eMedicine Specialties > Infectious Diseases > HEENT Infections

Pharyngitis, Viral

Author: KoKo Aung, MD, MPH, FACP, Associate Professor, Department of Medicine, University of Texas Health Science Center; Adjunct Assistant Professor of Public Health, University of Texas School of Public Health
Coauthor(s): Ambrish Ojha, MD, Staff Physician, Department of Internal Medicine, Texas Tech University Health Sciences Center; Carson Lo, MD, Staff Physician, Department of Medicine, Memorial Hermann Southwest Hospital
Contributor Information and Disclosures

Updated: Jan 20, 2009

Introduction

Background

Viral pharyngitis can be caused by numerous viruses. Acute pharyngitis is an inflammatory syndrome of the pharynx and/or tonsils caused by several different groups of microorganisms. Pharyngitis can be part of a generalized upper respiratory tract infection or a specific infection localized in the pharynx.

Most cases are caused by viruses and occur as part of common colds and influenzal syndromes. For information on bacterial pharyngitis, see the eMedicine article Pharyngitis, Bacterial in the Infectious Diseases volume.

Pathophysiology

Several viruses can cause viral pharyngitis.

Rhinovirus

More than 100 different serotypes of rhinovirus cause approximately 20% of cases of pharyngitis and 30-50% of common colds. These viruses enter the body through the ciliated epithelium that lines the nose, causing edema and hyperemia of the nasal mucous membranes. This condition leads to increased secretory activity of the mucous glands; swelling of the mucous membranes of the nasal cavity, eustachian tubes, and pharynx; and narrowing of nasal passages, causing obstructive symptoms. Bradykinin and lysyl-bradykinin are generated in the nasal passages of patients with rhinovirus colds, and these mediators stimulate pain nerve endings. The virus does not invade the pharyngeal mucosa. Transmission occurs by large particle aerosols or fomites.

Adenovirus

In children, adenovirus causes uncomplicated pharyngitis (most commonly caused by adenovirus types 1-3 and 5) or pharyngoconjunctival fever. The latter is characterized by fever, sore throat, and conjunctivitis. Unlike rhinovirus infections, adenovirus directly invades the pharyngeal mucosa, as shown by the viral cytopathic effect.

Epstein-Barr virus

Epstein-Barr virus (EBV) is the causal agent of infectious mononucleosis. EBV usually spreads from adults to infants. Among young adults, EBV spreads through saliva and, rarely, through blood transfusion. In addition to edema and hyperemia of the tonsils and pharyngeal mucosa, an inflammatory exudate and nasopharyngeal lymphoid hyperplasia also develop. Pharyngitis or tonsillitis is present in about 82% of patients with infectious mononucleosis.

Herpes simplex virus

Herpes simplex virus (HSV) types 1 and 2 cause gingivitis, stomatitis, and pharyngitis. Acute herpetic pharyngitis is the most common manifestation of the first episode of HSV-1 infection. After HSV enters the mucosal surface, it initiates replication and infects either sensory or autonomic nerve endings. The neurocapsid of the virus is intra-axonally transported to the nerve cell bodies in the ganglia and contiguous nerve tissue. The virus then spreads to other mucosal surfaces through centrifugal migration of infectious virions via peripheral autonomic or sensory nerves. This mode of spread explains the high frequency of new lesions distant from the initial crop of vesicles characteristic of oral-labial HSV infection.

Influenza virus

Pharyngitis and sore throat develop in about 50% of the patients with influenza A and in a lesser proportion of patients with influenza B. Severe pharyngitis is particularly common in patients with type A. The influenza virus invades the respiratory epithelium, causing necrosis, which predisposes the patient to secondary bacterial infection. Transmission of influenza occurs by aerosolized droplets.

Parainfluenza virus

Pharyngitis caused by parainfluenza virus types 1-4 usually manifests as the common cold syndrome. Parainfluenza virus type 1 infection occurs in epidemics, mainly in late fall or winter, while parainfluenza virus type 2 infection occurs sporadically. Parainfluenza virus type 3 infection occurs either epidemically or sporadically.

Coronavirus

Pharyngitis caused by coronavirus usually manifests as the common cold. As in rhinovirus colds, viral mucosal invasion of the respiratory tract does not occur.

Enterovirus

The major groups of enteroviruses that can cause pharyngitis are coxsackievirus and echovirus. Although enteroviruses are primarily transmitted by the fecal-oral route, airborne transmission is important for certain serotypes. Enteroviral lesions in the oropharyngeal mucosa are usually a result of secondary infection of endothelial cells of small mucosal vessels, which occurs during viremia following enteroviral infection in the GI tract.

Respiratory syncytial virus

Transmission of respiratory syncytial virus (RSV) occurs by fomites or large-particle aerosols produced by coughing or sneezing. The pathogenesis of RSV infection remains unclear, although a number of theories exist. Immunologic mechanisms may contribute to the pathogenesis of the severe disease in infants and elderly patients.

