Fifth Disease. Parvo b19 virus causes upper respiratory symtpoms and low grade fever which resolve promptly, to be followed by a facial rash with a "slapped cheek" appearance. The remainder of the body soon develops rashes, sparing the palms and soles. The rash will soon show central clearing, which has a "lacy, fishnet" appearance. The illness is mild and self-limited, and the rash waxes & wanes. No treatment.