Cat Hair Loss (Alopecia) -Causes & Treatment

Also known as alopecia, hair loss isn’t a disease in itself but a symptom of an underlying condition. All cats lose hair (shedding), but alopecia is defined as an excessive loss of hair.


The cause of hair loss can be split into itchy/self-induced or non-itchy/non-self-induced. Below are some possible causes:


  • Flea allergy dermatitis: Allergy to the saliva from the flea bite.
  • Food allergy: Allergy to a protein in food. Fish, beef, and chicken are the most common causes of food allergy.
  • Inhalant allergy: Allergy to an inhalant such as cigarette smoke.
  • Notoedric mange: A scaly skin condition caused by a species of spider-like parasites known as Notoedres cati.
  • Ear mites: Tiny spider-like parasites which live in and around the ears causing intense itching.
  • Psychogenic: Compulsive over-grooming.
  • Pyoderma:  Bacterial infection of the skin.
  • Abscess: Walled off collection of pus located in the tissue. Usually, the cause is a cat bite.


  • Hyperthyroidism: Usually caused by a benign tumour of the thyroid gland.
  • Stress: Surgery, a new pet, new baby, illness etc.
  • Cushing’s syndrome (hyperadrenocorticism): Excessive levels of cortisol in the blood either caused by the adrenal glands or the administration of steroids.
  • Ringworm: A highly contagious, generally superficial fungal infection of the skin, fur and claws. It is caused by a fungus of the genus Microsporum and Trichophyton.
  • Feline acquired symmetrical alopecia: The exact cause isn’t known, it is believed to be a hormonal disorder.
  • Drug reaction (topical, injected).
  • Telogen defluxion: Hair loss occurs during the resting phase of the hair growth cycle).
  • Anagen defluxion: Hair loss occurs during the growing phase.
  • Sunburn
  • Seborrhea: Excess secretion of sebum.
  • Stud tail: Hypersecretion of the glands located at the base of the tail, males are most commonly affected.


Your veterinarian will perform a complete physical examination and pay careful attention to the location, size, and shape of the hair loss if any other symptoms are also present and obtain a medical history from you. He will need to establish if the cat has been scratching, itching, how long it has had symptoms if it has recently had any medication (topical flea/worming products, injection etc).

Diagnostic workup

  • Fungus culture: To look for ringworm.
  • Trichogram: This is a microscopic examination of the hair root. Broken tips indicate that hair loss is self-induced.
  • Food elimination trial: Your veterinarian will place your cat on a food trial which usually lasts between 8-12 weeks. During this time, you must not give your cat any other foods, vitamins, minerals or chewable medications apart from the prescribed diet. If the allergy clears up after the specified time then a food allergy is the likely cause. The diet may be homemade or a prescription diet. After the trial, if the cat’s allergies have cleared up it will go back onto his regular food to see if symptoms return.
  • Specific blood tests: To check for hyperthyroidism and Cushing’s syndrome.
  • Skin scrapings: A scalpel blade to gently scrape along the surface of the skin to look for the presence of mites.


Treatment depends on the underlying cause of the alopecia and may include.

  • Ringworm: Lime sulfur dips, anti-fungal drugs.
  • Food allergies: Switching to a novel or low allergenic diet.
  • Hyperthyroidism: Radioactive iodine to destroy the tumour or surgery to remove it followed by lifelong replacement of thyroid hormones.
  • Cushing’s syndrome: Gradual withdrawal of corticosteroids if veterinary induced, surgical removal of the affected adrenal gland if a tumour is involved, surgical removal of both adrenal glands if a pituitary tumour is the cause.
  • Inhalant allergy: Avoidance of the allergen if possible.
  • Notoedric mange: Clipping, weekly lime sulfur dips, Revolution.
  • Ear mites: Removal of the exudates, an insecticide such as Revolution.
  • Psychogenic alopecia: Behaviour modification, keeping your cat in a stress-free environment and drug therapy (if other methods fail).
  • Pyoderma: Antibiotics and clipping the affected area.
  • Abscess: Draining of the abscess and antibiotics.
  • Feline acquired symmetrical alopecia: Hormones, although not all veterinarians recommend this.
  • Drug reaction: Switching or discontinuing medications.
  • Seborrhea: Shampoos, omega-3 fatty acids, antibiotics.
  • Stud tail: Antiseborrheic shampoos, neutering (where possible).
  • Sunburn: Topical or oral corticosteroids and pain killers where necessary.

Image courtesy Sarah R, Flickr


  • Julia Wilson, 'Cat World' Founder

    Julia Wilson is the founder of Cat-World, and has researched and written over 1,000 articles about cats. She is a cat expert with over 20 years of experience writing about a wide range of cat topics, with a special interest in cat health, welfare and preventative care. Julia lives in Sydney with her family, four cats and two dogs. Full author bio

    View all posts