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Coxsackieviruses, Echoviruses, and Numbered Enteroviruses (EV-A71, EVD-68, EVD-70)
This chapter covers human disease caused by the group A coxsackieviruses (CVs), group B CVs, echoviruses (Es), and the numbered enteroviruses (EVs), which are distributed among four species, EV-A to EV-D, of the genus Enterovirus. Viral diseases caused by the closely related and newly designated genus Parechovirus , of the Picornaviridae, are discussed in Chapter 173 . These viruses have many physical, epidemiologic, and pathogenetic characteristics in common, as described in Chapter 170 . Greater than 90% of infections caused by the nonpolio EVs are asymptomatic or result only in undifferentiated febrile illness. When disease occurs, the spectrum and severity of clinical manifestations vary with the age, gender, and immune status of the host and with the subgroup, serotype, and even the intratypic EV strain.
Some clinical syndromes (viral meningitis and some exanthems) are caused by many EV serotypes, some are predominately caused by certain EV serotypes (e.g., pleurodynia and myocarditis by the group B CVs), and other diseases are mostly associated with individual EV serotypes. Infections caused by some of the more recently recognized serotypes are discussed at the end of this chapter.
Central Nervous System Infections
Acute Viral Meningitis
Viral infection is the dominant cause of the aseptic meningitis syndrome, and the EV-B species, which encompass all of the group B coxsackievirus (CV-B) and echovirus (E) serotypes, cause most acute viral meningitis cases in both adults and children. Group A coxsackieviruses (CV-A) cause relatively fewer cases. Historically, CV-B2 to CV-B5 and E-4, -6, -7, -9, -11, -13, -16, -18, -30, and -33 are the most frequently implicated serotypes. On occasion a single E serotype may cause widespread outbreaks; for example, E-13 caused outbreaks of aseptic meningitis throughout Europe and the United States in 2000 and 2001, and E-33 caused widespread disease in New Zealand during the winter of 2000.
Clinical Manifestations
Infants younger than 3 months have the highest rates of clinically recognized aseptic meningitis, in part because lumbar punctures are routinely performed for evaluation of fever in this age group. Only a minority of these infants have clinical manifestations suggestive of neurologic disease.
The severity of disease in older children and adults with aseptic meningitis varies widely. The onset may be gradual or abrupt, and the typical patient has a brief prodrome of fever and chills. Headache is usually a prominent complaint. Meningismus, when present, varies from mild to severe. Kernig and Brudzinski signs are present in only about one-third of patients. Signs of meningeal irritation are less frequently observed in young infants than adults. Pharyngitis and other symptoms of upper respiratory tract infections are often present. The illness is sometimes biphasic, as in poliomyelitis; these patients present with a prodromal illness with fever and myalgias, followed by defervescence and absence of symptoms for a few days, and then experience abrupt recurrence of fever with headache and other signs of meningismus. Complications such as febrile seizures, complex seizures, lethargy, coma, movement disorders, and development of a syndrome of inappropriate antidiuretic hormone secretion occur early in the course of aseptic meningitis in 5% to 10% of patients. Adults may experience a more prolonged period of fever and headache than infants and children, and some adult patients may take weeks to return to normal activity.
Laboratory Diagnosis
The clinical diagnosis of viral meningitis depends on routine examination of cerebrospinal fluid (CSF). The CSF is clear and under normal or mildly increased pressure. The total CSF cell count is usually 10 to 500/mm 3 but may occasionally exceed 1000/mm 3 . Cell counts less than 10 cells/mm 3 may occur. Absence of pleocytosis may occur in 18% to 30% of infants and children with EV meningitis detected by nucleic acid amplification testing (NAAT) and occurs more frequently in neonates and young infants. Differential cell counts of the CSF often first reveal a high proportion of neutrophils, but the differential typically shifts to a predominance of lymphocytes during the initial 1 to 2 days of illness. In general, the CSF glucose concentration is normal, and the CSF protein concentration is normal or slightly elevated. However, the glucose content may be lower than normal in 18% to 33% of cases, and values less than 40 mg/dL may occur. Uncommonly, it may be difficult to exclude bacterial meningitis on the basis of the CSF profile alone. In some cases the CSF findings may closely mimic those of tuberculous meningitis.
