May 2000
SAN FRANCISCO - Exanthems in children may aid in the diagnosis of several diseases of varying severity.
"It's very important that we recognize these things and can diagnose them promptly," said Anthony J. Mancini, MD, assistant professor of pediatrics and dermatology at Northwestern University Medical School in Chicago. "We need to know whether further evaluation is indicated, whether there may be any systemic implications of the rash we're seeing on the skin, and whether it brings up any epidemiologic concerns."
Several epidemiologic factors should be considered along with the exanthem when making a diagnosis. Day care setting, school setting, time of year and age of the child may all be important.
"A lot of these may present in distinct age ranges," said Mancini, who spoke here at the American Academy of Dermatology 58th Annual Meeting. Fever, lymphadenopathy and other organ involvement may also yield clues, as will type, distribution and natural course of the lesions.
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Enteroviruses are the leading cause of exanthematous illness in children during the summer and fall, Mancini said. Gastrointestinal manifestations such as diarrhea are a common finding, and enterovirus transmission is primarily through the fecal-oral route. More serious manifestations, such as meningitis and encephalitis can also be associated with enteroviruses, as can cardiac manifestations, including cardiomyopathy.
Exanthems caused by enteroviruses may present with bland erythematous macules and papules or with blistering. Petechial eruptions may also be present, especially with echovirus-9 infection, Mancini said.
"This illness may occasionally require differentiation from more serious disorders such as meningococcemia, especially when the child presents with meningeal signs and a petechial rash," he said.
Diagnosis of enteroviral infections has generally relied on cell culture of swabs obtained from the nasal pharynx or the rectum. Cultures of the cerebrospinal fluid or newer polymerase chain reaction studies may be useful as well.
Kawasaki syndrome can be problematic to diagnose and fatal if untreated. "Its presentation can significantly overlap the spectrum of other exanthems we see in kids," Mancini said. Additionally, "it's now the primary cause of acquired heart disease in children in the United States."
Eighty percent of patients with Kawasaki syndrome are younger than 5, and peak incidence occurs in children younger than 2. Children of Asian ancestry are at a particularly high risk.
Criteria for diagnosis include fever lasting five days, oropharyngeal changes (including lip swelling, fissuring and crusting), extremity changes such as swelling or induration, a polymorphous cutaneous eruption and cervical lymphadenopathy. Another common cutaneous finding in patients with Kawasaki syndrome is an erythematous desquamating rash in the perineum. Nonpurulent conjunctivitis is another diagnostic criterion, but observation of purulent conjunctivitis mitigates against the diagnosis of Kawasaki syndrome, Mancini said.
Arthralgias, abdominal pain and hydrops of the gall bladder have all been associated with Kawasaki syndrome, along with aseptic meningitis, facial nerve palsy and hearing loss. Thrombocytosis may occur later in the course of the disease, and erythrocyte sedimentation rate may remain elevated throughout the course of the disease.
The etiology of Kawasaki syndrome remains unknown, and treatment used to consist of daily infusions of gamma globulin. Recent studies, however, have documented equal efficacy of a single infusion of intravenous gamma globulin in a dose of 2 mg/kg over 10 to 12 hours. Aspirin is administered at a dose of 80 mg/kg/day to 100 mg/kg/day until fever abates. Low-dose aspirin is then maintained until the markers of inflammation (i.e. erythrocyte sedimentation rate) return to normal.
Echocardiograms should be conducted at baseline and two to three weeks later. If a cardiac echo at six to eight weeks does not reveal coronary aneurysms, further cardiac follow-up is usually not needed, Mancini said.
While at one time as many as one-quarter of patients suffered from coronary aneurysms, use of gamma globulin has reduced the incidence to around 2%-4%, Mancini said.
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1. Petechial eruption associated with
enteroviral infection. 2. Perineal erythema in a patient with Kawasaki
syndrome. 3. Lacy, reticulate erythema on the thighs of a girl with erythema
infectiosum. 4. Erythematous macules and papules of the left arm in a patient
with unilateral laterothoracic exanthem. Photos courtesy of Anthony J. Mancini, MD |
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Human parvovirus B19 is the cause of erythema infectiosum, or fifth disease, in children.
Bright red erythema on the cheeks is the primary feature of the disease. "As that fades, you begin to see the classic reticular lacy rash," Mancini said. In some patients, the rash of fifth disease may persist for several months.
Primary infection occurs in the respiratory tract and generally takes place one to two weeks preceding the rash. In some cases, the eruption may appear similar to that seen in patients with juvenile rheumatoid arthritis.
Significant arthralgias may be observed, although this is more of a problem in the adult population, Mancini said. About 10% of children with human parvovirus B19 infection may have joint involvement, compared with up to 50% of adults, most notably adult females.
Recurrent infection has been documented in otherwise immunocompetent hosts, and persistent infection has been seen in immunocompromised patients. One of the most important associations with parvovirus B19 infection is potential transmission to the fetus when a nonimmune pregnant female is exposed. The greatest risk of exposure is prior to the third trimester, and potential complications include fetal anemia, nonimmune hydrops and fetal demise.
Edematous red papules measuring 1 mm to 5 mm are usually present with Gianotti Crosti syndrome, and distribution is key.
"These patients may have an upper respiratory prodome, and the lesions are very monomorphous," Mancini said.
"They're usually limited to a few locations: the cheeks, the extensor surfaces of the extremities and the buttocks," Mancini said. "There is usually complete or at least nearly complete sparing of the trunk."
The lesions may last up to three months, and treatment is primarily symptomatic. "It's going to take a long time to go away, and nothing is really going to speed that up," Mancini said. "Topical corticosteroids make very little difference."
Thorough evaluation for gastrointestinal symptomatology, palpation of the liver and spleen and looking for lymphadenopathy are important when evaluating a patient with the disease. "If there's anything suggestive of hepatitis, then we may want to check for this infection, but I do not routinely recommend blind evaluations for hepatitis in these kids," Mancini said. He continued that Gianotti Crosti syndrome is attributed to a variety of viral agents in this country, most commonly Epstein-Barr virus.
Hepatitis has been rarely associated with Gianotti Crosti syndrome in the United States, and a 1992 study in Italy found a hepatitis prevalence of 20% among children with the disease.
Unilateral laterothoracic exanthem generally presents in children 1 to 4 years of age. The disease initially presents in a unilateral very localized distribution, usually in the axilla or thoracic portions of the trunk, although it may also present on the thigh or leg. It is frequently misdiagnosed.
"The most common initial misdiagnosis I've seen is that of contact dermatitis," Mancini said.
For more information:
- Mancini A. Viral infections. Session CRS103. Presented at the American Academy of Dermatology 58th Annual Meeting. March 10-15, 2000. San Francisco.
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