Turns out it wasn't. Looked a lot like a toxic reaction of some sort. Three weeks later with pseudotumor cerebri. Had two taps and was on diamox for several weeks. Bone marrow was normal.
All antibody tests are normal.
We're seeing a ped rheum in a few weeks. As you can see there is an extensive list of possible underlying disorders, the rigour with which one would investigate each one depends on the clinical picture. All rights reserved.