Good question, bcz it makes me itch like a MOFO! Funny thing is, it's always been that way even as a toddler...my mom would put wool hats on me & I would be itching...& irritated til I took it off. Same with sweaters...just an irritating reaction to wool. What I found helped was to make sure the wool was over a lining...that way it didnt hv direct contact with the skin...then all is a ok. ;)
Most people think its an allergic reaction, when its not. It causes the scratchy itch feeling because the wool rubs against the skin. The wool has a very scratchy feeling and when rubbing it up against your skin creates an "itchy" sensation.