Your son probably has dry skin. Your description of his problem suggests that he is either having dry skin eczema or papular urticaria (insect bite reaction). I am sure that you keep your house etc clean..but in a country like India, so far, we haven't really been able to control the mosquito menace. And ONLY 1 mosquito is enough to create severe itching (not in normal individuals like you and me) in boys like yours with dry skin. So a debate on if this is really due to mosquito bite is moot. Make sure that your son wears cotton clothes (full sleeves and pants all the time), and use a little odomos on his skin before he goes out or even when at home. Apply coconut oil 15 min before you give him a bath and bathe him with lukewarm water not hot. Use a mild soap. Also, for the itching you will need prescription medicines so visit an allopathic dermatologist near you. Before you choose your dermatologist read this http://www.skinmatra.com/single-post/2016/07/03/Skin-Troubles-Here-is-WHAT-NOT-TO-DO