Why Is My Dog Chewing on His Skin & Pulling His Hair Out?

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Dogs chew their skin and pull their hair because they itch or feel discomfort. When a dog experiences itching or irritation, it responds by scratching. If the irritation persists, the dog begins to chew and bite the affected area. In extreme cases, the dog may pull out his hair to gain relief.

The American Veterinary Medical Association lists flea infestation as the most common cause of itching in dogs. Ticks, mites and allergies represent other common causes of skin irritation.


Veterinarians at the Food and Drug Administration warn that a single flea may bite a dog up to 400 times in a single day. A single female flea can lay hundreds of eggs on your dog. With repeated or prolonged exposure, some dogs become hypersensitive to flea saliva and develop flea allergy dermatitis, the most common canine allergy. Although common, flea infestations can lead to serious health consequences, such as anaemia, if not treated.


Dermatologists at the Veterinary Teaching Hospital at Colorado State University advise pet owners to consider allergic reactions as causes of skin irritation in dogs. Unlike humans, canine allergies cause itchy skin more often than runny noses. Canine allergies fall into one of three categories: contact allergies, environmental allergies or food allergies. Contact allergies involve allergens touching the dog's skin. Environmental allergies usually involve the dog inhaling the allergen. Food allergies occur when the dog develops a sensitivity to an ingredient contained in its food.

Ticks and Mites

Tick infestations occur more rarely than flea infestations, but have more serious consequences. Ticks can cause dogs to scratch, bite and chew their skin and can also transmit serious diseases such as Lyme disease and Rocky Mountain Spotted Fever. Sarcoptic and demodectic mange mites and ear mites cause intense itching and irritation to dogs, and each present serious health risks if not treated promptly and effectively.

Other Causes

When other more common causes of skin irritation have been ruled out, a veterinarian must consider an underlying medical condition such as cancer as the cause. Damage to nerve endings from injury or disease, though rare, can cause intense skin discomfort. Dogs that have experienced psychological trauma such as abuse or confinement in small spaces have been known to pull out their hair compulsively. These rare but serious conditions underscore the importance of prompt veterinary attention in cases of severe or chronic skin-chewing or hair-pulling.


If your dog is chewing its skin or pulling its hair, examine its skin closely for evidence of flea infestation. Fleas and their small black droppings are easily visible. In the last few years, many effective options for flea control have become available. Your veterinarian can recommend the best option for treating your dog and its environment. If, on inspection, you find no evidence of flea infestation, it's time for a trip to your vet to determine the cause of Fido's discomfort.