Pharyngitis 

Updated: Apr 11, 2018
Author: John R Acerra, MD; Chief Editor: Jeter (Jay) Pritchard Taylor, III, MD 

Overview

Practice Essentials

Pharyngitis is defined as an infection or irritation of the pharynx or tonsils (see the image below). The etiology is usually infectious, with most cases being of viral origin and most bacterial cases attributable to group A streptococci (GAS). Other causes include allergy, trauma, toxins, and neoplasia.

Posterior pharynx with petechiae and exudates in a 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.

Signs and symptoms

It is difficult to distinguish viral and bacterial causes of pharyngitis on the basis of history and physical examination alone. Nevertheless, the following factors may help rule out or diagnose GAS pharyngitis:

  • GAS infection is most common in children aged 4-7 years

  • Sudden onset is consistent with GAS pharyngitis; pharyngitis after several days of coughing or rhinorrhea is more consistent with a viral etiology

  • Contact with others who have GAS or rheumatic fever with symptoms consistent with GAS raises the likelihood of GAS pharyngitis

  • Headache is consistent with GAS infection

  • Cough is not usually associated with GAS infection

  • Vomiting is associated with GAS infection, though not exclusively so

  • Recent orogenital contact suggests possible gonococcal pharyngitis

  • A history of rheumatic fever is important

Centor criteria for GAS pharyngitis include the following:

  • Fever (1 point)

  • Anterior cervical lymphadenopathy (1 point)

  • Tonsillar exudate (1 point)

  • Absence of cough (1 point)

A score of 0-1 makes GAS infection unlikely; a score of 4 makes it likely. In adults, the positive predictive value of these criteria is around 40% if 3 criteria are met and about 50% if 4 criteria are met.

Physical examination includes the following:

  • Assessment of airway patency

  • Temperature

  • Hydration status

  • Head, ears, eyes, nose, and throat – Conjunctivitis, scleral icterus, rhinorrhea, tonsillopharyngeal/palatal petechiae, tonsillopharyngeal exudate, oropharyngeal vesicular lesions

  • Lymphadenopathy (cervical or generalized)

  • Cardiovascular evaluation

  • Pulmonary assessment

  • Abdominal examination

  • Skin examination

See Clinical Presentation for more detail.

Diagnosis

Laboratory studies that may be helpful include the following:

  • Group A beta-hemolytic streptococcal rapid antigen detection test (preferred diagnostic method in emergency settings)

  • Throat culture (criterion standard for diagnosis of GAS infection [90-99% sensitive])

  • Mono spot (up to 95% sensitive in children; less than 60% sensitive in infants)

  • Peripheral smear

  • Gonococcal culture if indicated by the history

Imaging studies generally are not indicated for uncomplicated viral or streptococcal pharyngitis. However, the following may be considered:

  • Lateral neck film in patients with suspected epiglottitis or airway compromise

  • Soft-tissue neck CT if concern for abscess or deep-space infection exists

A throat swab may also be done.

See Workup for more detail.

Management

Prehospital care usually is not necessary for uncomplicated pharyngitis unless airway compromise is an issue. Intubation should not be attempted unless the patient stops breathing spontaneously.

Emergency measures may include the following:

  • Assess and secure the airway, if necessary

  • Assess the patient for signs of toxicity, epiglottitis, or oropharyngeal abscess

  • Evaluate hydration status, and rehydrate as necessary

  • Assess for GAS infection if clinically suspected

Most cases, whether viral or bacterial, are relatively benign and self-limited. Management of GAS infection, when indicated, includes the following:

  • Do not treat patients without a positive culture or positive rapid antigen detection test result

  • Perform a rapid antigen detection test if GAS is clinically suspected on the basis of the history and physical examination; if test results are positive, begin antibiotic therapy

  • Patients who are positive for all 4 Centor criteria can often be treated with antibiotics without antigen testing or cultures

  • Household contacts of patients with GAS infection or scarlet fever should be treated for a full 10 days of antibiotics without testing only if they have symptoms consistent with GAS; asymptomatic contacts should not be treated

  • If the diagnosis is in doubt or the above criteria are not met, initiation of antibiotic therapy should await rapid antigen test or culture results

See Treatment and Medication for more detail.

