Pharyngitis overview

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Venkata Sivakrishna Kumar Pulivarthi M.B.B.S [2]

Synonyms and keywords: Sore throat; Group A streptococcal pharyngitis; Bacterial pharyngitis; Viral pharyngitis.

Overview

Pharyngitis is the inflammation of the pharynx, manifested by sore throat. It is a painful inflammation of the pharynx, and is colloquially referred to as a sore throat. Pharyngitis is a common medical problem in the outpatient medical setting, resulting in more than seven million pediatric visits each year. Most types of pharyngitis are caused by infectious etiologies. The most common cause of pharyngitis is viral infection. However, some of the more serious types of pharyngitis are attributed to bacterial etiologies, such as group A-hemolytic Streptococcus pyogenes (GAS). Complications from GAS pharyngitis include rheumatic fever, deep space abscesses, and toxic shock. Although most episodes of pharyngitis are acute in nature, a small percentage becomes recurrent or chronic. With regards to chronic pharyngitis, non-infectious etiologies, such as laryngopharyngeal reflux and periodic fever, aphthous ulcers, pharyngitis, and adenitis syndrome also need to be considered. Both medical and surgical therapies are effective in managing pharyngitis. First-line medical therapy includes antibiotic therapy. For certain indications, surgical management via adenotonsillectomy is recommended. Adenotonsillectomy has been shown to be effective in reducing disease burden and improving disease-specific and global quality of life. Several techniques for adenotonsillectomy exist, including traditional and intracapsular tonsillectomies.

Epidemiology and Demographics

Pharyngitis is one of the most common disorders in adults and children, with more than 10 million ambulatory visits per year. Viruses are the single most common cause of pharyngitis and account for 25% to 45% of all cases. Group A streptococcus presents in up to 37% of all children presenting with a sore throat to an outpatient clinic or ED and 24% of those presenting at younger than 5 years. Group A streptococcus is by far the most common bacterial cause of acute pharyngitis, accounting for approximately 15 to 30 percent of cases in children and 5 to 10 percent of cases in adults. Peak seasons for sore throat include late winter and early spring.

Risk Factors

Pharyngitis is contagious, so anyone in close proximity to someone with the illness, is at risk. Social situations with prolonged close interpersonal contact are associated with a higher incidence of the disease, such as in schools, dormitories, or military barracks. Other common risk factors include History of ill contact, Over crowding, Frequent sinus infections, Smoking, Attending day care, Immunocompromised etc.

Natural History, Complications & Prognosis

Acute pharyngitis is typically described as the triad of sore throat, fever, and pharyngeal inflammation characterized by erythema and edema, although exudates, vesicles, or ulcerations may also be present. Although pharyngitis may be a primary disorder, sore throat and pharyngeal erythema may also be prominent in systemic disorders, such as the acute retroviral syndrome, or part of a more generalized upper respiratory tract infection. Most cases of acute pharyngitis are due to common viral infections and are benign, self-limited processes. The appropriate recognition of patients with more complicated infections that require diagnostic evaluations and treatment is one of the challenges of primary care medicine. An estimated 1-2% of acute pharyngitis progresses to recurrent or chronic disease.

Diagnosis

Key points in the evaluation of acute pharyngitis

• Essential to diagnosis is the identification of treatable causes (e.g. Group A streptococcus) to prevent complications.s

• Signs and symptoms of GAS pharyngitis include acute onset of sore throat with tonsillar or pharyngeal exudates, tender anterior cervical lymphadenopathy and fever.

• Signs and symptoms consistent with viral etiologies include conjunctivitis, coryza, oral ulcers, cough, and diarrhea.

• Testing for GAS pharyngitis should not be pursued in those with signs and symptoms indicative of a viral etiology.

• Rapid antigen detection tests (RADTs) alone are sufficient for the diagnosis of GAS in adults, but negative results should be backed up by throat culture in children.

• Specific techniques should be used to identify other causes where appropriate.

History and Symptoms

Pharyngitis is a very common inflammatory condition of the pharynx accompanied by a sore throat and occasionally difficulty in swallowing. Other symptoms depends on the etiology such as bacterial or viral.

Clinical features of acute pharyngitis
Group A streptococcal pharyngitis	Viral pharyngitis
Sudden onset of sore throat Age 5–15 years Fever Headache Nausea, vomiting, abdominal pain Tonsillopharyngeal inflammation Patchy tonsillopharyngeal exudates Palatal petechiae Anterior cervical adenitis (tender nodes) Winter and early spring presentation History of exposure to strep pharyngitis Scarlatiniform rash	Conjunctivitis Coryza Cough Diarrhea Hoarseness Discrete ulcerative stomatitis Viral exanthema

Laboratory Findings

There is broad overlap between the signs and symptoms of streptococcal and non-streptococcal (usually viral) pharyngitis, and the ability to identify streptococcal pharyngitis accurately on the basis of clinical grounds alone is generally poor. Therefore, except when obvious viral clinical and epidemiological features are present, a laboratory test should be performed to determine whether GAS is present in the pharynx. Even subjects with all clinical features in a particular scoring system can be confirmed to have streptococcal pharyngitis only about 35%–50% of the time, and this is particularly the case in children. Swabbing the throat and testing for GAS pharyngitis with RADT&/ culture should be performed because the clinical features alone do not reliably discriminate between GAS and viral pharyngitis except when overt viral features like rhinorrhea, cough, oral ulcers, and/or hoarseness are present.

