Hi and welcome to HCM Given that the rash is periodic, it is more in favour of an allergy. It could be atopic dermatitis, basically allergic causing rashes over the face, in the creases and also other body folds. Did he have similar complaints from a very young age? It could be an allergy which increases with weather changes, dust, exposure to sun, certain plants, animals etc. Also certain foods like nuts, seafood, processed foods,etc. You will need to keep a track of when exactly the rashes come up and if there is a common cause each time. Allergies generally reduce as the child grows, but repeated exposure to the cause can make it recur often. Use a mild sunscreen when outside. When rashes appear , apply a desonide cream on the face for 5- 7 days till rash subsides, not longer. Use an antihistamine like hydroxyzine every night for atleast 10 days during episodes.To confirm you can consult a dermatologist and run tests to check allergy levels in blood, also skin tests for possible causes. Hope this helps.