Three times after swimming in three different oceans (Atlantic, Med, Caribbean) I have what I assume were severe allergic reactions: badly swollen feet, lips, and throat, and multiple severe oral ulcers. The first incident led to an emergency referral for suspected Stephens-Johnson syndrome, though this turned out to be incorrect. But it was that severe -- I was unable to swallow for a week, treated with Prednisone. Since then, the next two occurrences were less and less severe, but still debilitating.
Is this a reaction to an algal toxin or something similar? Since the reaction seems to be getting less intense with each exposure, is this an indication of decreasing sensitivity to whatever allergen is the cause? Has anyone heard of anything similar?