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nonspecific viral exanthem in a child in whom other diagnoses have been excluded and who may have signs of associated illness or systemic features such as fever If specific diagnosis is required, it can be determined by viral isolation and/or a rise in diagnostic titer Generalized Eruptions Without Fever Many generalized eruptions are not associated with fever Many are fairly easily recognizable, such as psoriasis, contact dermatitis, pityriasis rosea Guttate Psoriasis and Pityriasis Rosea Please see Chapter 70 Rash: Papulosquamous Eruptions and Viral Exanthems for full discussion of papulosquamous skin rashes Rubella Rubella is rarely seen in the postvaccine era in the United States In a classic case of rubella, the rash, similar to measles, begins on the head and spreads caudally The progression occurs over to days, and typically, the rash is entirely gone by the fourth day The rash always remains macular and never becomes confluent, which is an important distinguishing characteristic from measles One-third of all rubella virus infections is clinically silent (i.e., they have no exanthem) The rash of rubella may show extensive variation in location, progression, and duration, at times disappearing within 12 hours or being localized to one part of an extremity without any progression Unlike measles, in which systemic toxicity and fever are the rule, fever is uncommon Associated symptoms and complaints in rubella include joint pain and adenopathy (most commonly suboccipital, postauricular, and cervical) Arthralgia that occurs with a viral exanthem is highly characteristic for rubella Diagnosis is based on clinical presentation, and treatment is supportive Vesicles/Bullae Enterovirus Infections Enterovirus infection can not only cause morbilliform exanthems but can also cause vesicles and blisters The classic exanthem of coxsackievirus A16 infection, also appropriately called hand–foot–mouth disease , is common and easily recognized Infections may occur in epidemics, most commonly in the late summer or early fall Multiple infected members within a household are common Coxsackievirus A16 infection begins with a prodrome of low-grade fever, anorexia, mouth pain, and malaise, followed within to days by an oral enanthem and then shortly thereafter by red macules and papules The oral lesions begin as small red macules, most often located on the palate, uvula, and anterior tonsillar pillar, which evolve into small vesicles that ulcerate and heal over a 1- to 6-day period The exanthem develops into small crescent or football-shaped vesicles on an erythematous base ( Fig 88.14 ) These vesicles, which may be pruritic or mildly tender, are usually located on the dorsal and lateral aspects of fingers, hands, and feet but may develop on the buttocks, arms, legs, and face The lesions improve over to days The other types of coxsackievirus cause similar or even indistinguishable exanthems, which may more commonly involve the face, trunk, and proximal extremities Often, children with these exanthems will be diagnosed with nonspecific viral infections Other symptoms attributed to coxsackie virus infection include aseptic meningitis and less commonly myopericarditis, pleuritis, encephalitis, or paralysis Severe and/or persistent infections may be seen in immunocompromised hosts Diagnosis is usually made clinically, although the virus can be detected by PCR directly from the vesicles or from the stool The virus is commonly shed for weeks from stool Coxsackievirus infections are usually self-limiting, so no specific treatment is necessary IVIG with high antibody titer may be considered for immunocompromised patients or in life-threatening neonatal infections Coxsackie virus also frequently infects eczema prone areas and in this case is called eczema coxsackium (similar to eczema herpeticum) Varicella (Chickenpox) Although varicella is an easily recognizable vesiculobullous eruption, on occasion, the earliest phase can be confusing The initial skin manifestations of varicella virus infection are small, red macules Some of the lesions remain as macules, but most progress to papules and then the characteristic umbilicated, tear-shaped vesicles The earliest lesions appear on the chest and spread centrifugally, but there are many exceptions to the pattern of spread Mucosal lesions can be seen but are usually not a prominent feature Occasionally, a child with mild chickenpox may have only a few scattered macules with only one or two progressing to the more typical vesicular lesions Of children receiving varicella vaccine, 7% to 8% may develop a mild maculopapular