r/UlcerativeColitis • u/helloNapartuk • 5h ago
Question UV exposure and UC - experiences?
Hi! Would love to hear everybody’s experiences with getting sunlight and it’s potential effects on the disease.
It is know that uv exposure affects the immune system and might protect from some autoimmune conditions: https://www.scientificamerican.com/article/surprising-ways-that-sunlight-might-heal-autoimmune-diseases/
My recent experience: I had three or four great years of remission while getting uv exposure regularly during the summers. I used to eat lunch outdoors with my colleague during the summer. We would often sit about 20 minutes in mid-day sun, and I was wearing sunblock only on my face, so arms and legs would often get uv. (I live in Finland so even midsummer mid-day sun is pretty moderate.) I also had a garden that I would tend weekly. During this time, I was only on a moderated dose of mesalazine, maybe a short course of local budenoside during the winter. I basically forgot I had the disease.
Then I missed a whole summer (2025) of sunbathing because our office moved and we started having lunch indoors. I also moved and had to give up my garden. And I stopped biking to work. At the same time I got more cautios with uv (to not age my middle-ages skin any further) and was usually wearing spf 50 and clothing when out.
When the autumn 2025 came, I started feeling terribly fatigued at times. At Christmas, a very persistent, steroid refractory flare started and me and docs have been battling that ever since. Now on mercaptopurine since April. It is helping some but also makes me sunlight sensitive so cannot test the potential beneficial effects of uv any more. Biologics (infliximab) are being considered.
Of course it’s hard to say if the decreased uv is the reason for the flare but I’m seeing a pretty clear correlation. I’ve also been wondering if the beneficial effects of smoking for uc actually come from regular sunlight exposure. (Although I know that they have recently discover a bacterial element.)
Does anyone have similar or contrasting experiences?