NAATs (e.g., reverse-transcriptase polymerase chain reaction [RT-PCR] and nucleic acid sequence-based amplification [NASBA]) have replaced cell culture as the primary means of detection of EVs in CSF and other specimens. Most PCR protocols amplify a highly conserved portion of the 5′ nontranslated region of the genome, which enables the detection of the majority of EVs. For confirmed or suspected enteroviral meningitis cases, PCR sensitivity ranges from approximately 70% to greater than 90%. The overall sensitivity of virus isolation from the CSF of patients with viral meningitis is typically 30% to 35%, although higher figures have been reported during some E outbreaks. Concomitant testing of serum, upper respiratory secretions, urine, and stool enhances the likelihood of virus detection by either PCR or cell culture.
Differential Diagnosis
Bacterial meningitis is the most important disease to be distinguished from EV aseptic meningitis. Although some clinical features of bacterial meningitis that is incompletely treated with antibiotics may overlap those of EV aseptic meningitis, when therapy has been instituted before lumbar puncture, several studies have demonstrated that pretreatment of bacterial meningitis alters the CSF minimally. Even when some laboratory indicators are altered by therapy (i.e., change from polymorphonuclear to lymphocytic pleocytosis), others continue to indicate bacterial disease (i.e., low glucose or high protein concentration). Arboviruses, lymphocytic choriomeningitis virus, leptospirosis, Lyme borreliosis, and acute human immunodeficiency virus infection account for most of the remaining cases of infectious aseptic meningitis. Mumps virus infection was a common cause of aseptic meningitis before the introduction of mumps vaccine in the United States. Aseptic meningitis also occurs with other infectious and noninfectious diseases (see Chapter 88 ), but the etiology is usually suggested by other clinical features.
Management and Prognosis
Although hospitalization is not necessary for all cases in adolescents and adults and, indeed, may not be feasible during summer epidemics of EV infections, it is advisable when disturbances in consciousness, muscle weakness, or a petechial or purpuric rash suggest the possibility of a more serious illness. Pyogenic bacterial meningitis should be excluded by lumbar puncture. When bacterial meningitis cannot be excluded because of prior antibiotic treatment, administration of appropriate antibiotics is advisable after performing Gram stains and bacterial cultures. CSF EV NAAT may be useful in deciding whether to continue administration of antibiotics and hospitalization if the test can be reported within 1 to 2 days.
In most cases treatment consists only of relief of symptoms. Analgesics are usually given to older children and adults to alleviate headache and lassitude, and easy fatigability may be present for weeks after acute illness. Pleconaril, an experimental orally administered EV capsid-stabilizing drug, modestly reduced the duration of headache and other symptoms in clinical trials but has not been further developed for this purpose. Treatment studies of infants and young children, who generally experience a shorter duration of symptoms, have been inconclusive.
In one large study of EV aseptic meningitis, subtle disturbances in motor function (limitation of passive motion, muscle spasm, and poor coordination) were observed during convalescence. These abnormalities slowly resolve and are rarely detectable 1 year after infection. In young children fever and signs of meningeal irritation subside in a few days to 1 week. Infants younger than 3 months may have fewer symptoms of illness and fewer complications than older infants. Although some investigators have suggested that EV meningitis in the first year of life may result in permanent neurologic sequelae, studies of larger numbers of children using more rigorous methods indicate that the long-term prognosis for the youngest infants is also excellent.
Encephalitis
Encephalitis is a well-documented manifestation of nonpolio EV central nervous system (CNS) infection. In industrialized nations the EVs account for less than 5% of all encephalitis cases but may contribute to a larger proportion in developing nations. EVs account for 11% to 22% of encephalitis cases that are proved to be viral. Numerous serotypes have been implicated as causes of encephalitis; CV-A9 and CV-A16, CV-B2 and CV-B5, E-6 and E-9, and EV-A71 are the serotypes reported most often, but the evidence linking each of these serotypes to encephalitis is highly variable. A notable exception is that of EV-A71, where it has unambiguously been linked to encephalitis. In a minority of cases a specific etiology has been proved by isolating virus or detecting its genome in brain tissue or CSF; in others the cause of encephalitis has been inferred by isolating virus from a nonneurologic site or by serology.
In perinatally acquired EV infection, encephalitis is often only one manifestation of generalized viral disease, but beyond the neonatal period, signs and symptoms are generally limited to the CNS. Children and young adults are most frequently affected. CNS disease varies from relatively mild encephalopathic symptoms in patients with EV meningitis to severe generalized encephalitis with seizures, paresis, and coma. Children with focal encephalitis present with partial motor seizures, hemichorea, and acute cerebellar ataxia, features that in some cases have suggested a diagnosis of herpes simplex virus (HSV) encephalitis.
