EI, also known as “fifth disease” or “slapped-cheek disease,” is a common viral illness that appears sporadically or in epidemics. It typically presents in children aged 4-11 during the winter and spring months. In adults, the infection almost always goes unrecognized.
The classic presentation of EI is a bright, erythematous rash that appears on the cheeks and forehead but spares the nasolabial fold and perioral area (as though the patient had been slapped on the cheeks). The rash fades after four days. A red lacy or fishnetlike rash on the torso and extremities often follows resolution of the facial rash. Sun exposure, bathing, and exercise are known to exacerbate the appearance of the rash. Pruritus may also be present. Concurrent arthralgias and GI complaints are more often seen in adults than in children. Knee, hand, and ankle joints are typically affected, and pain is often symmetrical. Joint pain is not found in men. In adult women, arthralgias may last from two weeks to four years.
More serious complications of EI include thrombocytopenia and neutropenia. Transient aplastic crisis can occur in patients with chronic hemolysis. Bone marrow failure may be seen in immunocompromised patients.
Expectant mothers are at risk for fetal infection. A pregnant woman with a new rash or arthralgia should be tested for EI. Most commonly, pregnant women have asymptomatic seroconversion. Fetal demise is a possibility due to severe anemia or fetal hydrops. Greatest during the first trimester at <9%, the risk of fetal demise drops in succeeding months. Congenital abnormalities have not been reported in live births to mothers with EI.
Generally, diagnosis is made following a thorough examination and history, including presenting symptoms. Testing is rarely required. Blood tests should be performed on pregnant or immunocompromised patients with suspected disease. A serum B19-specific IgM antibody will confirm recent infection. Serum IgG antibody will confirm past infection and immunity.
Treatment typically is not required for patients with EI. The illness is self-limiting, and the rash usually resolves within a few weeks. Clinicians should reassure the patient that the rash is temporary and does not require treatment. Immunocompromised, anemic, and pregnant patients should be referred to the appropriate specialists.
Because EI is so common, preventing exposure is often impossible. It is recommended that infected children not be excluded from school because transmission occurs prior to symptom onset.
Mrs. R’s fevers and rash subsided about four weeks after they first appeared. Her joint pain, however, persisted for approximately six weeks. The hydrocodone and acetaminophen allowed her to continue with her normal daily routine.
Mrs. R provides a perfect example of how a very common disease can present in an unlikely patient population and with atypical symptoms. Hers was the first case of adult EI that had ever been seen in our clinic.