Acute Pharyngitis

Viruses

In North America and most industrialized countries, GAS is the most important bacterial cause of acute pharyngitis, but viruses predominate as acute infectious causes of pharyngitis. Viral upper respiratory tract infections are typically spread by contact with oral or respiratory secretions and occur most commonly in fall, winter, and spring—that is, the respiratory season. Important viruses that cause pharyngitis include influenza, parainfluenza, adenoviruses, coronaviruses, enteroviruses, rhinoviruses, respiratory syncytial virus (RSV), cytomegalovirus, Epstein-Barr virus (EBV), herpes simplex virus (HSV), and human metapneumovirus (HMPV) ( Table 409.1 ). Most viral pharyngitis, except mononucleosis, is mild. Common nonspecific symptoms such as rhinorrhea and cough develop gradually before they become prominent. However, specific findings are sometimes helpful in identifying the infectious viral agent ( Table 409.2 ).

Gingivostomatitis and ulcerating vesicles throughout the anterior pharynx and on the lips and perioral skin are seen in primary oral HSV infection. High fever and difficulty taking oral fluids are common. This infection can last for 14 days.

Discrete papulovesicular lesions or ulcerations in the posterior oropharynx, severe throat pain, and fever are characteristic of herpangina , caused by various enteroviruses. In hand-foot-mouth disease , there are vesicles or ulcers throughout the oropharynx, vesicles on the palms and soles, and sometimes on the trunk and extremities. Coxsackie A16 is the most common agent, but Enterovirus 71 and Coxsackie A6 can also cause this syndrome. Enteroviral infections are most common in the summer.

Various adenoviruses cause pharyngitis. When there is concurrent conjunctivitis , the syndrome is called pharyngoconjunctival fever . The pharyngitis tends to resolve within 7 days but conjunctivitis may persist for up to 14 days. Pharyngoconjunctival fever can be epidemic or sporadic; outbreaks have been associated with exposure in swimming pools.

Intense, diffuse pharyngeal erythema and Koplik spots, the pathognomonic enanthem, occur in advance of the characteristic rash of measles. Splenomegaly, lymphadenopathy, or hepatomegaly may be the clue to EBV infectious mononucleosis in an adolescent with exudative tonsillitis. Primary infection with HIV can manifest as the acute retroviral syndrome , with non-exudative pharyngitis, fever, arthralgia, myalgia, adenopathy, and often a maculopapular rash.

Bacteria Other Than Group A Streptococcus

In addition to GAS, bacteria that cause pharyngitis include group C and group G streptococcus, Arcanobacterium haemolyticum , Francisella tularensis , Neisseria gonorrhoeae , Mycoplasma pneumoniae , Chlamydophila (formerly Chlamydia ) pneumoniae , Chlamydia trachomatis , Fusobacterium necrophorum , and Corynebacterium diphtheriae . Haemophilus influenzae and Streptococcus pneumoniae may be cultured from the throats of children with pharyngitis, but their role in causing pharyngitis has not been established.

Group C and Group G streptococcus and A. haemolyticum pharyngitis have been diagnosed most commonly in adolescents and adults. They resemble group A β-hemolytic streptococcus (GAS) pharyngitis. A scarlet fever–like rash may be present with A. haemolyticum infections.

F. necrophorum has been suggested to be a fairly common cause of pharyngitis in older adolescents and adults (15-30 yr old). Prevalence in studies has varied from 10% to 48% of patients with non-GABHS pharyngitis, but large surveillance studies have not been performed. F. necrophorum was detected by PCR in 20.5% of patients with pharyngitis in a study based in a university health clinic and in 9.4% of an asymptomatic convenience sample; some patients had more than 1 bacterial species detected by PCR. Pharyngitis patients with F. necrophorum had signs and symptoms similar to GAS pharyngitis: about one third had fever, one third had tonsillar exudates, two thirds had anterior cervical adenopathy, and most did not have cough. This organism is difficult to culture from the throat, and diagnostic testing with PCR is not generally available. F. necrophorum pharyngitis is associated with the development of Lemierre syndrome (see Chapter 410 ), internal jugular vein septic thrombophlebitis. Approximately 80% of cases of Lemierre syndrome are caused by this bacterium. Patients present initially with fever, sore throat, exudative pharyngitis, and/or peritonsillar abscess. The symptoms may persist, neck pain and swelling develop, and the patient appears toxic. Septic shock may ensue, along with metastatic complications from septic emboli that can involve the lungs, bones and joints, central nervous system, abdominal organs, and soft tissues. The case fatality rate is 4–9%.

Gonococcal pharyngeal infections are usually asymptomatic but can cause acute ulcerative or exudative pharyngitis with fever and cervical lymphadenitis. Young children with proven gonococcal disease should be evaluated for sexual abuse.

Diphtheria is extremely rare in most developed countries due to extensive immunization with diphtheria toxoid. However, it remains endemic in many areas of the world, including the former Soviet bloc countries, Africa, Asia, the Middle East, and Latin America. It can be considered in patients with recent travel to or from these areas and in unimmunized patients. Key physical findings are bull neck (extreme neck swelling) and a gray pharyngeal pseudomembrane that can cause respiratory obstruction.

Ingestion of water, milk, or undercooked meat contaminated by F. tularensis can lead to oropharyngeal tularemia. Severe throat pain, tonsillitis, cervical adenitis, oral ulcerations, and a pseudomembrane (as in diphtheria) may be present. M. pneumoniae and C. pneumonia e cause pharyngitis, but other upper and lower respiratory infections are more important and more readily recognized. Development of a severe or persistent cough subsequent to pharyngitis may be the clue to infection with 1 of these organisms.