Background

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]

The most significant bacterial agent causing pharyngitis in both adults and children is GAS infection (Streptococcus pyogenes); this is shown in the image below.


Streptococcus pyogenes at 100X magnification. Streptococcus pyogenes at 100X magnification.

Physical findings of GAS are shown in the image below.

Posterior pharynx with petechiae and exudates in a 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.

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]

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. Airway obstruction is also of utmost importance for the ED physician treating pharyngitis.

Pathophysiology

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. The prevalence rates of these serotypes of GAS have been becoming rarer over the past several years. Acute glomerulonephritis may result from antibody-antigen complex deposition in glomeruli.[3]

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 GAS infection (Streptococcus pyogenes), and the most common viruses are rhinovirus and adenovirus. GAS is most prevalent in late fall through early spring.[1]

International

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]

A study by Banigo et al reported that the reduction in the number of tonsillectomies performed in England (28,309 in 1990/1991 vs 6327 in 2013/2014) correlates with an increase in the number of hospital admissions in that country for acute tonsillitis and pharyngitis and with an increase in invasive group A beta-hemolytic streptococcal (GABHS) infections. Indeed, over the course of the 1990/1991 to 2013/2014 period, the number of invasive GABHS infections rose more than two-fold in children aged 14 years or younger.[50]

Mortality/Morbidity

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] The US Centers for Disease Control and Prevention (CDC) stopped tracking the incidence of rheumatic heart disease in the United States in 1994, when the incidence dropped to less than 1 case per million US general population.[6]

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.

Age

Pharyngitis occurs with much greater frequency in the pediatric population. Approximately 15-30% of sore throats in children are caused by group A beta-hemolytic streptococcal (GABHS) infections, compared with 5-15% of adults.[1, 7]

The peak incidence of bacterial and viral pharyngitis occurs in the school-aged child aged 4-7 years, with GABHS occurring primarily in patients aged 5-15 years. Pharyngitis, especially GAS infection, is rare in children younger than 3 years.

In a study of 3098 pediatric patients with pharyngitis, Nishiyama et al found the prevalence of GAS pharyngitis to be 1.2% in patients below age 1 year and 3.9% in patients aged 1 year.[49]

 

Presentation

History

Viral and bacterial causes of pharyngitis are similar, and the differentiation of the etiology is difficult based on history and physical examination alone. Signs and symptoms alone cannot be used to rule out or diagnose GAS pharyngitis.[8] 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 presenting with symptoms consistent with GAS are more likely to have GAS pharyngitis.

  • 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.[9] 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.[10] 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.[11] These criteria along with other clinical features should be used to guide treatment for pharyngitis in adults. A modified version of the Centor score, in which age is also taken account (and which is also called the McIsaac score), can be used in diagnosis as well.[12, 13]

Physical

See the list below:

  • 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).[14]

    • Maculopapular rashes are seen with various viral infections and with infectious mononucleosis empirically treated with penicillin.

Causes

See the list below:

  • Bacterial pharyngitis

    • Group A beta-hemolytic streptococci (GABHS): 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.[14]

    • 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 pharyngitis[3]

    • 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.

    • A rare but life-threatening cause of pharyngitis in young adults is Lemierre's syndrome. This condition is usually caused by the anaerobic bacterium, Fusobacterium necrophorum, and is characterized by a oropharyngeal infection with evidence of septic thrombophlebitis. The incidence is approximately one in a million, but it should be considered when a critically ill patient presents with pharyngitis.[15]

 

DDx

 

Workup

Laboratory Studies

 

GABHS rapid antigen detection test

This is the preferred method for diagnosing GAS infection in the emergency department because of difficulties with culture follow-up. (See the image below.)

Rapid antigen detection test for group A beta-hemo Rapid antigen detection test for group A beta-hemolytic streptococci.

