Viral Exanthems in Children: Measles to Hand-Foot-Mouth

Overview / Definition Viral exanthems are generalized skin rashes that occur in response to viral infections, predominantly in children. They typically present as maculopapular or vesicular lesions and are associated with systemic symptoms such as fever and malaise. Key viral exanthems include measles, rubella, varicella, and hand-foot-mouth disease. Epidemiology Viral exanthems are prevalent in pediatric populations, particularly in children under the age of five. The incidence of these infections varies based on vaccination rates and geographic location. For example, measles has seen a resurgence in areas with lower vaccination coverage. Measles: Most common in unvaccinated populations Hand-foot-mouth disease: Higher incidence in children under five, especially in daycare settings Varicella: Peaked incidence in late winter and early spring Pathophysiology / Mechanism The pathophysiology of viral exanthems involves the entry of viruses into the body, often through the respiratory tract, followed by viremia and subsequent skin involvement. Each virus has a unique mechanism of pathogenesis: Measles virus: Causes a systemic infection with a characteristic rash due to immune-mediated damage. Rubella virus: Induces a mild illness with a rash resulting from viral replication in the skin. Enteroviruses (e.g., Coxsackievirus): Lead to localized lesions in the mouth and extremities due to direct viral invasion. Clinical Presentation The clinical presentation of viral exanthems varies by the causative virus, but common features include: Measles: High fever, cough, coryza, conjunctivitis, followed by a maculopapular rash that spreads from the face to the body. Rubella: Mild fever, lymphadenopathy, and a pink rash that starts on the face and spreads downward. Varicella (Chickenpox): Fever, malaise, followed by a pruritic vesicular rash that progresses from macules to vesicles. Hand-foot-mouth disease: Fever, oral ulcers, followed by vesicular eruptions on the hands, feet, and