What are the causes of your skin to itch after a sunburn?

Sunburn. Inflammation is the cause of itching after sunburn. Histamine is released which causes redness, pain snd itching. Antihistamines and asprin therefore help.
That's normal. As your skin regenerates, the nerve endings which were damaged are now making new connections to the new collagen in the skin and the itching which occurs is a normal symptom of this . A short course of an antihistamine or cool packs can diminish the itching which occurs over those 2-3days.