in my opinion it seems like a simple miliria also called as prickly heat
..but since u said it resolves on applying emosone its an auto immune type disease..most likely an allergic or seborrhic dermatitis
which could happen in this age also.. in my opinion u should consult a dermatologist
for further evaluation..if conditions are auto immune then treatment have to be taken throughout the course of the disease..and relapse or recurrences are common..they have heriditary
preponderance as well.