Diagnosing Cat Hair Loss

Cat hair loss is a relatively common symptom, as well as a naturally occurring process. Most breeds shed their fur twice per year, although individual cats may fall within a spectrum of healthy hair loss. If your cat appears to be shedding an abnormal amount of hair all of a sudden, or if you notice that he has a patchy coat or thin spots, there are a number of possible reasons that may be behind this symptom. The following methods and tests help veterinarians to diagnose the cause of the problem.

Initial Diagnostic Process

Your vet will begin by scanning your pet's medical history and conducting a physical exam in order to determine whether there are any other concurrent symptoms. In particular, he will look for any of the following, which may help to identify the underlying disease or condition that is responsible for your pet's hair loss:

  • Unusual licking or scratching
  • Red, irritated marks on skin
  • Bumps or lesions
  • Discharge
  • Scaly skin
  • Oily sections of skin
  • Hot spots

Following his initial examination, your veterinarian will continue the diagnostic process by performing one or more of the following tests.

Skin Scraping

One of the most common diagnostic tests for pets suffering from hair loss is a skin scraping. This test is quick and non-invasive, and involves sampling a small section of skin for further analysis in the laboratory. Skin scrapings are useful in identifying infections, parasites and other conditions.

Fungal or Bacterial Culture

Cultures are tests used to determine whether your cat is experiencing a bacteria- or fungus-related infection. Infections of these types are quite common, and they occasionally lead to minor hair loss. The culture sampling generally involves a procedure similar to that of a skin scraping.


If your veterinarian suspects that an underlying condition may be contributing to or causing your cat's hair loss, he may order a biopsy of a part of your cat's body. Biopsies range from minor to moderately invasive surgeries and involve removing a small sample of a particular organ or part of your cat's body in order to perform further diagnostic tests. In the case of hair loss, most biopsies would be small samplings of the skin at the affected area.

Allergy Tests

Allergies are frequently the cause of skin and hair problems in cats. While determining if your pet is suffering from an allergy may not be difficult, pinpointing the source of the allergic reaction itself is often a challenge. Typically, veterinarians perform elimination tests in order to determine which allergens your pet is not affected negatively by. Through a process of elimination, your vet can determine which allergen is causing the reaction.

Blood and Urine Tests

Although less common than other diagnostic tests for cats with hair loss, blood and urine tests can be helpful in pinpointing specific health concerns, such as hyperthyroidism, seborrhea and Cushing's disease.

Having determined the cause of your pet's hair loss, you can begin to address his symptoms and the underlying condition. Treatment varies depending upon the cause of the problem, and it's always best to speak with a vet before beginning any treatment plan.