What Are the Causes of Dog Hair Loss, Scratching and Oily Coat?

A condition known as seborrhea in dogs causes an oily coat, itchy skin and hair loss, depending on the severity of the disease. Seborrhea occurs as both a primary condition and a secondary one, caused by genetics, certain underlying medical conditions, skin infections or a parasitic infestation of the skin. Give your dog relief from this unpleasant condition by treating the underlying cause of the disease or topically treating the skin and coat.

  1. Oily Seborrhea

    • Seborrhea oleosa, also called oily seborrhea, leads to the excessive shedding of scales of dead skin on the dog's coat and excess oil production by the sebaceous glands. The overproduction of oil can lead to the blockage and infection of the hair follicles, causing folliculitis, which results in severe itching of the skin. When the dog scratches at the itch, the skin becomes irritated and breaks open, leading to secondary bacterial or fungal infections. This also causes hair loss on the coat, also called alopecia. In addition, the excess oil on the coat provides a breeding ground for bacteria and yeast, leading to further skin problems, itchiness and a rancid odor.

    Types and Causes

    • Primary idiopathic seborrhea is a hereditary condition, usually seen in certain breeds, including the American cocker spaniel, English springer spaniel, Labrador retriever, German shepherd, West Highland white terrier, basset hound, Irish setter and Shar-pei, according to WebMD. In dogs affected by primary idiopathatic seborrhea, the genetic disease actually causes the symptoms of itchiness, oily skin and hair loss. Secondary seborrhea results from a primary, underlying medical condition, and is merely a symptom of another disease. Medical conditions such as skin allergies, a hormonal or endocrine disorder, such as hyperthyroidism or pancreatic disease, and nutritional deficiencies can all cause secondary seborrhea. While you can cure secondary seborrhea by treating the underlying medical condition, you can only control the symptoms of primary idiopathic seborrhea.

    Other Causes of Seborrhea

    • Parasites like fleas can cause itching of the skin, which leads to secondary seborrhea and bacterial or fungal skin infections. Flea saliva can cause an allergic reaction in your dog that results in intense itching and hair loss, primarily near the base of the tail, back, thighs, and stomach, when your dog scratches at the fleas. Other types of skin parasites can also result in seborrhea, such as the demodectic mange mite, which mainly affects younger dogs, the cheyletiella mite, sarcoptic mange mite and skin lice. Treating the dog with a topical flea-control product that also targets certain types of mites or lice usually clears up the parasite problem and the seborrhea, requiring no further medication.

    Diagnosis and Treatment

    • To diagnose seborrhea, a veterinarian will take a skin cytology by scraping the skin, perform a physical examination, take blood tests and possibly take a skin biopsy. Once the veterinarian determines the cause of the seborrhea, he will prescribe medication or therapy to treat any possible underlying medical conditions. For secondary infections of the skin, he may prescribe oral or topical antibiotics and antifungal medicines. To provide your dog with topical relief, or if the dog suffers from primary seborrhea, he may also prescribe a shampoo and conditioner for your dog's skin and coat. These shampoos contain ingredients such as coal tar, salicylic acid, sulfur and benzoyl peroxide to remove scales from the skin and excess oil. Certain leave-on conditioners contain ingredients to soothe the dog's itching and provide antibacterial or antifungal relief for secondary infections.