First AD

Second AD

A 5-year-old boy presented with an asymptomatic lacy, reticular rash of 4-days duration. It began with the appearance of a solid red rash on his cheeks. The next day the lacy rash covered his entire body and the solid rash on his cheeks also became lacy.

 Fifth disease

Fifth disease, a dermatosis, gets its name for being the fifth disease with a pink rash to be described after roseola, measles, rubella, and scarlet fever.

Human parvovirus B19, the causative agent, is infectious only in humans.

Fifth disease occurs typically in the late winter and early spring and is typically a disease of early school age. It begins with a prodromal phase of nonspecific symptoms, sometimes a mild fever, malaise, myalgias, and headache. Within a week, reddened "slapped cheeks" appear, followed by the lacy rash to the trunk and extremities. The palms and soles are not involved. This prodromal phase is the contagious phase. When the rash, which may be atypical, appears, the child is no longer contagious. Fever, if any, abates and the child feels better if he had been symptomatic.

Most cases run a very benign course with few or no symptoms, except that the rash may become more prominent when exposed to heat (eg, a hot bath). Parents may become alarmed at the increased intensity of the rash but should be counseled that this is normal and that the color will become less pronounced as the heat dissipates.

Fifth disease is spread by respiratory secretions and is highly contagious. The incubation is from 4 to 14 days but can be as long as 28 days. When one child in the class gets this rash, expect the majority of the class to get it, too. Most adults are immune.

In a non-immune adult, fifth disease can fairly commonly cause an acute self-limited arthritis and, rarely, thrombocytopenic purpura, aseptic meningitis, encephalopathies, peripheral neuropathies, and myocarditis-all extremely uncommon in children.

In children with sickle cell anemia or hereditary spherocytosis, this virus may cause an aplastic crisis beginning with the onset of viremia, usually 6 to 8 days after exposure.

In a non-immune pregnant woman, fifth disease may cause fetal hydrops and stillbirth. No congenital anomalies have been associated.

Chronic anemia may result in non-immune children and adults. Serologic diagnosis is usually unnecessary. Anti-B19 IgM persists for 2 to 3 months. Anti-B19 IgG is detectable a few days after IgM appears and persists for life. Viral DNA will usually be necessary for diagnosis in the immunocompromised patient.

Infection

From lacy and reticular and limited to the cheeks, this rash quickly covered the child’s body and transformed into a solid rash. Your dx?

Vaccine-Preventable Infection?