If you've ever been kept awake by a dog that can't stop scratching, biting and licking itself, then both of you have suffered from skin allergies. Skin allergies, or dermatitis, are one of the trickiest problems to diagnose in an animal, since they can have many different causes. In its misery, the affected animal also usually worsens the problem by continually scratching and licking at the affected places, undoing any healing that's occurred.
There are six categories of dermatitis: allergic, environmental, infectious, neurogenic, nutritional and parasitic. Anything from food, carpeting, blankets, dust mites and mold spores in the air to pollen, plastic food dishes, furniture stuffing and ornamental plants all can trigger an allergic reaction in dogs. Food allergies, especially, are commonplace. So common, in fact, that many pet food manufacturers now produce "antigen specific" diets to help treat dogs with food allergies.
Infectious dermatitis is caused by bacteria, fungi or yeast organisms, and results in moist, sticky and inflamed skin lesions, combined with hair loss. The bacteria spread rapidly and can be transferred to other areas of the skin through licking and scratching. One specific type of bacterium, Microsporum canis, causes the well-known circular type of hair loss known as ringworm.
Treatment for infectious dermatitis starts with clipping the fur away from the infected site to help air dry the skin. Topical medications also are applied, and oral antibiotics are prescribed to fight the underlying bacteria. Antihistamines and cortisone also may be given to suppress the itching. The use of the latter, however, is at the veterinarian's discretion, since cortisone can slow the healing process.
A second type of dermatitis is caused by factors in the environment, such as exposure to swimming pool chemicals, soil or even some types of grass. Nutritional dermatitis, meanwhile, occurs when the dog is receiving inadequate nutrition. It's a common condition among pets that are fed the cheapest brands of dog food, which usually don't live up to their "complete and balanced diet" claims. If you feed your dog exclusively dry food, make sure the first ingredient listed is meat, such as beef, poultry, lamb or fish. Omega-3 fatty acid supplements also help many dogs recover from this type of skin allergy.
Allergic dermatitis, meanwhile, can be triggered by a wide range of allergens, including food ingredients, synthetic and natural fibers, medications, over-the-counter pharmaceutical products, plants and even dust and dust mites. In some cases, the dog's own naturally occurring bacteria can spark an autoimmune response, resulting in dermatitis. Just as with humans, a dog's specific allergies can be diagnosed through blood and skin tests.