What mononucleosis is Infectious mononucleosis is a clinical syndrome most commonly linked to Epstein-Barr virus, or EBV, a member of the herpesvirus family. EBV is very common worldwide, and many people are infected at some point in childhood, adolescence, or…

What roseola is and why the fever-rash pattern matters Roseola, also called roseola infantum or exanthem subitum, is a common viral illness of early childhood. It is most often linked to human herpesvirus 6, and less commonly human herpesvirus 7.…

What fifth disease is Fifth disease, also called erythema infectiosum, is a common viral exanthem of childhood caused by parvovirus B19. The name “fifth disease” comes from an older classification of childhood rash illnesses, where it was listed after measles,…

What scarlet fever is Scarlet fever is an infectious illness most often associated with group A Streptococcus, the same bacterium that can cause streptococcal pharyngitis. In scarlet fever, certain strains produce toxins that trigger a characteristic rash alongside symptoms of…

What chickenpox is and why it spreads so easily Chickenpox is a primary infection with varicella-zoster virus, a member of the herpesvirus family. After exposure, the virus replicates in the upper respiratory tract and lymphoid tissue before spreading through the…

Why flu and colds are easy to confuse Influenza and the common cold are both contagious respiratory viral illnesses, and in children they often overlap: cough, sore throat, nasal congestion, reduced appetite, and disrupted sleep can occur with either. Both…

What hand, foot, and mouth disease is Hand, foot, and mouth disease is a contagious viral syndrome, not the same as foot-and-mouth disease in animals. In children, it is most often caused by non-polio enteroviruses, especially coxsackievirus A16, coxsackievirus A6,…

What RSV is and why it matters in childhood RSV is an enveloped RNA virus that infects the respiratory epithelium, meaning the cells lining the nose, throat, airways, and lungs. Nearly all children encounter RSV early in life, and reinfection…

What croup is and why it sounds so distinctive Croup is a common childhood respiratory illness in which inflammation and swelling develop in the upper airway, particularly around the larynx, vocal cords, and trachea. Because young children have relatively narrow…

Why coughing often sounds worse at night Cough is a protective reflex designed to clear mucus, irritants, or secretions from the airway. At night, several normal physiologic changes can make a child’s cough more noticeable. When a child lies flat,…