なぜ私の犬は髪を失っているのですか？

Hair loss is a common problem in dogs and can affect your pet’s skin, as well as his endocrine, lymphatic and immune systems. When dealing with alopecia—the technical term for balding—in pets, the most important step is identifying the underlying problem. Then, you can treat it.
 
One of the most common causes of canine hair loss is allergies. Dogs can be allergic to all sorts of substances, from pollen and mold to parasites such as fleas and mites. Your pet may also suffer from a food allergy or nutritional deficiency, which can stress his body and lead to balding. Mange, which is caused by the demodex mite, is a common culprit behind alopecia and can be treated with your veterinarian’s guidance. Because many dogs experience hair loss due to a flea allergy, veterinarians recommend giving Fido a regular flea preventative to keep parasites at bay. Scratching, itching and biting are common symptoms of canine allergies and your veterinarian can run tests to determine which specific allergens are bugging your pet.
 
While common infections and infestations often cause hair loss, balding can also be a symptom of disease in dogs. Cushing's disease occurs when a dog’s body tissues are exposed to high levels of the stress hormone cortisol over a prolonged period of time. Symptoms include hair loss as well as darkened skin and a pot-bellied appearance. Usually a disease found in older dogs, Cushing’s can also effect younger pups that are given too many corticosteroid drugs used to relieve pain and inflammation. Other hormonal disorders that can cause hair loss include Addison’s disease, hypothyroidism, hyperthyroidism, hyperestrogenism in females and hypoandrogenism. Dogs also experience hair loss as a reaction to certain medications, such as chemotherapy drugs or vaccines, and anxious pets are prone to losing their hair as a result of chronic stress. Fungal infections such as ringworm can lead to alopecia that occurs in circular or irregular patches, which also causes infected sores around the rings. Like humans, dogs can get bed sores that cause them to lose their hair, too. These localized injuries often emerge on pets’ elbows, hips and other bony parts, so be sure to provide your pet with plenty of thick, well-padded sleeping surfaces and wrap sores to help them heal.
 
Although hair loss can be a cause for concern, some dogs are simply predisposed to balding. If you’re worried about your pet’s alopecia, visit your veterinarian to discover the underlying cause. While hair loss cannot always be prevented, providing your pet with a clean, low-stress environment and high-quality kibble can help him maintain a healthy coat.