petichia rash, have a question

My thirteen year old special needs daughter had a petechial rash on her right arm last week. She did not have a fever, she did have a slight cough that was later on in the week diagnosed as asthma. The rash was on the underside of her forearm and was only at the most ten dots. I noticed it on Wed. evening, it was light pink in color and did not blanch. I have no clue how long it had been there. I took her into the ped. on Thursday morning and he ran a qbc in the office, I think her platelets were 194,000 which are well within range. Her hemoglobin was on the high end of normal and lymphocytes were 32%.Everything was in normal range. By Friday you could hardly see the pink spots and by the weekend they were completely gone. My question is , is there a concern with such a localized incident? I cannot recall her getting hurt or anyhting, the only thing i can think of is she sleeps on her arms. If it were something serious wouldn't more have showed up by now?

[Alan Rockoff, MD]

Doesn't sound serious.  A virus is most likely.  Conceivably, lying on the am might have broken some superficial blood vessels.  Either way, the fact that the spots went away and the platelet count was normal should lay the matter to rest.

Best.

Dr. Rockoff

[MMKK37]

Thanks so much. Would a virus just cause it to be on one arm? Also are there any other light pink spots that don't blanch?Also, would the blood test show signs of somethig even if the petechia had been there for a while and were starting to disappear? And one more thing, does true petchia spread all over and is it darker? Thanks again, Last questions.