Cytomegalovirus

Acute acquired cytomegalovirus (CMV) infection is transmitted by sexual contact, in breast milk, via respiratory droplets among nursery or day care attendants, and by blood transfusion. Infection in the immunocompetent host rarely results in clinically apparent disease. Infrequently, immunocompetent hosts exhibit a mononucleosislike syndrome with mild pharyngitis.

Human immunodeficiency virus

Pharyngitis develops in patients infected with human immunodeficiency virus (HIV) as part of the acute retroviral syndrome, a mononucleosislike syndrome that is the initial manifestation of HIV infection in one half to two thirds of recently infected individuals.

Frequency

United States

Each year, pharyngitis is responsible for more than 40 million visits to health care providers. Most children and adults experience 3-5 viral upper respiratory tract infections (including pharyngitis) per year.

International

Worldwide, acute infections of the respiratory tract are one of the main causes of disease, and most of these are due to viruses.

Mortality/Morbidity

Worldwide, viral pharyngitis is one of the most common causes of absence from school or work. The National Ambulatory Medical Care Survey showed that upper respiratory tract infections, including acute pharyngitis, accounted for 200 annual visits to a physician per 1000 population between 1980-1996. The vast majority of upper respiratory tract infections are due to viruses.

Race

Viral pharyngitis affects all races and ethnic groups equally.

Sex

Viral pharyngitis affects both sexes equally.

Age

Viral pharyngitis affects both children and adults, but it is more common in children. For more information on pediatric pharyngitis, see the eMedicine article Pharyngitis in the Pediatrics: General Medicine volume.

Clinical

History

Sore throat is the chief symptom in patients with viral pharyngitis. Patients may have additional symptoms that vary based on the causal pathogen. These symptoms are generally not useful in discriminating between the causes of viral pharyngitis because the symptoms produced by the numerous viruses that cause pharyngitis are so similar and commonly overlap each other.

• Pharyngitis in the common cold syndrome: Sore throat is usually not the primary symptom. Nasal symptoms, such as sneezing, watery nasal discharge, nasal congestion, or postnasal discharge, tend to precede throat symptoms. Throat symptoms can be in the form of soreness, scratchiness, or irritation. Nasal discharge may be thick and yellow. Nonproductive cough may be present. Fever, if present, is usually low grade and is more prominent in young children than in adults. Hoarseness is sometimes present. Severe pharyngeal pain or odynophagia is unusual. Chills, myalgia, and profound malaise are usually not prominent.
• Pharyngitis caused by adenovirus: Pharyngitis caused by adenovirus is common among young children and military recruits. Patients with pharyngitis present with sore throat (more intense than that of a common cold), high fever, dysphagia, and red eyes. Red eyes are due to concurrent conjunctivitis, which occurs in one third to one half of affected patients, along with fever. This syndrome is named pharyngoconjunctival fever. The patient may have a history of swimming pool exposure approximately 1 week before the onset of illness. Military personnel tend to be more ill with hoarseness, chest pain, and respiratory distress.
• Pharyngitis associated with EBV infectious mononucleosis: EBV infectious mononucleosis is most commonly observed in adolescents and young adults. Sore throat and fatigue are the most common symptoms. Pharyngeal symptoms are usually associated with other features of the disease (eg, fatigue, skin rash, anorexia).
• Acute herpetic pharyngitis: Acute herpetic pharyngitis is most commonly observed in children and young adults. Sore throat may be accompanied by sore mouth with associated gingivostomatitis. Other symptoms include fever, myalgia, malaise, inability to eat, and irritability.
• Pharyngitis with influenza: Sore throat is the chief symptom in some patients with influenza. The onset of illness is usually abrupt, with myalgia, headache, fever, chills, and dry cough. The pharyngitis usually resolves in 3-4 days. Cases generally occur in an epidemic pattern, usually in late fall or winter in North America.
• Pharyngitis caused by enteroviruses: Enteroviruses are an important cause of viral pharyngitis in childhood. This condition has a peak occurrence in late summer and early fall. Distinctive clinical syndromes include (1) herpangina caused by coxsackievirus A2-6; (2) acute lymphonodular pharyngitis caused by coxsackievirus A10; (3) hand-foot-and-mouth disease caused by coxsackievirus A5, 9, 10, and 16, and enterovirus 71; and (4) Boston exanthem caused by echovirus type 16.
  • Young children with herpangina have sore throat, sore mouth, and severe odynophagia. Sudden onset of fever (temperature of up to 106°F/41°C), coryza, and anorexia are common presenting symptoms. Twenty-five percent of children vomit. Older children develop neck pain, headache, and back pain. Herpangina is not associated with gingivitis, in contrast to acute herpetic pharyngitis.
  • Children with hand-foot-and-mouth disease have low-grade grade fever (temperature, 100-102°F/38-39°C), sore throat, sore mouth, anorexia, malaise, and rash on the hands and feet.
  • Children with Boston exanthem have sudden onset of fever, sore throat, nausea, and rash over the face and trunk.
• Pharyngitis caused by RSV: Immunocompetent adults with RSV infection present with nasal discharge, sore throat, low-grade fever, and cough. Infants, elderly persons, and patients with chronic obstructive pulmonary disease (COPD) or congestive heart failure are more likely to develop lower respiratory tract involvement, which manifests as dyspnea, wheezing, and respiratory failure. Outbreaks of illness occur during the fall, winter, and early spring.
• Pharyngitis caused by CMV: Patients who have CMV infection tend to be older than those with EBV infectious mononucleosis. Sore throat is less salient, but fever and malaise are prolonged and are more prominent than in EBV infectious mononucleosis.
• Pharyngitis caused by HIV: Patients with primary HIV infection (acute retroviral syndrome) develop acute sore throat similar to infectious mononucleosis. Sore throat is usually accompanied by other symptoms. Fever, sweats, malaise, lethargy, myalgias, anorexia, nausea, diarrhea, and skin rash are prominent symptoms.