Only patients with a high clinical likelihood of GAS pharyngitis should be tested. Patients with a Centor score of 0-1 should be treated symptomatically without testing.[16]  (On the other hand, in a multicenter, prospective, cross-sectional study, Cohen et al suggested that all children with pharyngitis undergo the rapid antigen detection test for GAS, stating that assessment of signs and symptoms is an inefficient means of determining in which patients the test should be used.[17] )

Antigens are specific, but sensitivities vary. The sensitivity of the GABHS rapid antigen detection test is 70-90%, and the specificity is 90-100%, depending on the manufacturer.[18, 19, 20, 21] Children with a negative antigen test should have a follow-up culture unless the antigen being used in the office has been shown to be as sensitive as a culture.[14]

The use of a GABHS rapid antigen detection test can decrease the use of unnecessary antibiotics in pediatric patients when used properly.[22]

Adults do not need follow-up culture after a negative antigen test because of the low incidence of GAS in this population.[10]

Throat culture

This is the criterion standard for diagnosis of GAS infection (90-99% sensitive).[52] Although less expensive than the rapid antigen detection test, it is not be the best test to use in the emergency department because of difficulty with follow-up. The guidelines that recommend cultures for GAS screening are aimed at office-based practices and not the emergency department.

Patients can be treated up to 9 days after onset of symptoms to prevent acute rheumatic fever, so immediate antibiotic therapy is not crucial if patients can be easily contacted for follow-up should a culture become positive.[1]

Other

Additional tests include the following:

  • Mono spot is up to 95% sensitive in children (less than 60% sensitivity in infants)
  • Peripheral smear may show atypical lymphocytes in infectious mononucleosis [2]
  • Perform gonococcal culture as indicated by history
  • A complete blood count (CBC), erythrocyte sedimentation rate (ESR), and C-reactive protein have a low predictive value and usually are not indicated [23]

Imaging Studies

See the list below:

  • Imaging studies generally are not indicated for uncomplicated viral or streptococcal pharyngitis.

  • Lateral neck film should be taken in patients with suspected epiglottitis or airway compromise.

  • Soft tissue neck CT can be used if concern for abscess or deep-space infection exists; however, peritonsillar abscess is almost always a clinical diagnosis. Imaging is rarely needed for diagnosis.

Procedures

See the list below:

  • The procedure for a throat swab is to vigorously rub a dry swab over the posterior pharynx and both tonsils, obtaining a sample of exudate. If any exudate is obtained, then transport it dry (not in a liquid medium).

 

Treatment

Prehospital Care

See the list below:

  • Prehospital care usually is not necessary for uncomplicated pharyngitis unless airway compromise is an issue.

  • Intubation should not be attempted unless the patient stops breathing spontaneously.

Emergency Department Care

See the list below:

  • Assess and secure the airway, if necessary.

  • Assess the patient for signs of toxicity, epiglottitis, or oropharyngeal abscess.[24]

  • Evaluate the hydration status because severe pharyngitis limits oral intake. Appropriate measures to rehydrate should be initiated, including intravenous hydration.

  • Assess for GAS infection if clinically suspected. A suggested algorithm as is follows.

    • In general, patients should not be treated without a positive culture or positive rapid antigen detection test result because of increasing antibiotic resistance. Guidelines from the Infectious Diseases Society of America (IDSA) and American Heart Association state that microbiologic confirmation (via a rapid antigen test or culture) is required for the diagnosis of GAS.[10, 5]

    • Perform rapid antigen detection test if GAS is clinically suspected based on history and physical examination. If positive, begin antibiotic therapy. Testing does not usually need to be performed on patients with acute pharyngitis whose clinical and epidemiologic features do not suggest GAS as the etiology (Centor score 0-1).

    • Patients who are positive for all 4 Centor criteria can often be treated with antibiotics without antigen testing or cultures.

    • Household contacts of patients with GAS infection or scarlet fever should be treated for a full 10 days of antibiotics without testing only if they have symptoms consistent with GAS.[5] Asymptomatic contacts should not be treated.

