As I have discussed in the past, the most common reason pets are itchy are from environmental allergens: pollen and airborne molds. So, I get a lot of questions this time of year about why clients’ cats and dogs are itchy when none of this stuff is flying around during cold weather. The answer is still usually allergies, but they are the so-called “winter allergies”. As with human allergies to the outdoor culprits, the winter allergies are the same across all three species.
Dust Mites: This is the most common indoor allergy. Dust mites feed off of microscopic dead skin and love warm, humid environments with a tendency towards mattresses and cushions. Despite this, in New England, they seem to be at their worst during the coldest months when the air is at its driest. There are many theories as to why this may be the case, but the two most plausible are that 1) The heating systems (regardless of whether they are baseboard or forced air) are tending to kick up more settled dust when they are on regularly and 2) Our skin is at its driest during this time of year providing more food for the mites (gross…).
Indoor molds: While warmer, wetter climates get the terrible black molds that can cause respiratory issues, we see this very little in the Northeast. That said, we do have household molds that will grow when the air is moist. Being near the ocean with lots of fog at dawn and dusk, homes around here will get this the worst. The airborne mold particles are not as bad when it is moist, but the growing mold will produce more spores when the air begins to dry out. These spores and particles of dead mold are then flung around the home by our heating systems the same way as dust mite particles.
Pet Dander: Yes, your dog can be allergic to your cat and vice versa. It’s not seen terribly often, but it can happen. Much like our own dry skin can worsen dust mites, pets’ dry skin can worsen direct allergies to patients that are sensitive.
Outdoor allergens inside: If your dog has a pine allergy, bringing a Christmas tree into your home can be a nightmare for them. It is often overlooked as it only lasts about a month, but it’s something to be aware-of.
Food: Ok, so this isn’t really a “winter allergen”, but it’s on our list of things to rule out when a pet is itchy in the absence of outdoor allergens. Much like people with systemic responses to food allergies, pets can become itchy when ingesting certain ingredients. While the veterinary dermatology community seems to go back and forth about how common these allergies are, most seem to think only about 10% of itchy skin issues in pets are caused by food.
So how do we cope with this? In the case of food allergy, it’s a matter of ruling out environmental allergies with testing or response to treatment. Then we can start hypoallergenic diets. For the airborne allergens, pets will respond just as well to allergy medications as with outdoor allergens. That said, this may not be necessary with some changes to the environment. Vacuuming the heating system and changing filters regularly is the first step. If the itchiness continues, we’ve had amazing success with people adding air filters. One side effect of the COVID panic was an overproduction of air filters, so they’re pretty inexpensive these days. There’s no reason for any fancy UV filters, just something with high air flow and a good HEPA filter. We have gotten many pets off of medications simply by adding one of these units to the home.