Thanks for writing to us.
from the description it seems either he could be having fungal infection
known as tinea or eczema
. The treatment in both these conditions vary. Tinea requires antifungal treatment while eczema requires steroid
creams and emollients.
It is better to consult a qualified dermatologist
to get the diagnosis confirmed and treatment be started. It does not seem to be related to his previous episode of ITP.
Hope that helped.