This will sadly not be as good as the rat thread, but as the collective mind of TTH helped solve that one I thought I'd put you all to work here.

So my house is making me ill, or to be more precise, causing me to break out in hives/welts/itchy as fuck things on my arms/shoulders, legs and sides.

I've had this for about three months now on and off and after ruling out actual diseases/fad allergies one by one some extended time away from home due to work made me realise there's something within these four walls that's poisoning me. I originally thought last week that it was dust mites, so out went the old upholstery and the place was cleaned from top to bottom (including carpets being steam cleaned), but 5 days on from that and it's still happening with a fresh round of the above on my right shoulder and left arm today.

Some more googling suggests it might be mould, but I can neither see nor smell any signs of the stuff so I'm reaching the point of being genuinely stumped by this and it's making just living life a right pain in the arse, or an itch in the arm/leg/shoulder if you will.

So... any ideas?