nodes are consistent with streptococcal infection, whereas generalized adenopathy is consistent with infectious mononucleosis or the acute lymphoglandular syndrome of HIV infection.
  • Cardiovascular: Murmurs should be documented in an acute episode of pharyngitis to monitor for potential rheumatic fever.
  • Pulmonary: Pharyngitis and lower respiratory tract infections are more consistent with M pneumoniae or C pneumoniae, particularly when a persistent nonproductive cough is present.
  • Abdomen: Hepatosplenomegaly can be found in infectious mononucleosis infection.
  • Skin
    • A sandpapery scarlatiniform rash is seen in GAS infection (see Scarlet Fever).9
    • Maculopapular rashes are seen with various viral infections and with infectious mononucleosis empirically treated with penicillin.


  • Bacterial pharyngitis
    • Group A beta-hemolytic streptococci: The classic clinical picture includes a fever, temperature of greater than 101.5°F; tonsillopharyngeal erythema and exudate; swollen, tender anterior cervical adenopathy; headache; emesis in children; palatal petechiae; midwinter to early spring season; and absent cough or rhinorrhea.9
    • Group C, G, and F streptococci may be indistinguishable clinically from GAS infection. Acute glomerulonephritis is an extremely unusual complication of group C streptococcal pharyngitis, but a relationship between group G streptococcal pharyngitis and acute glomerulonephritis has not be established. Acute rheumatic fever has not been described as a complication of either. They may be associated with food-borne outbreaks. The benefit of antibiotic therapy with these types of streptococci is unproven at this time.5
    • Arcanobacterium (Corynebacterium) haemolyticus is more common in young adults and is very similar to GAS infection, including a similar scarlatiniform rash. Patients often have a cough. Occasional outbreaks have been reported.
    • M pneumoniae in young adults presents with headache, pharyngitis, and lower respiratory symptoms. Approximately 75% of patients have a cough, which is distinctive from GAS infection.
    • C pneumoniae has a clinical picture similar to that of M pneumoniae. Pharyngitis usually precedes the pulmonary infection by about 1-3 weeks.
    • Neisseria gonorrhoeae is a rare cause of pharyngitis. A careful history is important since infection usually follows orogenital contact. It may be associated with severe systemic infection.
    • Corynebacterium diphtheriae is rare in the United States. A foul-smelling gray-white pharyngeal membrane may result in airway obstruction.
  • Viral pharyngitis3
    • Adenovirus: The distinguishing feature of an adenovirus infection is conjunctivitis associated with pharyngitis (pharyngoconjunctival fever). It is the most common etiology in children younger than 3 years.
    • Herpes simplex: Vesicular lesions (herpangina), especially in young children, are the hallmark. In older patients, pharyngitis may be indistinguishable from GABHS infection.
    • Coxsackieviruses A and B: These infections present similarly to herpes simplex, and vesicles may be present. If vesicles are whitish and nodular, it is known as lymphonodular pharyngitis. Coxsackievirus A16 may cause hand-foot-and-mouth disease, which presents with 4- to 8-mm oropharyngeal ulcers and vesicles on the hands and feet, and, occasionally, on the buttocks. The oropharyngeal ulcers and vesicles resolve within 1 week.
    • Epstein-Barr virus (EBV): Clinically known as infectious mononucleosis, it is extremely difficult to distinguish from GAS infection. Exudative pharyngitis is prominent. Distinctive features include retrocervical or generalized adenopathy and hepatosplenomegaly. Atypical lymphocytes can be seen on peripheral blood smear. Viral cultures from washings are about 20% sensitive in adults.
    • CMV: Presentation of CMV is similar to the presentation of infectious mononucleosis. Patients tend to be older, are sexually active, and have higher fever and more malaise. Pharyngitis may not be a prominent complaint.
    • HIV-1: This is associated with pharyngeal edema and erythema, common aphthous ulcers, and a rarity of exudates. Fever, myalgia, and lymphadenopathy also are found.
  • Other causes of pharyngitis
    • Oral thrush is due to candidal species, usually in patients who are immunocompromised. It may be common in young children and presents with whitish plaques in the oropharynx.
    • Other causes include dry air, allergy/postnasal drip, chemical injury, gastroesophageal reflux disease (GERD), smoking, neoplasia, and endotracheal intubation.

More on Pharyngitis

Overview: Pharyngitis
Differential Diagnoses & Workup: Pharyngitis
Treatment & Medication: Pharyngitis
Follow-up: Pharyngitis
Multimedia: Pharyngitis


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Further Reading

Contributor Information and Disclosures


John R Acerra, MD, Assistant Professor, Department of Emergency Medicine, Albert Einstein College of Medicine; Associate Director, International Emergency Medicine Fellowship, North Shore - LIJ Health System
John R Acerra, MD is a member of the following medical societies: American College of Emergency Physicians, Emergency Medicine Residents Association, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Medical Editor

Jerry Balentine, DO, Professor of Emergency Medicine, New York College of Osteopathic Medicine; Executive Vice President, Chief Medical Officer, Attending Physician in Department of Emergency Medicine, St. Barnabas Hospital
Jerry Balentine, DO is a member of the following medical societies: American College of Emergency Physicians, American College of Osteopathic Emergency Physicians, American College of Physician Executives, American Osteopathic Association, and New York Academy of Medicine
Disclosure: Nothing to disclose.

Pharmacy Editor

Francisco Talavera, PharmD, PhD, Senior Pharmacy Editor, eMedicine
Disclosure: eMedicine Salary Employment

Managing Editor

Mark W Fourre, MD, Program Director, Department of Emergency Medicine, Maine Medical Center; Associate Clinical Professor, Department of Surgery, University of Vermont School of Medicine
Disclosure: Nothing to disclose.

CME Editor

John D Halamka, MD, MS, Associate Professor of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center; Chief Information Officer, CareGroup Healthcare System and Harvard Medical School; Attending Physician, Division of Emergency Medicine, Beth Israel Deaconess Medical Center
John D Halamka, MD, MS is a member of the following medical societies: American College of Emergency Physicians, American Medical Informatics Association, Phi Beta Kappa, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.

Chief Editor

Pamela L Dyne, MD, Professor of Clinical Medicine/Emergency Medicine, David Geffen School of Medicine at UCLA; Attending Physician, Department of Emergency Medicine, Olive View-UCLA Medical Center
Pamela L Dyne, MD is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, and Society for Academic Emergency Medicine
Disclosure: Nothing to disclose.


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