Bacterial and viral infections are frequently associated with fever and rash in children. Many of these rashes have known etiologies and characteristic features. Recognizing the clinical features of the rash and identifying key points in the history can help with diagnosis. In the Table 26-1, key points in a number of pediatric exanthems are summarized, as well as other rashes associated with fever. Most exanthems are self-limited and require only symptomatic treatment. Hypersensitivity reactions, such as those due to viruses or medications, can also present with fever and maculopapular rash. Vaccinations have significantly decreased the incidence of measles, rubella, varicella, and their congenital complications. However, isolated outbreaks of imported measles still occur, especially in unvaccinated populations.1,2 COVID-19 has emerged as a novel cause of fever and rash in children and adults.3 With travel to endemic areas, infections such as Zika and West Nile virus should be considered. Tick-borne infections such as Rocky Mountain spotted fever and Ehrlichiosis require identification and treatment.
Table 26-1.Diseases associated with fever and rash. ||Download (.pdf) Table 26-1. Diseases associated with fever and rash.
|Disease/Etiology ||History ||Clinical signs ||Laboratory evaluation |
(Rubeola; 1st disease)
|Incubation: 8–14 days. Prodrome: Fever, cough, coryza, conjunctivitis. Rash lasts 4–7 days. ||Erythematous macules and papules appear on scalp along hairline and behind ears. Spreads in cephalocaudad distribution (Figure 26-1) and by 5th day, clears in same direction. Koplik spots (red macules with a white blue center) may be seen on the buccal mucosa. Complications: Otitis, pneumonitis, encephalitis, myocarditis. ||Fourfold increase in acute and convalescent titers confirm diagnosis. PCR and ELISA are also available. |
Varicella zoster virus
Incubation: 10–21 days
Prodrome: Malaise and low grade fever.
Late fall, winter, spring.
|Tear drop vesicles, "dew on a rose petal" (Figures 26-2 A and B). Multiple lesional stages present at once. Immunocompromised patients at increased risk of disseminated disease, pneumonia, and secondary infection. Reye syndrome associated with aspirin use. Congenital varicella is associated with hypoplastic limbs. ||Clinical diagnosis usually sufficient. PCR, DFA are available for rapid diagnosis, viral cultures take several days. Acute and convalescent IgM and IgG antibody titers confirmatory. |
|Post-natal infection in immune competent usually asymptomatic, but mononucleosis like syndrome may occur. ||Erythematous macules and papules in diffuse distribution. Skin or mucosal ulcerations are possible. Complications include congenital CMV: 'Blueberry muffin' baby resulting in hearing loss, seizures, intracranial calcifications. ||Urine virus isolation, serologic evaluation, antigen (blood), PCR analysis (blood). Skin biopsy may show intracytoplasmic, intranuclear viral inclusions in endothelial cells. |
Human Herpesvirus 4 (HHV-4)
Incubation: 30–50 days.
Prodrome: Fever, pharyngitis, lymphadenopathy, malaise, anorexia. Rash following use of amoxicillin/ampicillin.
|Morbilliform rash spreads over entire body (Figure 26-3A). Periorbital edema. Petechiae on palate (...|