My son is on trimethoprim daily.. started on 0.6ml from when he was born.. and now at 1.2ml. he had a lumber puncture procedure - he came out with unexplained bruising:red marks o his forehead ( 5 finger print marks ) do you think the trimethoprim could

No other bruises?: If there are no other bruises nor little blood spots to suggest a problem of bruising-easily or bleeding-easily, and if a child just came back from an lumbar puncture, one possible explanation is that the clinicians had to hold a child tightly in order to safely do a lumbar puncture; which can explain fingerprints or handprints. They don't want a little kid to move at all during a lumbar puncture.