EV-A71 and, rarely, other EV serotypes are the cause of a severe, often fatal form of brainstem encephalitis (rhombencephalitis) with secondary cardiopulmonary manifestations, including noncardiogenic pulmonary edema. EV-A71 encephalitis has a strikingly high prevalence in countries of the Asia–Pacific Rim. Multiple large outbreaks have occurred in this region of the world in the last 10 to 15 years. The disease affects principally infants and toddlers. CNS disease is usually preceded by hand-foot-and-mouth disease (HFMD) or herpangina. In addition to the neurologic signs of encephalitis mentioned previously, myoclonus occurs frequently. The use of glucocorticoids and/or pyrazolones may be risk factors for the development of life-threatening disease.
The CSF findings in EV encephalitis are similar to those in aseptic meningitis. Magnetic resonance imaging (MRI) of the brain and electroencephalography may demonstrate either generalized or localized abnormal signals, reflecting the extent and severity of brain involvement. Most patients with CV and E encephalitis beyond the neonatal period recover fully, although permanent neurologic sequelae and rare deaths occur. EV-A71 encephalitis may be associated with such sequelae as limb atrophy and weakness, as well as long-term behavior problems in children.
Acute Flaccid Paralysis/Myelitis and Other Neurologic Complications
The clinical presentation of acute flaccid paralysis (AFP) mimics that of poliomyelitis. For some EV serotypes the link with AFP has been established through detection of the virus or its nucleic acid in the CSF or CNS tissue of affected individuals. In the majority, however, the link is inferential by viral detection in stool, respiratory tract, or by an increase in virus-specific antibodies. The detection of AFP for monitoring the progress of polio eradication has led to an increase in the identification of serotypes inferentially associated with this syndrome. EV-A71 has been associated with large outbreaks of AFP in Russia, Eastern Europe, Thailand, and Taiwan. CV-A7, which is neuropathogenic in monkeys, has also been associated with outbreaks of AFP. Sporadic cases of AFP have been associated with multiple serotypes from EV-A, EV-B, and EV-C spp., in decreasing order of frequency.
Recently, a cluster of acute flaccid myelitis (AFM) temporally associated with an outbreak of EV-D68 respiratory disease characterized by asymmetrical limb weakness/paralysis, bulbar weakness, and cranial nerve dysfunction drew an inferential link between the two. Nationwide surveillance for cases of AFP further pointed to a possible association between EV-D68 and AFP. Although EV-D68 has rarely been identified from the CSF, evidence for the causality of EV-D68 and AFP was further supported by the Bradford Hill criteria. As a result of the bulbar weakness and paralysis of the muscles of respiration, inability to protect the airway and respiratory failure secondary are frequently seen. EV-D68 is rarely isolated from the CSF of cases of AFM but can be found in the nasopharynx and stool of infected individuals. Cytochemical analysis of the CSF demonstrates a lymphocytic pleocytosis in the majority of cases. CSF protein and glucose concentrations are generally increased and normal, respectively. MRI findings included longitudinally extensive nonenhancing lesions of the gray matter in the spinal cord or brainstem, the cervical spinal cord being the most commonly involved segment. Electrodiagnostic studies of affected limbs demonstrate motor neuropathy or neuronopathy without sensory abnormalities. The majority of patients with AFM will experience persistent sequelae. A national survey of AFP documented that only 5% of respondents reported complete recovery of strength, and only 18% were fully functional.
Treatment of EV-D68 associated AFM is supportive. Antiviral agents that inhibit EVs, such as pleconaril, pocapavir, and vapendavir, do not have in vitro antiviral activity against EV-D68. Fluoxetine, a selective serotonin reuptake inhibitor, has been shown to be active in vitro against EV-B and EV-D spp., including EV-D68, failed to show activity against EV-D68 in a murine model (also see Chapter 48 ).
Paralytic disease caused by the nonpolio EVs, other than EV-A71 and EV-D68, is characteristically less severe than poliovirus-associated paralysis. Prodromal fever or presence of fever at the time of onset of paralysis and residual paralysis or atrophy are less frequently encountered in paralytic disease due to the nonpolio EVs. Muscle weakness is more common than flaccid paralysis.
