Expression of this glycosphingolipid in tissues helps to determine parvovirus B19 tropism. The rash of erythema infectiosum usually appears without prodromal symptoms after an incubation period of 4 to 14 days. The exanthem progresses through three stages. One to 4 days later, an erythematous maculopapular eruption appears on the proximal extremities and spreads to the trunk in a lacelike, reticular pattern. The third stage, during which the eruption waxes and wanes, may persist for several weeks and may be precipitated by skin trauma, exposure to sunlight, or extremes of temperature.
Joint involvement is often symmetrical in the hands, wrists, knees, and ankles.
Hemolytic anemias and encephalopathies are rare complications. Transient aplastic crises associated with parvovirus B19 occur in patients who have sickle cell anemia, hereditary spherocytosis, thalassemia, and various other hemolytic anemias. These aplastic crises are abrupt in onset and associated with giant pronormoblasts in the bone marrow. They generally last 1 to 2 weeks and go into remission spontaneously. Severe pneumonia after organ transplantation has also been reported.