Hi Mary
Sorry to hear about your son - ITP is such a nuisance, and for us parents, so easy to panic about too!
A bit of history. My 10 (now 11) year old son was diagnosed in May last year. He had a count of 5K, stayed overnight in hospital, and went home with a count of 8K. His count hovered around the 10K mark for the next 6 months, sometimes getting into the teens, sometimes going down to 1K. He missed a bit of school due to appointments, but only 1 day because of his count. Most of the time he also continued to play sports, albeit a bit more carefully. Since November last year, his count has improved and now bounces around all over the place (15K to 124K). Mostly it seems to be around 30K.
In the UK it is very uncommon for children to be treated for low counts unless they are accompanied by significant bleeding - I mean something more than bruising or petechiae. My son did have a couple of weeks of prednisolone when the doctor at the local hospital thought he was having problems, but I wouldn't do this again based on the symptoms he had then. The side effects of most of the drugs used to improve platelet counts can be very significant.
I am a great fan of wait and see as an approach. Although the symptoms of ITP can be scary to look at, they are mostly just cosmetic. They are probably not going to do your son any long term harm. I don't think that treating ITP makes it get better quicker, or less likely to become chronic. I've never seen anything to suggest this. I do know however that not treating it hasn't done my son any harm. You need to be very aware of his symptoms and what to watch out for - as you have already found, petechiae are a good indicator. And you also need to be happy with this as an approach - if you can't live with it without worrying too much, you need to tell the doctor this.
As to when you might expect improvement: I think that my son's doctor says that 3/4 of kids are improving within 6 weeks, about 80% improve by 6 months, and about 90% are better within 12 months. Annoying as it is, the answer to your question is going to be "I don't know". How long is a piece of string? Older children are a bit more likely to have the chronic form apparently. It gets easier to deal with I think. I was talking to my mum last night, and she was asking how Dougie was - I said that he was having less problems with ITP than my niece does with asthma, which I think puts it nicely into context. I do think that Dougie is very lucky not to have many symptoms though.
I hope that your little boy improves soon anyway. This is a great place to come to for information and support - just talking things over with other parents solves a lot of worries I find.
Ali