A test negative for GAS provides reassurance that the patient likely has a viral cause of pharyngitis. A negative test result also allows the clinician to safely avoid the use of antibiotics. Because of the general increase in rates of resistance to antibiotics, antimicrobial therapy should be prescribed only for proven episodes of GAS pharyngitis.

The major goal of the evaluation of patients with sore throat or acute pharyngitis is to exclude potentially dangerous causes (e.g. Group A streptococcus), to identify any treatable causes, and to improve symptoms. Identifying group A streptococcus (GAS) is important because timely treatment with antibiotics helps prevent poststreptococcal complications such as acute rheumatic fever. The evaluation includes a thorough history, focused physical examination, and diagnostic testing in selected patients.

Centor criteria: It is important to evaluate for definitive diagnosis to exclude GAS and to avoid unnecessary lab tests and antibiotic use. Centor criteria are a widely used and accepted clinical decision tool in identifying patients for whom neither microbiologic tests nor antimicrobial therapy are necessary.The Centor score to use for children and adults with a sore throat to estimate probability of Streptococcus pyogenes infection.

Modified Centor criteria			Appropriate management according to the total score
Criteria	Points		Total score	Chance of streptococcal infection in community with usual levels of infection, %	Suggested management
Fever (temperature > 38°C)	+1		0	2-3	No culture or antibiotic is required
Absence of cough	+1		1	4-6
Swollen and tender anterior cervical nodes	+1		2	10-12	Culture all and treat only if culture result is positive
Tonsillar swelling or exudates	+1		3	27-28
Age 3–14 yr	+1		4	38–63	Culture all and treat with penicillin on clinical grounds
Age 15–44 yr	0
Age ≥ 45 yr	-1

Special Considerations in the Diagnosis of Acute Pharyngitis in Adults

GAS causes only 5%–15% of cases of acute pharyngitis in adults. The risk of acute pharyngitis due to GAS among adults is higher for parents of school-age children and for those whose occupation brings them into close association with children. However, the risk of a first attack of ARF is extremely low in adults, even with an undiagnosed and untreated episode of streptococcal pharyngitis. Because of these epidemiological distinctions, the use of a clinical algorithm without microbiological confirmation has been suggested as an acceptable alternative basis for diagnosis of infection in adults. However, use of this diagnostic strategy would result in treatment of an unacceptably large number of adults with non-streptococcal pharyngitis, that is an undesirable result in this age group, which has a low prevalence of GAS pharyngitis and a very low risk of rheumatic fever or rheumatic carditis. However, because of the above noted features of acute pharyngitis in adults, exclusion of the diagnosis on the basis of negative RADT results without confirmation by negative culture results is an acceptable alternative to diagnosis on the basis of throat culture results.

Special Considerations in the Diagnosis of Acute Pharyngitis in Children <3 Years

The prevalence of GAS pharyngitis is significantly lower for children <3 years of age, ranging from 10% to 14%, and if a corresponding rise in ASO is required, the prevalence can be as low as 0%– 6%. Thus, diagnostic testing for GAS pharyngitis is not routinely indicated in children <3 years of age. However, if a child is <3 years of age and there is household contact with a school-aged sibling with documented streptococcal pharyngitis, then it is reasonable to consider testing the child if the child is symptomatic. Therefore, if a child is in day care or another setting with a high rate of cases of GAS infections, then it is reasonable to test symptomatic children and treat them if they are found to be positive for GAS.

Evaluation of acute pharyngitis

Treatment

As is evident from potential etiologic agents of pharyngitis, group A streptococcus is the only commonly occurring form of acute pharyngitis for which antibiotic therapy is definitely indicated. Therefore, for a patient with acute pharyngitis, the clinical decision that usually needs to be made is whether or not the pharyngitis is attributable to GAS.

Medical Therapy

Patients with acute GAS pharyngitis should be treated with an appropriate antibiotic at an appropriate dose for a duration likely to eradicate the organism from the pharynx (usually 10 days). Based on their narrow spectrum of activity, infrequency of adverse reactions, and modest cost, penicillin or amoxicillin is the recommended drug of choice for those non-allergic to these agents. Treatment of GAS pharyngitis in penicillin-allergic individuals should include a first generation cephalosporin (for those not anaphylactically sensitive) for 10 days, clindamycin or clarithromycin for 10 days, or azithromycin for 5 days. Adjunctive therapy with Nonsteroidal Anti-inflammatory Drugs (NSAIDs), Acetaminophen, Aspirin, or Corticosteroids may be useful in the management of GAS pharyngitis.

Prevention

Accurate diagnosis of streptococcal pharyngitis followed by appropriate antimicrobial therapy is important for the prevention of acute rheumatic fever and for the prevention of suppurative complications such as Peritonsillar abscess, cervical lymphadenitis, mastoiditis.

References

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