Just a quick one. I've been in touch with Amersham Hospital again, and they've confirmed which fragrance I'm allergic to. Turns out to be isoeugenol. It's used in lots of household products like shampoos, detergents and fabric conditioners, so is going to be a bugger to avoid in life. The big problem is that it's rarely identified by name. As a rule, fragrances get lumped together and labelled as parfum or fragrance.

Amusingly, because these chemicals occur in nature, it's not even reliable to stick to botanicals or "all natural" products. Apparently, even some "unscented" products still use these fragrances in small quantities to mask unwanted chemical odours.

The difficulty with avoiding them is that the reaction is delayed. I've had a couple of people thinking it was like an anaphylactic reaction to bee stings or peanuts - basically instant. But no, it's delayed after exposure, which makes it much harder to identify what actually caused the reaction. Apparently it's a type 4 hypersensitivity, so there.

In other news, Ros's mum is home from hospital after a hip replacement on Wednesday. I've just a chat with Val on the phone and she sounds very cheerful, which makes us all very pleased.