Cranial nerve involvement has occasionally resulted in complete unilateral oculomotor palsy. Guillain-Barré syndrome has been reported in a small number of patients in association with CV-A2, CV-A5, and CV-A9 and with E-6 and E-22. In a few cases the implicated virus has been isolated from CSF or the brainstem. Transverse myelitis caused by CV-B4, CV-A9, and E-18, and has been reported in patients who had rises in neutralizing antibody and in patients who had E-5 and CV-B5 recovered from CSF. Systemic CV-B2 disease has been reported with many of the clinical features of Reye syndrome. Furthermore, several children with well-documented Reye syndrome have had a variety of EVs isolated concurrently from multiple sites, including the brain and CSF. However, a clear etiologic or epidemiologic link between EV infection and Reye syndrome has not been established. Opsoclonus-myoclonus, or the “dancing eyes” syndrome, has been reported in two children with concurrent CV-B3 infection and in an adult with EV-A71 infection.
Exanthems
CVs and Es cause a variety of exanthems, which are sometimes associated with enanthems. With the exception of HFMD, these rashes are not sufficiently distinctive to permit a reliable etiologic diagnosis on clinical grounds alone. Virus can be isolated from the vesicular lesions of patients with HFMD, and therefore these lesions appear to be a direct result of viral invasion of the skin after viremia. No attempts at isolation of virus from the skin in cases of maculopapular and petechial exanthems have been reported; in consequence, it is not known whether these lesions are also caused by the virus directly or by immunopathologic mechanisms.
EV exanthems themselves cause little morbidity. They are important as sentinels of the prevalence of CVs and Es in the community and because they are often confused with other infective exanthems, some of which have more serious implications. Rashes caused by EVs may be grouped according to the type of exanthem that they mimic: rubelliform or morbilliform, roseoliform, vesicular, or petechial. Some overlap between these types of exanthems may be observed in different patients infected with the same EV or even among different morphologic lesion types in the same patient.
Rubelliform and Morbilliform Exanthems
Overall, EVs account for about 5% of acute morbilliform exanthems that occur in populations with high measles and rubella vaccine coverage. Maculopapular rashes resembling rubella commonly occur during summer E epidemics. High attack rates have been noted with E-9, the most common serotype associated with rubelliform rash. In one epidemic 57% of persons younger than 5 years with illness caused by E-9 had rash, 41% of those 5 to 9 years of age had rash, but rash affected only 6% of those older than 10 years. The rash, which characteristically appears simultaneously with fever, begins on the face and then spreads to the neck, chest, and extremities. The illness may be distinguished from rubella by the absence of pruritus and posterior cervical lymphadenopathy. In occasional patients with an enanthem resembling Koplik spots and a blotchy eruption, the disease may be confused with measles, but the coryza and conjunctivitis characteristic of that disease are absent.
Roseoliform Exanthems
These EV exanthems are distinctive, not in their appearance but in their timing; as in roseola, the rash does not appear until defervescence. The prototype is the “Boston exanthem,” the first of the EV exanthems to be recognized and now known to be caused by E-16. Multiple cases often occur sequentially in families, with rash developing in as many as one-fourth of the children in a household who are mildly ill with low-grade fever and pharyngitis. The fever lasts 24 to 36 hours and then declines simultaneously with the appearance of discrete, nonpruritic, salmon-pink macules and papules about 1 cm in diameter on the face and upper part of the chest. The extremities are less commonly involved. The duration of the rash is 1 to 5 days. Other EV serotypes (CV-B1 and CV-B5, E-11 and E-25) have also been associated with roseola-like illness. Exanthem subitum (roseola infantum), a common nonseasonal exanthem in which the rash typically develops as the fever declines, is caused by human herpesvirus 6 (see Chapter 139 ).
Herpetiform Exanthems
Hand-Foot-and-Mouth Disease
HFMD is primarily associated with EV-A serotypes (CV-A4, -A5 to -A7, -A10, -A16, -A24; EV-A71), although EV-B serotypes (CV-A9, CV-B2 to CV-B5; E-4, E-18, E-19) are also associated with sporadic cases. CV-A16 and EV-A71 are the most common causes of this distinctive vesicular eruption, also known as vesicular stomatitis with exanthema ( Fig. 172.1A–C ). In Southeast Asia the latter serotype has caused large outbreaks associated with severe CNS disease and deaths. In recent years reports of outbreaks of HFMD caused by CV-A6 and CV-A10 have come from Europe, Asia, and the United States.
