When I was a child I often got 'a smell in my nose' as I used to describe it to my Mum. I knew it wasn't outside, coming from anywhere, it was inside my nose. And it smelled like Arrowroot biscuits. That's the only way I could describe it. I always got this smell before coming down with something like measles or chickenpox or a bad chest infection. I would also lose my appetite until the smell had disappeared.