Dry skin and severe hair loss. what causes it even in spring?

Seborrhea: If this is your scalp we are talking about, you have two separate problems. Dryness of the scalp is called seborrheic dermatitis, which is controllable with medicated shampoos & lotions. Seborrhea does not cause hair loss, but lots of other things do. You will need to see a dermatologist and get a good exam & workup to determine the cause.