I'd appreciate some input from anyone with experience with this. When I started going out on the lake every day, doing the muskie assessment, thus being exposed to sun and lake water and fish slime every day, I began to develop a rash on the backs of my hands, mostly the left (and I am left handed). It's like a bunch of raised reddish bumps, not like poison ivy, not itchy but a bit sensitive and warm. It goes away, then comes back when I go out on the lake again.
I'm thinking from the location it's a photosensitivity thing; I had something similar when I was on Doxycycline, an antibiotic for Lyme disease. But it's not on my face, which gets as much exposure as my hands. So maybe if I get my hands wet a bit it might be a combination of lake water and sunlight. I am allergic to one algae that is in this lake; one time I went tubing (towed in an inner tube behind the speedboat) and there was an algae bloom, I broke out in hives, the only time in my life that has happened. But if I am allergic to lake water, that has dire implications for my career!
I even went so far as to check the ingredients in the "natural" hand lotion I may have used the mornings before I went out; perhaps just one ingredient might cause a reaction in me when exposed to sunlight. But of course the label was unspecific when it came to "essential oils".
I should not complain; I know of others who have far worse lots with allergies and general health. But the first time anything happens, you gotta wonder.