    • If clinically doubtful or the above criteria are not met, it is best to await rapid antigen or culture results to initiate antibiotic therapy.

A study by Cohen et al suggested that rules-based selective testing strategies for children with pharyngitis do not have a sufficient combination of sensitivity and specificity to determine which patients should be tested for group A streptococcal infection. Using an external validation cohort of 676 children, the investigators determined that none of the clinical prediction rules used in the study reached the investigators’ diagnostic accuracy target; specifically, a sensitivity and specificity of greater than 85%.[25]

Consultations

With a few exceptions, uncomplicated cases of pharyngitis should not require a consultation. Infectious disease specialists should be consulted in the case of unusual presentation or in the case of a patient who is immunocompromised.

 

Guidelines

Guidelines Summary

The Choosing Wisely medical initiative picked the top guidelines from the Italian Panel of the National Guidelines for the Management of Acute Pharyngitis in Children. The chosen recommendations are as follows[26] :

  • Blood exams should not be performed
  • Antibiotics should not be administrated unless microbiologic confirmation of streptococcal infection has been carried out
  • If a throat culture is performed, susceptibility tests on isolates should not be executed
  • The antibiotic course should not be shortened
  • Because penicillin V is not available in Italy, amoxicillin (50 mg/kg/d in 2-3 doses orally) for 10 days is the first choice treatment
  • Steroids should not be administered, to avoid masking a possible underlying severe condition
 

Medication

Medication Summary

GAS pharyngitis is usually a self-limited disease, and most signs and symptoms resolve spontaneously in 3-4 days. If administered early, antibiotics can shorten the duration of the illness by up to 1 day, but the main reason they are given is for prevention of acute rheumatic fever.[27] This rationale is being questioned by many as the incidence of acute rheumatic fever in the United States is extremely low. In addition, pain medications such as NSAIDs or acetaminophen and steroids can alleviate the symptoms associated with GAS pharyngitis.[28] Antibiotics do not prevent acute glomerulonephritis. Steroids may be used for airway compromise and symptomatic relief.[29] Antifungals and antivirals are used in certain rare cases with specialist consultation.

A randomized, double-blind study by Shephard et al suggested that lozenges containing flurbiprofen 8.75 mg can alleviate moderate to severe pharyngitis symptoms for 3-4 hours, whether or not the patient is suffering from a group A or C streptococcal infection.[30]

A study by Müller et al indicated that a mouth and throat spray containing the osmolyte ectoine is effective against acute pharyngitis and/or laryngitis, demonstrating good to very good tolerability and reducing cervical lymph node swelling to a significantly greater degree than saline lozenges. The prospective, controlled, nonrandomized trial included 95 patients.[31]

A study by Fleming-Dutra et al found that, based on the 2010-2011 National Ambulatory Medical Care Survey and National Hospital Ambulatory Medical Care Survey, pharyngitis was responsible for 43 ambulatory antibiotic prescriptions per 1000 population in the United States, the third highest rate of such prescriptions for a single diagnosis (after sinusitis and suppurative otitis media).[32, 33, 34]

Antibiotics

Class Summary

Empiric antimicrobial therapy must be comprehensive and should cover all likely pathogens in the context of the clinical setting. Antibiotics are indicated for clinically suspected and culture or antigen-verified GAS infection. They are effective in preventing rheumatic fever if given within 9 days of the onset of pharyngitis.

Of note, some experts question the use of antibiotics for the treatment of GAS infection in the Western world because of the low prevalence of rheumatic fever. Some European guidelines for the treatment of pharyngitis only recommend antibiotics for patients with culture-positive GAS pharyngitis who are high-risk for acute rheumatic fever or very ill.[35] One study suggested that observation alone was most cost-effective strategy for GAS pharyngitis in children, and this strategy also had lower morbidity and mortality than antibiotic treatment groups.[36] For now, most experts and guidelines in the United States still recommend treatment with antibiotics. It should be noted, however, that the risk of a serious antibiotic adverse effects is higher than the risk of developing acute rheumatic fever as a consequence of GAS pharyngitis in the United States.

