I stayed at a Hyatt that i was upgraded into one of the allergy friendly rooms (no status they just ran out of standard) It went above and beyond just special request pillows, had one of those specialty air filters. Was great, it was an atrium style hotel, i was the only one that slept because it was a great white noise filter.

If they go above and beyond the normal special request items, i so no reason why they cant treat it as a premium room. It costs time and money to maintain and allergy sufferer isn't a protected class under the ADA so special accommodations are not required (like in the handicapped rooms).