After a few weeks of itching (on the back Mrs, on the back) I finally succumbed to the possibility that what I had might not be simply eczema and popped along to the doctor. My regular doctor (OK, I saw her once a year ago) was not there and I was seen by a delightful young woman not a day over 14 (or am I getting... no can't be that).
I'm always slightly wary when doctors seem interested in your symptoms - makes you feel you are in for a long term relationship until parted by death - but I needn't have worried. I simply have classic symptoms.
Did a patch start itching before the rest of the spots? Yes.
Are they mainly on the upper body? Yes.
Are they in a vague Christmas tree formation? Yes.
Are the secondary patches of itching all smaller than the first? Yes.
Are they oval? Yes.
Are they very itchy and a bit (sorry about this) scaly? Yes.
Bingo. I win pityriasis rosea, possibly a virus and maybe just a something else she said, which begins with a herald patch ('Good news, good news to you I bring, in six weeks time your back will sting') which will clear itself up in 6-8 weeks (that will be this weekend then). HC45 cream twice a day will control the itching.
Knowing what's wrong almost cures you doesn't it? I feel fine now.