Cured it with Synthroid for Hypothyroidism
I started having the oozing blisters in Spring of 2010. I eventually tied them to sunlight exposure as it I would spend more than 10 minutes in strong sunlight (spring through fall) and 3-ish days later the blisters would start. Sunscreen would help but only by an extra 20-40 minutes of sun. Another name for what I have seems to be polymorphic light eruption. I fought for years, trying to stay indoors because one episode was enough to set off the blister rash, itch like crazy for a week or so, then slowly dry up, crust up, and bleed as it heals over the next couple of weeks.
Well, after dozens of doctor visits, 4 dermatologists, so many blood tests, and a CT scan of my rash, writing me off as 'these things happen, don't know why' and giving me cortisone cream, I sought out an endocrinologist. He said I have visual signs of hypothyroidism. Then blood tests, and yes, I have hypothyroidism. He put me on synthroid and within a week my blisters went away. Now I didn't go to this endocrinologist to cure a disease I didn't know I had, but the two have to be related because I started taking the meds on April 6th, 2015 and I had no outbreaks despite copious sun exposure, then I stopped taking the meds because I came down with infected tonsils which I naively thought were caused by my synthroid. Well for the 3 weeks I was on antibiotics and that I stopped taking the synthroid, my blisters came back and I fought them every day with cortisone. I then started up the synthroid again and by god the blisters are gone within 2 weeks. Right now all I have is a correlation and not a direct causation, but for the first time in 5 years I do not fear going outside and I haven't had any itchy blisters on my hands for two months now... the longest I have gone itch free in all these years.
All I could suggest is to find an endocrinologist, ask them about dyshidrosis, polymorphic light eruption, and for the love of god just have them test you for hypothyroidism. Don't take no for an answer. Hopefully you will be lucky like me and that will solve your problems. Good luck to all.