Why a Dog Loses Hair & Smells Bad

By Jane Meggitt

If your dog is losing his hair and smells bad, the culprit could be one of several types of skin infections. Take your dog to the vet for an accurate diagnosis and treatment. She will likely take skin samples or perform a biopsy to get to the bottom of your dog's hair loss -- or alopecia -- and foul odor.

Canine Pyoderma

Pyoderma refers to pus in the dog's skin, occurring because of bacterial infection. While pus-filled lesions are always present in pyoderma, the dog may or may not lose hair. The infection causes the skin to smell quite rank. While any dog may develop pyoderma, German shepherds are particularly susceptible. Additional symptoms include:

  • itching
  • crustiness
  • or scaliness.

Topical and systemic antibiotic treatment usually cures the condition, but therapy often lasts a month or more.

Seborrhea in Dogs

Dogs with seborrhea develop greasy coats and skin, and that oiliness often smells quite bad. Hair loss occurs because the dog scratches at the areas with the oily build-up. Some breeds are genetically predisposed to seborrhea. These include:

  • cocker and springer spaniels
  • dachshunds
  • Labrador and golden retrievers
  • basset hounds
  • Doberman pinschers
  • German shepherds
  • Shar-Peis
  • and West Highland white terriers.

Non-hereditary seborrhea results from allergies, parasite infestation and endocrine and other disorders. There's no real cure for the condition, but your vet can prescribe medications and recommend supplements to control the greasiness. Sulfur shampoos designed for canines can stem the oil and smell, as can cleansers containing acne control products such as benzoyl peroxide or salicylic acid.

Any secondary infections due to seborrhea require antibiotic or antifungal topical or systemic therapy, according to the results of skin testing. Feeding your pet a high-quality dog food and giving him omega-3 fatty acid supplements can improve skin and coat quality.

Yeast Infection

Skin with a strong stench is often indicative of a yeast infection, usually with the Malassezia fungus. Your dog doesn't just lose hair -- his skin may start resembling that of an elephant. He itches constantly, and the infection can spread all over his body. Certain breeds are also predisposed to yeast infections, and these include:

  • basset hounds
  • chihuahuas
  • cocker spaniels
  • poodles
  • dachshunds
  • Australian, silky and West Highland white terriers
  • Lhasa apsos
  • Maltese
  • and Shetland sheepdogs.

An allergy can start the yeast infection ball rolling, as can seborrhea -- a double whammy for a dog already affected with an oily, smelly skin condition. Treatment consists of shampooing at least twice weekly with anti-yeast and degreasing cleansers, along with oral antifungal drugs such as ketoconazole or fluconazole. The underlying cause requires diagnosis and treatment. or the yeast infection will never be completely eradicated. For allergies, that may require immunotherapy shots, food trials or medications to control reactions, whatever the trigger proves to be.