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

Pharyngitis

Author: John R Acerra, MD, Resident Physician, Department of Emergency Medicine, Allegheny General Hospital
Coauthor(s): Andrew A Aronson, MD, Assistant Professor of Emergency Medicine, Drexel University School of Medicine; Consulting Staff, Department of Emergency Medicine, Allegheny General Hospital
Contributor Information and Disclosures

Updated: Nov 5, 2007

Introduction

Background

Pharyngitis is defined as an infection or irritation of the pharynx and/or tonsils. The etiology is usually infectious, with 40-60% of cases being of viral origin and 5-40% of cases being of bacterial origin. Other causes include allergy, trauma, toxins, and neoplasia.

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 (GABHS) infections. GABHS infections can have serious sequelae and represent approximately 15% of all ED pharyngitis visits.

Pathophysiology

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

Streptococcal infections are characterized by local invasion and release of extracellular toxins and proteases. In addition, M protein fragments of certain serotypes of GABHS 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.

Frequency

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 GABHS infection (Streptococcus pyogenes), and the most common viruses are rhinovirus and adenovirus. GABHS is most prevalent in late fall through early spring.

International

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

Mortality/Morbidity

• One in 400 cases of untreated GABHS infections can be expected to result in acute rheumatic fever. This rate is higher in less developed countries and might actually be lower in the Western world.
• 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. For the ED physician, airway obstruction is a concern.

Age

Pharyngitis occurs with much greater frequency in the pediatric population. GABHS is also more common in school-aged children. GABHS causes less than 15% of all adult cases of pharyngitis and about 15-30% of pediatric cases. 

• The peak incidence of bacterial and viral pharyngitis occurs in the school-aged child aged 4-7 years.
• Pharyngitis, especially GABHS infection, is rare in children younger than 3 years.
• Mycoplasma pneumoniae, Chlamydia pneumoniae, and Arcanobacterium haemolyticus peak as causative agents in people in the teen years through the young adulthood years.

Clinical

History

A clinical diagnosis of GABHS infection results in an overestimation of incidence by as much as 80%. Many bacterial and viral cases of pharyngitis can be indistinguishable on clinical grounds. However, the classic presentations are described below.

• GABHS infection is most common in children aged 4-7 year.
• Sudden onset is consistent with a GABHS 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 GABHS or rheumatic fever.
• Headache is consistent with GABHS or Mycoplasma infection.
• Cough is not usually associated with GABHS infection.
• Vomiting is associated with GABHS 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.

Physical

• 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.
  • Temperature can be as high as 106°F with coxsackievirus A, coxsackievirus B, herpes simplex, GABHS infection, human immunodeficiency virus 1 (HIV-1), infectious mononucleosis, and cytomegalovirus (CMV).
• 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 GABHS 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, while 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 GABHS infection (see Scarlet Fever).
  • Maculopapular rashes are seen with various viral infections and with infectious mononucleosis empirically treated with penicillin.

Causes

• Bacterial pharyngitis
  • Group A beta-hemolytic streptococci (15% of all pharyngitis)
    • 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.
    • A scarlatiniform rash also is associated with GABHS infection (scarlet fever), ie, a sandpaperlike erythematous rash over the trunk and extremities with circumoral pallor and a strawberry tongue.
  • Group C, G, and F streptococci (10%) may be indistinguishable clinically from GABHS 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. Group C streptococci have been reported to cause meningitis, endocarditis, and subdural empyemas.
  • Arcanobacterium (Corynebacterium) haemolyticus (5%) is more common in young adults and is very similar to GABHS 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 GABHS infection.
  • C pneumoniae (5%) 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.
  • Unusual bacteria that could present with pharyngitis include Borrelia species, Francisella tularensis, Yersinia species, and Corynebacterium ulcerans.
• Viral pharyngitis
  • Adenovirus (5%): 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 (5%): Vesicular lesions (herpangina), especially in young children, are the hallmark. In older patients, pharyngitis may be indistinguishable from GABHS infection.
  • Coxsackieviruses A and B (5%): 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 GABHS 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.

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