I started to have an allergy attack yesterday from cross-contamination with wheat, based on the symptoms (immediate asthma, blurred vision). I thought I'd be unable to work for hours, but I took a charcoal tab and within twenty minutes I was at the keyboard again. I didn't even need an allergy pill, though I had one handy just in case. If it had been a milk allergy, I'm not sure if I'd risk it because I go into shock and my throat swells, plus the charcoal might absorb and negate the allergy medicine.
That said, I've headed off milk allergy with coffee (caffeine saves lives) and an allergy pill, so I might test it some day...with an epipen and coffee close at hand, of course. I'm not a fool.