Dog Diseases & the Hair

A dog's coat of hair grows in a constant cycle of renewal. When a dog is healthy, his hair should be thick and shiny. Some diseases, such as parasitic infection or endocrine disorders, cause hair loss and coat thinning.

  1. Dog Disease

    • Dog diseases that cause problems with a dog's hair include fungal infections such as ringworm and mite infections that cause mange. Cushing's disease is an endocrine disorder that causes hair loss all over a dog's body. If your dog has an internal parasite causing nutritional deficiencies, he could experience a thinning coat, according to the book "What Your Dog Is Trying to Tell You."

    Symptoms

    • Ringworm causes hair loss in round circular patches, often on a dog's head and ears. Mange can cause bald patches on your dog's head and neck, resulting in a coat that looks moth-eaten. Cushing's disease causes hair loss all over a dog's body, sometimes leaving him bald except for the head and legs. If your dog's coat is thinning and the hair that remains looks dull, it could be the result of an internal parasite.

    Causes

    • According to the ASPCA, ringworm is caused by a contagious fungus. The skin lesions it creates result in hair loss. The mites that cause mange can concentrate in one area, burrowing into your dog's skin and hair follicles, causing balding spots. Cushing's disease can be triggered by a tumor growing on your dog's adrenal glands. The tumor can cause an overproduction of the hormone cortisol. An internal parasite can steal enough nutrients from your dog's system that the dog is unable to properly grown new hairs to replace dead ones as they are shed.

    Treatment

    • Your veterinarian can treat ringworm with topical creams and oral anti-fungal medications. Medicated shampoos and an injected insecticide can clear the mite infections that cause mange. Cushing's disease can be treated by removing the tumor on your dog's adrenal glands, either through chemotherapy or surgery. Your veterinarian can give your dog deworming medication that will clear internal parasites such as tapeworms out of his system.

    Considerations

    • Some dog diseases that cause problems with a dog's hair can be passed on to other animals and to humans, such as ringworm and mange. Tapeworm can also be passed from dog to dog. If Cushing's disease is left untreated, you dog will probably only live another two years. Once you treat your dog for the disease, his hair should grow back and return to its normal appearance.