Hi Beccy, thanks for your interest in my post, sounds like you are going through a horrific time of it not only in the pain and discomfort but also the treatment and pills they are stuffing into you!! I think that, whilst your doctors comment does not seem helpful, i.e. they may never identify the cause, this is sadly the truth and the most frustrating thing about Chronic 'Ideopathic' Urticaria. They have not a clue what is causing it so to stuff you full of meds/treatments is only treating the symptoms and not the cause. Identifying the 'cause' is your only hope to ending this terrible condition.
I lived with this awful condition for around 18 months and like you sometimes there was no rhyme nor reason behind the outbreaks, they were always there lurking in the background, just waiting for something to trigger them. Having explored many forums and internet research in the quest for answers I stumbled upon the mirena as a possible cause. I toyed with the idea for a good few months, did more and more reading. Excluding factors like stress, job and house move (and actually testing these out to a degree by changing environments!) I eventually came to the conclusion that the mirena was the only change in my life which could be a credible cause. When I went to the clinic for removal (April 2016) they practically scoffed at me - especially when I mentioned internet forums! The nurse said 'well I've never been asked to remove one because of that' I showed her a photo of a flare up and said 'if I'm wrong then this won't clear up and I will come back for another one, but I have to try to see for my own health if I'm right'.
As per my post there was an instant improvement and this has continued over the 10 months since but it has been slow and not 100%. Throughout this time I have had a few isolated hives, really just one or two, strangely way more itchy than the full body rash but piriton has dealt with them easy and in general I would say, yes I was recovered (almost!). Then, in Jan 2017 I attempted to deal with my insomnia (mostly technology related but bad habits continue!) For about 8 days I took Nytol and guess what the bloody hives came back and with a vengence too! My heart sank! They mostly appeared after any activity - walking, running, housework even the weekly shop at Tesco! I went back to the gp and he gave me citirizine 10mg (which I never really tried the first time round) so I took one in the morning and piriton 4mg at night. Did this for a few weeks and sure enough the hives have gone again. In fact since last week I have not had ANY at all - even after activity. Have they finally burnt themselves out? I hope so!! Perhaps it was a relapse, perhaps it was a sign that my immune system is still compromised, who knows?
Well, I suppose the crux of my reply is that the start of the end was definitely removing the mirena, it certainly played havoc with my immune system and this has taken almost a year to recover fully - and even then I'm still scared they will come back!!
Have the coil removed and give your body time to fully recover, it really is worth trying and if it is not that then you can always have another one and continue with your search for possible cause.
Hope this has helped a little, I really feel for you, and I wish you luck in your recovery. Gina x