Though rarely life-threatening, rashes are a common reason for emergency department (ED) visits in children. Helpful clues to the specific diagnosis of rash in a child include signs and symptoms that preceded or presented with the exanthem, whether mucous membranes are involved, immunization history, human and animal contacts, and environmental exposures. Identifying outbreaks among multiple children may be useful. Pediatric exanthems can be broadly classified by etiologic agent. With few exceptions, outpatient management is appropriate for most of these conditions.
Enteroviruses include coxsackie viruses, echoviruses, and polioviruses with a diverse range of clinical presentations. Enterovirus infections typically occur in epidemics in the summer and early fall. Many enteroviral infections lack specific clinical syndromes and presentation may include fever, upper and lower respiratory tract symptoms, gastrointestinal symptoms, meningitis, and myocarditis. The rashes of enteroviral infections also have a variety of appearances, including diffuse macular eruptions, morbilliform erythema, vesicular lesions, petechial and purpural eruptions, rubelliform rash, roseola-like rash, and scarlatiniform eruptions.
One distinctive enteroviral infection is hand-foot-and-mouth disease. Initially, patients typically present with fever, anorexia, malaise, and a sore mouth. Oral lesions appear on days 2 or 3 of illness followed by skin lesions. The oral lesions start as very painful 4- to 8- mm vesicles on an erythematous base that then ulcerate. The typical location of the oral lesions is on the buccal mucosa, tongue, soft palate, and gingiva. Skin lesions start as red papules that change to gray—3- to 7-mm vesicles that ultimately heal in 7 to 10 days. Typical locations of skin lesions include the palms, soles, and buttocks. A similar enanthum without involvement of the hands and feet is caused by a different viral subtype and is known as herpangina (most commonly caused by coxsackievirus A).
Management of presumed enteroviral infections typically involves symptomatic therapy ensuring adequate hydration, antipyretics/analgesics, or a combined suspension of diphenhydramine liquid and Maalox® applied in small quantities to the lesions (or swish and spit) three times daily and before feeding. Occasional narcotics may be required to facilitate adequate outpatient hydration.
Due to immunizations, measles is no longer common, but recent outbreaks have occurred among unimmunized groups. Infection typically occurs in the winter and spring. The incubation period is 10 days, followed by a 3-day prodrome of upper respiratory symptoms and then malaise, fever, coryza, conjunctivitis, photophobia, and cough. Ill appearance is expected. Just before the development of a rash, Koplik spots, tiny white lesions on the buccal mucosa, may be seen with a “grains of sand” appearance that is pathognomonic for measles. The exanthem develops 14 days after exposure. Initially, a red, blanching, maculopapular rash develops. The rash progresses from the head to the feet and rapidly coalesces on the face, and lasts about a week. As the rash resolves, a coppery brown discoloration ...