Some support the use of cephalosporins instead of penicillin as first-line therapy for GAS.[37, 38] They cite literature that shows greater eradication of the bacteria in the pharynx after treatment with a cephalosporin. No evidence suggests that this is clinically significant, and clinical guidelines still advocate that penicillin is still the drug of choice for GAS in the United States. There has never been a clinical isolate of GAS documented to be resistant to penicillin anywhere in the world.[10] In cases of clinical treatment failure of GAS pharyngitis after penicillin therapy, a cephalosporin or broader-spectrum penicillin (ampicillin-sulbactam) should be considered, but these instances are rare.[24] Cephalosporins should be considered first-line therapy if the patient has a history of recent antibiotic usage, recurrent pharyngitis infection, or if a high failure rate of penicillin is documented in the community.[39]

Macrolide resistance of GAS varies widely from year to year and among different parts of the world from 5% to 97%. Patients should only be treated with a macrolide if a penicillin or cephalosporin type drug is not an option. If a macrolide is used to treat GAS, patients should be followed closely for treatment failure, as very rare case reports describe acute rheumatic fever after GAS treatment with macrolides.[40]

Some controversy exists regarding the treatment of carriers of GAS. These are patients who have a positive rapid antigen or culture without symptoms of pharyngitis. It is believed that this carrier state does not lead to acute rheumatic fever or other complications of GAS pharyngitis. Most carriers should not be treated; however, treatment should be considered in carriers with the following characteristics:

- Recurrent pharyngitis without cough or congestion

- Acute rheumatic fever (ARF) or poststreptococcal glomerulonephritis outbreaks

- GAS pharyngitis in closed community

- Family history of ARF

- Multiple documented GAS pharyngitis episodes within a family over several weeks despite therapy

If carriers are treated, clindamycin for 10 days or IM penicillin plus 4 days of rifampin are recommended treatment options.[41]

While some literature exists to support the use of a shorter course of antibiotic therapy for GAS pharyngitis, most international guidelines still recommend a 10-day course for most antibiotics.[42]

Penicillin G benzathine (Bicillin LA)

Inhibits biosynthesis of cell wall mucopeptide. Bactericidal against sensitive organisms when adequate concentrations reached, and most effective during stage of active multiplication. Inadequate concentrations may produce only bacteriostatic effects. Still is drug of choice in GAS pharyngitis because of its narrow spectrum of activity, low cost, and proven safety track record. IM penicillin is drug of choice in patients where compliance is an issue because of single dose.

Penicillin VK (Beepen-VK)

Inhibits the biosynthesis of cell wall mucopeptide. Bactericidal against sensitive organisms when adequate concentrations are reached. Most effective during stage of active multiplication. Inadequate concentrations may produce only bacteriostatic effects. Poor patient compliance due to dosing frequency and duration plagues this drug regimen. However, tid dosing is shown in some studies to be as effective as qid dosing. For recurrent streptococcal infections, a combination of penicillin VK and rifampin may be used. Rifampicin, 20 mg/kg/d for 4 d, is added to the standard 10-d treatment with penicillin.

Amoxicillin (Amoxil, Biomox, Trimox)

Interferes with synthesis of cell wall mucopeptides during active multiplication resulting in bactericidal activity against susceptible bacteria. Associated with higher incidence of rash. No advantage over oral penicillin, but sometimes more acceptable to children because of taste. Some studies suggest that once-daily dosing of amoxicillin is adequate therapy for GABHS, but further studies are needed to validate this treatment regimen.

Cephalexin (Keflex)

First-generation cephalosporin arrests bacterial growth by inhibiting bacterial cell wall synthesis. Bactericidal activity against rapidly growing organisms. Primary activity against skin flora. Used for skin infections or prophylaxis in minor procedures. Choice for patients who are sensitive for penicillin.

Azithromycin (Zithromax)

This antibiotic has a higher cost but has a slightly higher effectiveness than erythromycin. Shorter course and one-a-day dosing make this a good alternative for patients who are allergic to penicillin.

