Hi amy,
Sorry to hear that it is an ongoing problem. My fiancee is duel qualified as a nail tec and beauty therapist and she had this a few years back. Her fingers literally swelled up and split like sausages on a grill. It was incredibly painful, she couldn't work, as at its worse she couldn't bear to touch anything with her hands.
Many doctors use the terms eczema and dermatitis interchangeably. In my fiancees case through trial and error we found that she was sensitive to a particular brand of nail product and a brand of spray tan. 2 brand changes later and it is no longer a problem. It still took some time and buckets of moisturiser to calm things down but providing she looks after them her hands are now ok.
Good luck and hope it improves for you,
Gareth