Children younger than 10 years are often affected, and spread to other family members occurs commonly. Most patients complain of sore throat or sore mouth, and affected young children may refuse to eat. Temperatures of 38°C to 39°C last 1 to 2 days and are accompanied in essentially all cases by vesicles in the oral cavity, occurring chiefly on the buccal mucosa and tongue. Several lesions may coalesce to form bullae and ulcerate. Peripherally distributed cutaneous lesions occur in roughly 75% of patients, commonly on the extensor surfaces of the hands and feet and sometimes on the buttocks or genitalia. The lesions are tender and consist of mixed papules and clear vesicles with a surrounding zone of erythema. Skin biopsy demonstrates subepidermal lesions with a mixed lymphocytic and polymorphonuclear inflammatory response and acantholysis of the overlying epidermis. Eosinophilic nuclear inclusions and intracytoplasmic picornavirus particles can be seen microscopically within cells surrounding dermal vessels.
The vesicular lesions of HFMD disease superficially resemble those caused by herpes simplex or varicella-zoster virus (VZV). Patients with HFMD invariably have lesions of the oral mucosa. In contrast, oral lesions are less common in patients with chickenpox; moreover, these patients generally appear more ill, and their cutaneous lesions are more extensive and centrally distributed, generally with sparing of the palms and soles. Patients with primary herpetic gingivostomatitis also usually appear more ill and have a higher fever and cervical lymphadenopathy; lesions are usually confined to the oral cavity and do not involve the extremities. The enanthem of herpangina also resembles HFMD, but it occurs in the posterior oropharynx and typically involves the fauces and soft palate.
An atypical form of HFMD, caused by a novel CV-A6 strain, has been observed since 2008 in multiple locations globally and is characterized by a wider distribution of skin lesions that enlarge and vesiculate, especially in areas of eczematous skin. Generalized varicella form–like eruptions have also been reported in association with CV-A6 infection. The acute disease is associated with a higher rate of hospitalization than typical HFMD, but it has an invariably benign outcome, with the exception of onychomadesis (loss of fingernails), which occurs in many cases 1 to 2 months after the infection. Generalized vesicular eruptions occurring in crops of lesions are also reported in association with CV-A9 and E-11 infection, and one case with disseminated lesions has been described in an infant with preexisting atopic eczema; the condition was given the sobriquet “eczema coxsackium,” by analogy with eczema herpeticum and eczema vaccinatum. Unlike HSV and VZV infection, the vesicles do not evolve to form pustules and scabs. Vesicular eruptions caused by E-11 have occurred in immunocompromised adult patients. An acute eruption resembling dermatomal zoster, in which E-6 was isolated from the bullous lesions, has been reported.
Petechial Exanthems and Other Cutaneous Manifestations
Petechial and purpuric rashes have been described with E-9 and CV-A9 infections. When these rashes have a hemorrhagic component, the illness is easily confused with meningococcal disease, especially if aseptic meningitis occurs simultaneously. On occasion, cutaneous eruptions of CV-A9 disease have an urticarial nature. One child was reported to have papular acrodermatitis (Gianotti-Crosti syndrome) in association with CV-A16 infection.
Acute Respiratory Disease (EV-D68)
EVs account for most viruses recovered from children with summertime upper respiratory tract infections, including undifferentiated febrile illnesses (“summer grippe”) with sore throat and on occasion cough or coryza. EV upper respiratory tract illnesses are generally clinically indistinguishable from disease caused by rhinoviruses, Mycoplasma pneumoniae and other respiratory tract agents, unless accompanied by aseptic meningitis, exanthem, or other clinical features suggesting EV infection.
