Fleas may not be as life-threatening as ticks, but they can pose a serious health concern to your pet if it's allergic to them.
Fleas are the most common source of allergies in dogs and cats. The fleas' saliva triggers the allergic reaction in dogs, not their bodies. The American Society for the Prevention of Cruelty to Animals (ASPCA) estimates that one out of every five dogs in the United States has an allergy of some kind [source: Bogue].
Some pets get the same symptoms we associate with allergies in people -- sneezing, wheezing and goopy eyes. More often, though, the allergy is evident on skin. If your pet falls into an itching and scratching fit that doesn't abate, it's probably allergic dermatitis [source: Bren].
Aside from fleas, there are four categories of pet allergens:
Any or all of these allergens may be present in travel situations. A new location will expose your pet to many new plants, grasses, insects and other organisms in the environment. Even the most pet-friendly hotel or apartment complex may have a carpet cleaned with a solvent that rubs your pet the wrong way.
In some locations, it can be difficult to maintain your pet's usual diet. An animal can even react to the water in a new place, leading to vomiting or diarrhea -- which can also be an extreme allergic reaction [source: Bren]. Packing foods familiar to your pet would prevent this.
Pet allergies can take you by surprise, and it is often difficult to prevent exposure. Symptoms may not present themselves until after you've returned from a trip. If you're aware of your pet's allergies, you can make efforts to limit exposure, such as limiting your pet's time outdoors during pollen season.
For a range of treatment possibilities, continue reading.