R.J.
You know... my son has no allergy to milk whatsoever... but his skin gets blotchy (and always has) if he spills either milk or juice or soda or coffee (iced) on his skin. Kind of red and lacy. Then it goes away in as little as a few minutes to as much as a few hours. I've always sort of thought it was the sugars... because he also gets red "drip streaks" when he eats juicy fruits.
Not ALL the time... but whenever it sits on his skin and warms (like in the car, or summertime, or I just don't notice and he doesn't wash up himself. As a baby, his own drool would soak in his onsie and he'd get red marks where it had been wet.
His skin isn't super sensitive to ANYTHING else (not detergent, sun, chlorine, saltwater, none of the common irritatns)... but anything with sugars in it, he splotches out.
He's also hypoglycemic. No idea if that ties in. Now I'm puzzled... I just taught him to wipe himself (and myself to pay attention)... so I've never really paid much attention to it. I wonder if it's a hypoglycemia thing... I'd always just sort of assumed it was a yeast thing. ((He's prone to yeast infections, and sugar + yeast = oy vey))