Many EV serotypes are associated with upper respiratory tract disease. Among the best-characterized EV respiratory viruses are CV-A21 and CV-A24, which produce illness resembling the common cold, except for a higher incidence of fever. Outbreaks of CV-A21 illness are reported in military populations. Although epidemics in civilians have not been recognized, sporadic infections presumably account for the observed high antibody prevalence rates in the general population. Unlike most EVs, CV-A21 is more readily recovered from throat swabs than from feces. In volunteers receiving small-particle aerosols of the virus, illness has included not only coryza and sore throat but also tracheobronchitis and pneumonia. EV-D68 emerged in 2008–10 as a cause of clusters of upper and lower respiratory tract disease in Europe, Asia, and the United States. EV-D68 has been isolated primarily from respiratory specimens during the autumn months. Cases have been reported primarily in children but also occur in adults. Symptoms include no to low-grade fever, cough, wheezing, shortness of breath, dyspnea, tachypnea, retractions, and hypoxia. Clinical syndromes associated with infection have included bronchiolitis, bronchitis, encephalitis, and pneumonia. In some, disease has been severe enough to warrant admission to the intensive care unit. Deaths have been reported. In 2014 the United States experienced a nationwide outbreak of EV-D68. From mid-August 2014 to January 2015, the Centers for Disease Control and Prevention (CDC) or state public health laboratories reported 1153 cases with respiratory illnesses caused by EV-D68 in 49 states and the District of Columbia. Almost all of the confirmed cases were in children, many of whom had asthma or a history of wheezing. There were likely many thousands of mild EV-D68 infections in individuals who did not seek medical attention and who were not tested for EV-D68. Of the 2600 specimens sent to the CDC for EV testing, approximately 36% tested positive for EV-D68, and 33% were positive for another EV or for rhinoviruses. Serious respiratory disease has also been reported in EV-D68 infection in adults, including infections in patients with hematalogic malignancies. The clinical syndromes seen in the 2014 outbreak of EV-D68 were primarily respiratory illnesses, typical of those seen in earlier outbreaks.
The CDC used a “real-time” reverse-transcriptase PCR that identifies all strains of EV-D68 that circulated in 2014. Genomic sequence of 2014 strains of EV-D68 showed that they are related to strains that circulated previously in the United States, Europe, and Asia. The majority of strains in the 2014 outbreak were classified as clade B, but interclade variations were also seen, which led to identification of strains that comprised a new clade D among EV-D68 strains.
E serotypes 4, 8, 9, 11, 20, 22, and 25 are also common causes of respiratory disease. E-11 produces sore throat, coryza, and cough and has also been associated with croup. The spectrum of CV-B respiratory disease includes coryza, laryngotracheobronchitis, bronchiolitis, and pneumonia. Pneumonia, which may be interstitial or a patchy bronchopneumonia, has occurred in children and rarely in adults. Severe lower respiratory tract EV infections are uncommon, although some EVs, notably E-6, -9, -11, and -33 and EV-A71, have been isolated after death from infants and young children with severe pneumonia.
Herpangina
Herpangina (herpes: vesicular eruption; angina: quinsy, or inflammation of the throat) is a well-characterized vesicular enanthem of the fauces and soft palate that is accompanied by fever, sore throat, and pain on swallowing ( Fig. 172.2 ). Despite the name, it has no relationship to HSV. Summer outbreaks of herpangina typically affect children age 3 to 10 years and, less commonly, adolescents and young adults. CV-A1 to -A10, -A16, and -A22 have been the most common viruses recovered from herpangina patients. Other serotypes include CV-B1 to CV-B5; CV-A6; E-3, -6, -9, -16, -17, -25, and -30; and EV-A71.
Clinical Manifestations
Herpangina begins suddenly with fever, vomiting, myalgia, and headache. Sore throat and pain on swallowing are prominent symptoms that precede appearance of the enanthem by several hours to a day. Examination of the throat reveals erythema and mild exudate of the tonsils and the characteristic enanthem, which begins as punctate macules and evolves over a 24-hour period to 2- to 4-mm erythematous papules that vesiculate and then ulcerate centrally. The moderately painful lesions, which are usually small in number, are located on the soft palate, uvula, and less commonly, on the tonsils; the posterior pharyngeal wall; or the buccal mucosa. The fever subsides in 2 to 4 days, but the ulcers may persist for up to a week. Patients with herpangina do not appear very ill and require only symptomatic treatment for sore throat.
A variant of the herpangina, termed acute lymphonodular pharyngitis, has been described in association with CV-A10 infection. Lesions occur in the same distribution as herpangina but consist of tiny nodules of packed lymphocytes that eventually recede without undergoing vesiculation or ulceration.
Differential Diagnosis
Herpangina is most often confused with bacterial tonsillitis or other viral causes of pharyngitis, herpetic gingivostomatitis, HFMD, and aphthous stomatitis. HSV gingivostomatitis occurs in the anterior oral cavity, especially on the inner aspects of the lips, the buccal mucosa, and the tongue. Gingivitis, prominent systemic toxicity, and cervical lymphadenitis are additional features of primary herpes simplex infection that are not seen in herpangina. In HFMD lesions also occur on the extremities in most cases. Aphthous stomatitis is characterized by recurrent large ulcerative lesions of the lips, tongue, and buccal mucosa among older children, adolescents, and adults.
Myositis
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