Cat/Dog Allergy? Jellyish eye!

I have a friend who often finds one of his eyes looking horrible after like one hour at another friends home. This place contains a dog and a cat - but since he minimizes contact with the animals I suspect more factors could be involved then Fel d 1. Anyhow, his eye gets very red and the outer parts of the eyeball slowly transforms, getting that unstable jelly look. I'm sure pet allergy plays a major role here but what supplements do you believe are the best ones helping to avoid getting such heavy histamin reaction?