Common Signs of Dog and Cat Allergies

Allergies are a common problem in dogs and cats. They are among the most common diseases in pets and can cause a number of different types of signs.

Allergies and Skin Disease in Dogs and Cats

By far, the most common signs seen in both dogs and cats with allergies are related to the skin. Unlike in humans where allergies are more likely to cause respiratory signs, canine and feline allergies are more likely to cause inflammation within the skin, known as allergic dermatitis.

Dogs and cats with allergies are likely to become itchy and will begin to scratch excessively. They may bite or chew at their skin in various areas of their body. They may rub against vertical objects or lie down and try to rub themselves on the ground. As the itchiness becomes worse, the skin may begin to become reddened and sore.

The most common signs seen with skin allergies include:

  • hair loss
  • reddened, inflamed skin
  • scabs
  • open sores on the skin

These signs are inflicted by the allergic pet as it attempts to relieve the itchiness by scratching and rubbing.

“Hot spots” are localized areas of inflammation on the skin accompanied by very red skin which may be bleeding and often with hair loss. “Hot spots” are sometimes called “moist dermatitis” and are often the result of allergic dermatitis.

Ear Problems in Allergies of Dogs and Cats

Allergies in dogs and cats frequently involve the ears as well. This is particularly true in dogs. When affected by allergies, the ear canals may simply be inflamed or they become infected with yeast and/or bacteria.

Signs commonly observed with ear problems in dogs and cats with allergies include:

  • scratching at the ears
  • shaking the head
  • an odor from the ears, if infection is present
  • a discharge from the ears, if infection is present
  • hair loss surrounding the ears

Respiratory Signs Associated with Canine and Feline Allergies

Less commonly, canine and feline allergies may cause respiratory signs. These signs may mimic upper respiratory infections in cats and dogs and include:

  • coughing
  • sneezing
  • runny eyes
  • runny nose

Gastrointestinal Problems Associated with Allergies in Dogs and Cats

Dogs and cats can develop food allergies, which may occasionally also cause some gastrointestinal (GI) upset, such as vomiting or diarrhea. The most common cause of food-related allergic reactions in pets is protein.

Though respiratory and GI signs may occasionally be seen in dogs and cats with allergies, the skin and ears are much more commonly affected.