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:
- In kids, abdominal pain my be a predominant feature.
- 10% of pts with RMSF may present with no rash
- Principle vector in the Eastern US and South Central US is from the tick Dermacentor variabilis (American dog tick.)
- 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.
- Diagnosis is made by sending serology using the indirect fluorescent antibody (IFA) test. Another name for this may be RMSF titer.
- 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.