I just saw a rash this morning while teaching medical residents.  Have you heard of “fifths disease?”  I saw a slap-cheeked looking kid, at little risk of being abused.  The offending virus is Parvovirus B19.  Interesting questions were brought up.  The mom of this patient  is pregnant.  So, that unleashes a “can of worms.” 

There are significant risk factors for that mother as parvovirus can cause fetal death (rare, but possible).  We will follow blood work on the mother (parvovirus IgM and IgG) to see if she has been exposed to this virus before or if this is a “new-sighting” and therefore is more dangerous to the fetus.

For the most part, no rash (or viral) treatment needed.  The slapped-cheek look resolves spontaneously.  Some have joint pain  or mild fever both symptoms can be treated with non-steroidal anti-inflammatory pills (like ibuprofen).

For patients with sickle-cell disease or autoimmune diseases, parvovirus can cause severe blood breakdown, requiring transfusions.

We are unsure of the mode of transmission (saliva?  fomite?).  We know that parvovirus passes through a household fast, but may make its way through a school over several months.  Advice: Avoid contact with sick people.  Cover your cough.  Wash your hands!

Hope this helps.