[Five cases of erythema infectiosum in adults].
The similarities between clinical features of erythema infectiosum and collagen disease or other viral infections prompted us to investigate clinical manifestations and laboratory data of parvovirus B19 (B19) infection in adults. We diagnosed all five patients as acute B19 infection by antibody assays. The age of patients ranged from 18 to 39 years old (mean 29), and all patients were female. All five patients showed high fever, arthralgia and edema of the extremities. Four of the five patients showed skin rash of the extremities or cheeks. Two patients were diagnosed as erythema infectiosum by family physicians before coming to us. The three remaining patients were suspected to be systemic lupus erythematosus, adult Still disease or rubella indivisually and referred to our hospital. A-27-old female (case 5) visited our hospital because of polyarthralgia and butterfly rash on her face. A test for antinuclear antibodies (ANA) was positive at a dilution of 1:320. Rheumatoid factor (RF) was also detected by latex fixation test. Her AST was 51 IU/L, ALT 68 IU/L and LDH 568 IU/L. Her symptoms persisted for 3 weeks and hepatic dysfunction recovered within 3 weeks. Five months later. ANA was negative at the dilution of less than 1:40. We suggest that the similarities between some symptoms of B19 infection and clinical and serological manifestation of collagen diseases merit closer attention.