My five month old son has petechiae (pinprick sized dots) on his legs, which have come and go over the last month. He is asymptomatic otherwise. Our pediatric dermatologist has guessed the cause is viral , but wants to do a biopsy to rule out serious disease. She said other children in northern NJ were exhibiting similar symptoms, which she had never seen previously in her 20 years of practice. My baby's bloodwork count came back normal for platelets and blood cell counts, but slightly abnormally shaped, possibly indicating a virus. I do not want to do a biopsy unless absolutely essential. Any ideas? I can provide pictures to you.