or varicelliform rash within month of vaccination Other Bullae/Vesicles Blisters can be related to bug bites, contact allergy, friction, drug reaction, vasculitis, primary genetic disease of the skin, and fluid overload A full discussion of blisters can be found in Chapter 67 Rash: Vesiculobullous Chapter 70 Rash: Papulosquamous Eruptions and Viral Exanthems , covers HSV and Chapter 65 Rash: Atopic/Contact Dermatitis and Photosensitivity , covers eczema herpeticum Localized Eruptions Without Fever Contact dermatitis, insect bites, papular acrodermatitis, and scabies usually present in a localized distribution; however, all may appear as a more generalized eruption in extensive cases Contact Dermatitis Contact dermatitis may be caused either by a primary exposure to an irritant or by an acquired delayed hypersensitivity response to a sensitizing substance A sharp demarcation commonly exists between the involved and uninvolved skin areas Affected skin is erythematous with variable numbers and combinations of macules, papules, vesicles, and/or bullae Diagnosis depends on obtaining a thorough history of exposure and the presence of a characteristic localized pattern of rash Treatment for both types of these dermatitides includes eliminating exposure to offending irritants, providing topical or systemic antipruritic agents, and for more severe cases, providing topical or systemic steroids Please see Chapter 65 Rash: Atopic/Contact Dermatitis and Photosensitivity for additional information Insect Bites Virtually all children experience insect bites Mosquitoes, fleas, and bedbugs are the most common offenders Diagnosis depends on the season, the climate, exposure to animals, and distribution and appearance of the lesions Care is aimed at minimizing discomfort with topical or systemic antihistamines and/or topical steroids Papular Acrodermatitis (Gianotti–Crosti Syndrome) Papular acrodermatitis is an eruption of unclear cause that has been associated with hepatitis B, EBV, and other viral infections in young children, including a similar reaction in the setting of MC In the pediatric population, 85% are younger than years The eruption may follow a low-grade fever or mild upper respiratory symptoms The eruption consists of skin-colored papules that occur anywhere on the body but often concentrate on the extensor surfaces of the arms, legs, and buttock Lesions are particularly prominent over the elbows and knees The rash usually lasts to weeks and then disappears No treatment is needed for the cutaneous eruption; however, a subset of patients with cutaneous lesions develops generalized lymphadenopathy and hepatosplenomegaly These children should be evaluated for hepatitis and follow-up in weeks is recommended for patients with only cutaneous involvement to exclude hepatitis Scabies Scabies is discussed in Chapter 70 Rash: Papulosquamous Eruptions and Viral Exanthems Chronic Eruptions Without Fever Chronic eruptions are defined as those that are usually present for a minimum of weeks Atopic Dermatitis Although the eruption may have a variable appearance (erythema, edema, papules, vesicles, serous discharge, and crusting), its constant feature is pruritus The eruption often has a characteristic distribution, depending on age, and often occurs in allergic (atopic) individuals or those with a family history of allergies (e.g., hay fever, asthma, allergic rhinitis, food allergies, eosinophilic gastroenteritis) Please see full discussion in Chapter 65 Rash: Atopic/Contact Dermatitis and Photosensitivity Tinea Dermatophyte infections usually last longer than weeks A full discussion can be found in Chapter 66 Rash: Bacterial and Fungal Infections/Rash: Maculopapular In short, tinea corporis is characterized by one or more sharply circumscribed scaly patches The center of the circular patch generally clears as the leading edge spreads out The leading edge may be composed of papules, vesicles, or pustules The lesions are most commonly confused with nummular eczema The diagnosis can be made by scraping the active outer rim of papules and examining the scales with a potassium hydroxide (KOH) preparation under the microscope These lesions not fluoresce under the Wood light Treatment with topical antifungal agents such as clotrimazole, miconazole, econazole, terbinafine, and butenafine produces clearing in to 10 days Therapy should be maintained for at least weeks If improvement does not occur, treatment with ... other viral infections in young children, including a similar reaction in the setting of MC In the pediatric population, 85% are younger than years The eruption may follow a low-grade fever or mild