With cats, your husband is likely reacting to Felis domesticus allergen 1, a water-soluble glycoprotein that cats secrete through their skin, hair and saliva. When they shed bits of skin and hair, the allergens get spread all over the house. Unfortunately, these particles are charged, so they stick easily to the walls and furniture. Of course, most cats hate this, but some get used to it. My preferred treatment for cat allergies and hay fever alike is to use quercetin to reduce allergic responsiveness.
Histamine mediates many allergic responses.
Take 400 milligrams of quercetin twice a day between meals. This is a preventive that will gradually decrease the reactions. This common plant works quickly, with no toxicity. The best form to take for allergies is one or two capsules of the freeze-dried extract every two to four hours as needed. Onions, garlic and hot peppers also help to inhibit inflammation, so use them liberally in meals.