the fabric.
Cashmere makes the softest sweater due to its natural materials and will feel luxurious to wear against your skin. It will cost you more than most man made fibre products but will last you alot longer.
Some people think so, myself included. I have to wear a thin cotton shirt under my wool sweater.
Pilling - when the fabric from a blanket or sweater makes little pills that sit on the surface.
ugly, wrong size, itchy, already have it
First do you mean, What makes the person itchy when a jellyfish stings you?. Well what i think is that the venom in it.
Allergies
Itchy spots.
if you are itchy you fell it so yeah
It depends on the material used for the sweater.
Fleas
Keep away from sand.