Hello, I wanted to ask what it could be from. The child has white-red…

Hello, I wanted to ask what it could be from. The child has white-red bumps on their elbows and legs on the outer side. Dry skin. What is it? From what? I read online that there may be many things and also excluded many things (hereditary and so on), but three options remained. 1) Water balance (we don't drink water) in general, just spits out. 2) Under the question - parasites in the body. We do not have pets from where they could come. 3) Climate change. The doctor prescribed ointment. We will go again tomorrow. What do you think it might be?