Erythromycin (EES, Erythrocin, Ery-Tab)

Interferes with synthesis of cell wall mucopeptides during active multiplication resulting in bactericidal activity against susceptible bacteria (eg, M pneumoniae, C pneumoniae, A haemolyticus), which generally are not sensitive to penicillin. Indicated for patients allergic to penicillin. GABHS resistance is generally thought to be less than 5% in the United States, but more recent studies show resistance rates of up to 30%.

Clindamycin (Cleocin)

Semisynthetic antibiotic produced by 7(S)-chloro-substitution of 7(R)-hydroxyl group of parent compound lincomycin. Inhibits bacterial growth, possibly by blocking dissociation of peptidyl tRNA from ribosomes, causing RNA-dependent protein synthesis to arrest. Widely distributes in the body without penetration of CNS. Protein bound and excreted by the liver and kidneys.

Used for treatment of serious skin and soft tissue staphylococcal infections. Also effective against aerobic and anaerobic streptococci (except enterococci). More effective than penicillin in eliminating chronic streptococcal carriage. Recommended for treatment of symptomatic people with multiple, recurrent episodes of GABHS pharyngitis confirmed by rapid antigen testing or culture.

Ceftriaxone (Rocephin)

Third-generation cephalosporin with broad-spectrum gram-negative activity; lower efficacy against gram-positive organisms; higher efficacy against resistant organisms. Arrests bacterial growth by binding to one or more penicillin-binding proteins. Indicated for cases of gonococcal pharyngitis. Dosing is different for neonatal gonorrhea.

Corticosteroids

Class Summary

Steroids have been shown to improve clinical symptoms in patients with pharyngitis, particularly in patients with severe or exudative pharyngitis.[43] Steroids are also used in cases of airway obstruction. They have been shown in several studies to reduce clinical symptoms and to shorten the clinical course.[44, 45] They should be used selectively for patients with significant swelling or odynophagia.[29, 45]

Dexamethasone (Decadron)

Decreases inflammation by suppressing migration of polymorphonuclear leukocytes and reducing capillary permeability. For pharyngitis, steroids must be administered in conjunction with antibiotics. Provides symptomatic relief for severe pharyngitis. A one-time IM dose is convenient and avoids compliance issues. Betamethasone is an alternative to dexamethasone.

Prednisone (Deltasone, Orasone, Sterapred)

May decrease inflammation by reversing increased capillary permeability and suppressing PMN activity. Inactive and must be metabolized to the active metabolite prednisolone. The conversion may be impaired in patients with liver disease.

Antifungals

Class Summary

These agents are indicated for cases of pharyngitis associated with oral thrush.

Nystatin (Mycostatin)

Fungicidal and fungistatic antibiotic obtained from Streptomyces noursei. Effective against various yeasts and yeastlike fungi. Changes permeability of fungal cell membrane after binding to cell membrane sterols, causing cellular contents to leak. Treatment should continue until 48 h after disappearance of symptoms.

Fluconazole (Diflucan)

Synthetic oral antifungal (broad-spectrum bistriazole) that selectively inhibits fungal CYP-450 and sterol C-14 alpha-demethylation.

 

Follow-up

Further Outpatient Care

See the list below:

  • Follow-up for GAS pharyngitis

    • A standardized protocol needs to be established at each institution or ED to ensure follow-up for patients with pending throat cultures. This is particularly challenging with unreliable patients and with a shift-dependent ED practice.

    • Whether or not they are given antibiotics, patients diagnosed with pharyngitis should follow up if symptoms do not improve within 72 hours.

    • Routine posttreatment throat cultures are unnecessary and may remain positive for several weeks.[1]

    • A follow-up culture should be taken if history or evidence of rheumatic fever or if symptoms are consistent with a relapse.[39]

  • Patients with infectious mononucleosis should be instructed to follow up with their physician in 1 week. These patients should also be advised to avoid contact sports.[14]

  • Viral pharyngitis generally requires no specific follow-up unless immunosuppression is suspected or symptoms worsen.

