My DS reacts severely to dogs - hives, swelling, coughing, wheezing. HE doesn't even have to touch them, just be in the house where they are. I think it was Rebekah who mentioned sleek coated cats being worse - when DS first started reacting to dogs, it was the short, oily-coated ones that got him the worst. Boxers, labs, beagles, etc. Eventually, it became all dogs, but his two worst reactions were to a poodle and a Yorkie. Go figure.
SL, your DS is on to something with his "color coding", but he's slightly off base. There is a link between color and allergen shedding. According to recent research, light cats are less allergenic than dark, female less than male.
I used to have a pair of female cats, Oreo and Inca. Oreo was white with black splotches, Inca jet black. I was really not a particularly fussy housekeeper in those days, and nobody realized I had a cat until they strolled out to greet their adoring public. People who swore they had horrible cat allergies never even sniffled around them.
Little Foot, an orange male, was an allergy
bomb. Even I would react with a slight cough at times when nuzzling him; that's when I knew it was time for him to have a bath - which really helped.
I feel for your DS. My DS had to stop going to certain houses, among them was one of his best buddies from birth. But now that he's on the other side of puberty, I'm seeing some hopeful signs. He can tolerate one friend's dog - a beagle, of all things. Yes, he has to wash his hands if he touches her, but he
can touch her. And be near her. And be in the house with no problems. I'm hoping his doggie horizons will continue to expand.