Can't help you on the cat allergy side of things Kel, but i had allergy testing done for my ecezma at a place in the city (just near St Vs Private).

It's more intensive than scratch testing, but it doesn't get to the root of all your problems. I had 130 disks placed on my back on the monday, went back on the wed to check them, and on the Friday they were removed.

They get you to bring in all your products (makeup and skin products), and they make them up on disks to check you for them (you can develop allergies over time.. and loose them over time also).

You need a referral from a GP or dermo.. But if you want the name of the place and a good dermo to see also, let me know (trust me, i've seen enough of them!).

In terms on washing powder, the only one i have found that i good for my skin in Omo Matic (for front loaders) Sensitive, or Omo Sensitive. The other sensitive brands weren't as good. Also make sure your fabric softner is an sensitive ones, as lots contain stuff to irritate skin also.

HTH.