  • Patients with suspected malignancy should be referred to an otolaryngologist for follow-up.

Further Inpatient Care

See the list below:

  • Inpatient care usually is not indicated except in cases such as epiglottitis, severe dehydration, deep-space infection, other airway compromise, or diphtheria.

Transfer

See the list below:

  • Transfer usually is not necessary for simple acute pharyngitis.

  • The airway should be evaluated and endotracheal intubation should be performed prior to transfer if a high probability of compromise exists during transfer.

Deterrence/Prevention

See the list below:

  • Throat cultures should be obtained on close contacts of patients with a history of a nonsuppurative complication (acute rheumatic fever) of a streptococcal infection or if recurrent outbreaks of GAS pharyngitis occur.[5]

  • Diphtheria immunization is highly effective and recommended for nonimmunized patients to reduce potential morbidity and mortality of the disease.

Complications

See the list below:

  • General complications of pharyngitis (mainly seen in cases of bacterial pharyngitis) include sinusitis, otitis media, epiglottitis, mastoiditis, and pneumonia.

    • Suppurative complications of bacterial pharyngitis result from spread of infection from pharyngeal mucosa via hematogenous, lymphatic, or direct extension (more common with GAS); peritonsillar abscess; retropharyngeal abscess; or suppurative cervical lymphadenitis. It is unclear if antibiotic therapy can prevent these complications as abscess isolates are often polymicrobial. Many experts believe these are actually independent entities and not related to GAS pharyngitis.

  • In addition to the above general complications, nonsuppurative complications (3% incidence) specific to GAS infection include acute rheumatic fever (3-5 wk postinfection), poststreptococcal glomerulonephritis, and toxic shock syndrome.

  • Complications of infectious mononucleosis include splenic rupture (contact sports should be avoided for 6 wk), hepatitis, Guillain-Barré syndrome, encephalitis, hemolytic anemia, agranulocytosis, myocarditis, B-cell lymphoma, and nasopharyngeal carcinoma. Use of penicillin in cases of infectious mononucleosis results in near 100% incidence of rash.[14]

Prognosis

See the list below:

  • Most cases of pharyngitis resolve spontaneously within 10 days, but it is important for the clinician to be aware of potential complications listed above.

  • Treatment failures are frequent and are attributed mainly to poor compliance, antibiotic resistance, untreated close contacts, carrier states, and antibiotic-related or copathogenic suppression of host immunity and necessary flora.[4] Of note, GAS resistance to penicillin is NOT thought to be a reason for treatment failures with penicillin.

  • Patients should expect improvement in symptoms in penicillin-sensitive streptococcal pharyngitis within 24 hours of initiation of treatment. Contagious and often the febrile periods also are reduced to 1 day. It should be noted that pain medications and steroid use for pharyngitis are extremely effective for improving symptoms of pharyngitis.[28]

Patient Education

See the list below:

  • Patients must be instructed to complete the full course of antibiotic therapy, as improvement may occur rapidly.

  • Patients should be instructed to follow up when indicated (see Further Outpatient Care).

  • Patients with infectious mononucleosis should be instructed to avoid contact sports for a period of 6 weeks because of the possibility of splenic rupture.

  • Patients should be educated about symptomatic treatment of pharyngitis.

    • Ibuprofen or acetaminophen is recommended for analgesia.

    • Saltwater gargle, warm liquids, and rest may be helpful in relieving symptoms.

  • For patient education resources, see the Infections Center. Also see the patient education articles Sore Throat and Mononucleosis.

 

Questions & Answers

Overview

What is pharyngitis (sore throat)?

How are viral and bacterial causes of pharyngitis (sore throat) differentiated?

What are the Centor criteria for group A streptococcal (GAS) pharyngitis (strep throat)?

How is the Centor score for group A streptococcal (GAS) pharyngitis (strep throat) interpreted?

What is included in the physical exam of pharyngitis (sore throat)?

What is the role of lab studies in the diagnosis of pharyngitis (sore throat)?

