Thanks for the query.
Low platelet can cause these rash
. Platelet can be lowered by any of the following causes.
1. Mild viral infection, like sore throat fever
etc, can cause low platelet.
2. Sometimes the viral infections are very trivial and go off with just mild uneasiness, but platelet are destroyed to a greater level.
3. The next most important cause is intake of medication like pain killer can cause low platelet.
4. Malignancy or disorders of vessel can also cause platelet deficiency
and present as bleed in skin. However in these conditions there will be other symptoms also like high fever
If there are no associated symptoms, you dont need to worry. Just get his platelet levels done.
Wishing him good health.