Ugh! Another Rash???

This 10yo patient presents to your emergency department with a rash and diffuse abdominal pain.  Mom says the child has complained of nausea, vomiting and joint/body aches.  The child is febrile on exam and has the rash in the picture above.

Think for a minute what other questions you would want to ask………

It turns out this child was out hiking several days ago and Mom had to remove a tick when the child returned home.  What are you thinking this may be now?  What would you order to confirm the diagnosis?  How would you treat it?

This rash is a typical rash of Rocky Mountain spotted fever (RMSF.)  There are several things you should remember about RMSF:

  1. In kids, abdominal pain my be a predominant feature.
  2. 10% of pts with RMSF may present with no rash
  3. Principle vector in the Eastern US and South Central US is from the tick Dermacentor variabilis (American dog tick.)
  4. The rash develops between the 3rd and 5th day.  It begins on the ankles and wrists and spreads centrally and to the palms and soles.
  5. Diagnosis is made by sending serology using the indirect fluorescent antibody (IFA) test.  Another name for this may be RMSF titer.
  6. Treatment is with doxycycline 100mg twice a day for three days AFTER the pt is afebrile (usually 3- 7 days.) For kids the risk of teeth staining with doxycycline is minimal with such a short course.  For pregnant women, chloramphenicol can be used. Treatment should be started when the diagnosis is suspected because it may take several days for serology to come back.




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