hi from this description it seems to allergic dermatitis
due to grass .you got sensitised to it when you were younger. now on rexposure to the grass they appeared again
it doesnot seem to be scabies
as it is aquired from an infected person or bed and linen of that person
other itchy spots appear when you itch indicate that this may be urtidaria which may be due to prior sensitisation .
any type of itch decreases with cold
and decreases with heat exposure so itching increases during steam bath
Short course of oral steroids
is advised after doctor consultation.
scabies cant be ruled out so examination by doc is advised