Hello doctor, I recently experienced a petechiae rash on my legs and arms and easy bruising. My PCP ordered blood work to look at platelet levels. The only abnormality was a slightly prolonged aPTT time (40 seconds and the lab reference range is 25 to 36 seconds). Further blood work was done: Von Willebrand factor activity, factor VIII activity, and factor VIII related antigen, all of which were borderline low but still within the lab reference ranges. My PCP said there was no evidence of Von Willebrand deficiency and that the petechiae were likely caused by straining while weight lifting. However, I have weigh lifted for many years and never experienced petechiae until a couple of months ago. So, I am wondering if there are any other lab tests that I should ask to be done or if there is no need to do further testing.
Hello. For the petechial rash, you need to investigate with full CBC to check platelet count. Low platelet count is one of the causes of such a rash. I suggest you investigate with SGPT and ultrasonography abdomen to check for liver disease.  Your raised APTT is a surprising result and points towards some coagulation deficiency (attachment removed to protect patient identity). So I suggest you investigate with mixing the study of APTT investigation which will guide us further for detailed workup. If mixing study report is suggestive of an antiphospholipid syndrome-like presentation than you can investigate further with anticardiolipin antibody estimation. So, this is something you can discuss with your treating doctor regarding mixing study for APTT. Meanwhile, over the bruise you can apply Vitamin K cream. I suggest you take Vitamin C lozenges for a few days which will help in managing rash. You can revert back once CBC and USG reports are done.