Physical

Edema and erythema of the pharynx are typical in viral pharyngitis. The degree of erythema does not correlate with the degree of soreness. Exudate can be present but is generally less effusive than in bacterial pharyngitis.

• Pharyngitis in the common cold syndrome: Redness around the external nares from nose blowing may be noted. Nasal mucosa is often erythematous. Mild erythema of the pharynx is usually present.
• Pharyngitis caused by adenovirus: Examination of the oropharynx reveals pharyngeal erythema with exudates. When associated with conjunctivitis, both bulbar and palpebral conjunctivae are involved without purulent discharge. The palpebral conjunctivae usually have a granular appearance. Although the onset is frequently monocular, the other eye usually becomes involved. Conjunctivitis often persists after fever and other symptoms have resolved. Preauricular and cervical lymphadenopathy may be present.
• Pharyngitis associated with infectious mononucleosis
  • Examination of the oral cavity and pharynx reveals the characteristic marked enlargement of the tonsils. Half of patients with infectious mononucleosis have a coating of thick, continuous exudates, mimicking streptococcal pharyngitis. The uvula may also be swollen. Unilateral palatal swelling and tenderness may be present.
  • Palatal petechiae may be observed in both infectious mononucleosis and streptococcal pharyngitis. However, palatal petechiae associated with infectious mononucleosis tend to be confined to the soft palate. Fever may reach a temperature of up to 104°F/40°C. Periorbital edema is common.
  • Tender lymphadenopathy is most prominent in the posterior and anterior cervical regions, but axillary and inguinal nodes may also be enlarged. Splenomegaly is present in 50% of patients; hepatomegaly in approximately 10-15%; jaundice in 5%; and a fine, variable form rash in about 5%. More than 90% of patients given ampicillin develop a diffuse, pruritic maculopapular eruption.
• Acute herpetic pharyngitis: Examination of the oral cavity and pharynx shows characteristic painful shallow ulcers with red margins or vesicles on the hard and soft palates, posterior pharynx, and tonsillar pillars. Exudates may be present on the lesions. These lesions can be present on the tongue, gingiva, lips, or buccal mucosa with an associated gingivostomatitis. Lesions on the tongue, gingiva, or buccal mucosa may appear late in the course in one third of cases. Fever and tender cervical lymphadenopathy are common. Fever may reach temperatures of up to 106°F/41°C in children younger than 5 years. Clinically differentiating acute herpetic pharyngitis from bacterial pharyngitis can be difficult.
• Pharyngitis with influenza: Edema and erythema of pharyngeal mucosa may be present but usually to a mild degree. Pharyngeal or tonsillar exudates and cervical lymphadenopathy are absent. Fever with temperatures of up to 104°F/40°C is common. Profound fatigue and conjunctival injection are usually prominent.
• Enteroviral pharyngitis
  • Herpangina is characterized by multiple small vesicles (1-2 mm) on the tonsils, tonsillar pillars, uvula, or soft palate. Vesicles may enlarge to 4 mm or have an erythematous ring as large as 10 mm. Vesicles become shallow ulcers in about 3 days and then heal. The remainder of the pharynx is usually normal.
  • Boston exanthem is characterized by pharyngeal erythema and a roseolalike salmon-pink maculopapular rash over the face and trunk.
• Pharyngitis caused by CMV: Physical findings in CMV mononucleosis syndrome are similar to those in EBV infectious mononucleosis except for less prominent pharyngeal signs. The pharynx may be mildly erythematous or almost normal in appearance. Splenomegaly is less common and prominent than in EBV infectious mononucleosis.
• Pharyngitis caused by HIV: Examination of the oral cavity and pharynx reveals tonsillar hypertrophy without exudate. Cervical, occipital, or axillary lymphadenopathy is a frequent manifestation; hepatosplenomegaly is less common. Oral aphthous ulcerations have been reported in several cases. A rash that may be maculopapular, roseolalike, or urticarial develops in 40-80% of patients.

Causes

• Rhinovirus and adenovirus are the most common etiological agents, and each accounts for 6-20% of all cases of pharyngitis, both viral and nonviral.
• Less common etiological agents include EBV, HSV, influenza virus, parainfluenza virus, and coronavirus.
• Uncommon etiological agents include enterovirus (eg, poliovirus, coxsackievirus, echovirus), RSV, CMV, rotavirus, reovirus, rubella virus, varicella-zoster virus, measles virus, and HIV-1.

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