What is the role of imaging studies in the diagnosis of pharyngitis (sore throat)?

How is pharyngitis (sore throat) managed?

What is included in treatment of pharyngitis (sore throat) in the emergency department (ED)?

What are the treatment options for group A streptococcal (GAS) pharyngitis (strep throat)?

What are the causes of pharyngitis (sore throat)?

What is the most common bacteria that causes pharyngitis (sore throat)?

How is pharyngitis (sore throat) characterized?

Aside from GAS (Streptococcus pyogenes), what other bacteria cause pharyngitis (sore throat)?

What are the main concerns in the emergency department (ED) regarding pharyngitis (sore throat)?

What is the pathophysiology of pharyngitis (sore throat)?

What are the characteristics of group A streptococcal (GAS) pharyngitis (strep throat)?

What is the incidence of pharyngitis (sore throat) in the US?

What is the global incidence of pharyngitis (sore throat)?

What are complications of streptococcal pharyngitis (sore throat)?

What is the mortality rate for pharyngitis (sore throat)?

How does the prevalence of pharyngitis (sore throat) vary by age?

Presentation

What are the classic presentations of pharyngitis (sore throat)?

What are the Centor criteria used to diagnose and treat group A streptococcal (GAS) pharyngitis (strep throat)?

How are the Centor criteria scored for group A streptococcal (GAS) pharyngitis (strep throat)?

What are the physical findings characteristic of pharyngitis (sore throat)?

Which organisms cause bacterial pharyngitis (sore throat)?

Which organisms cause viral pharyngitis (sore throat)?

What are less common causes of pharyngitis (sore throat)?

DDX

Which conditions should be included in the differential diagnoses of pharyngitis (sore throat)?

What are the differential diagnoses for Pharyngitis?

Workup

How is group A streptococcal (GAS) pharyngitis (strep throat) diagnosed?

What is the role of the group A beta-hemolytic streptococcal (GABHS) rapid antigen detection test in the diagnosis of pharyngitis (sore throat)?

How accurate is the group A beta-hemolytic streptococcal (GABHS) rapid antigen detection test for the diagnosis of pharyngitis (sore throat)?

What are the benefits of the group A beta-hemolytic streptococcal (GABHS) rapid antigen detection test for the diagnosis of pharyngitis (sore throat)?

What is the role of throat culture in the diagnosis of pharyngitis (sore throat)?

What lab tests may be useful in the workup of pharyngitis (sore throat)?

What is the role of imaging studies in the diagnosis of pharyngitis (sore throat)?

How is a throat swab obtained for the diagnosis of pharyngitis (sore throat)?

Treatment

What prehospital care is needed for pharyngitis (sore throat)?

What is included in emergency department (ED) care for pharyngitis (sore throat)?

What is the reliability of selective testing strategies for the diagnosis of pharyngitis (sore throat)?

When is specialist consultation needed for the management of pharyngitis (sore throat)?

Guidelines

What are the Choosing Wisely recommendations for the management of acute pharyngitis (sore throat) in children?

Medications

What is the role of osmolyte ectoine spray in the treatment of pharyngitis (sore throat)?

What is the role of medications in the treatment of pharyngitis (sore throat)?

What is the role of flurbiprofen lozenges in the treatment of pharyngitis (sore throat)?

What is the medication prescription history for pharyngitis (sore throat)?

Which medications in the drug class Antifungals are used in the treatment of Pharyngitis?

Which medications in the drug class Corticosteroids are used in the treatment of Pharyngitis?

Which medications in the drug class Antibiotics are used in the treatment of Pharyngitis?

Follow-up

What monitoring is needed following treatment of pharyngitis (sore throat) in the emergency department?

When is inpatient care indicated for pharyngitis (sore throat)?

When is transfer indicated for treatment of pharyngitis (sore throat)?

How is pharyngitis (sore throat) prevented?

What are complications of pharyngitis (sore throat)?

What is the prognosis of pharyngitis (sore throat)?

What information about pharyngitis (sore throat) should patients receive?