Why Is My Cat Losing Hair? 6 Causes and What to Do

Why Is My Cat Losing Hair? 6 Causes and What to Do

Short answer: Cats lose hair most often from overgrooming caused by stress or allergies, fleas, or a skin condition — and bald patches, red skin, or sores always deserve a vet check. Start by ruling out fleas and a recent stressor, then work through food, skin, and medical causes with your vet.

Finding clumps of fur on the sofa is normal in shedding season. Finding bald patches, thinning flanks, or a belly that has gone bare is not. Hair loss in cats, called alopecia, is a symptom, not a diagnosis, and the cause decides the fix. The good news is that most causes are treatable once you find them.

1. Overgrooming from stress

The single most common cause of hair loss in indoor cats is overgrooming. A stressed cat licks the same spot — usually the belly, inner thighs, or forelegs — until the fur thins or disappears. The skin underneath often looks normal, which is the clue: this is licking, not a rash. Common triggers are a new pet, a house move, a new baby, building work, or a change in routine. Fix the stressor where you can, add hiding spots and vertical space, and keep play sessions daily.

2. Fleas, even if you cannot see them

Many cats are allergic to flea saliva, so a single bite can set off intense itching and overgrooming. You may never see a flea — cats groom them away. Check for tiny black specks (flea dirt) in the fur, especially around the tail base and belly. If in doubt, treat with a vet-recommended flea product and treat all pets in the home, not just the one losing hair.

3. Food and environmental allergies

Allergies to food proteins, pollen, or dust mites cause itchy skin, and the cat's answer is to lick and scratch. Signs that point to allergy are itching around the head and neck, ear irritation, and hair loss that comes and goes with the seasons. A vet-supervised elimination diet is the reliable way to test food allergy — switching foods at random rarely gives a clear answer.

4. Skin infections and ringworm

Ringworm is a fungus, not a worm, and it causes circular patches of hair loss, often with flaky skin. Bacterial skin infections cause redness, sores, and crusts. Both need veterinary diagnosis and treatment, and ringworm can spread to people and other pets, so do not wait it out. Keep the cat's bedding washed and avoid sharing brushes between pets until it is cleared.

5. Pain underneath the bald patch

Cats lick painful areas, including joints and bladders. A cat with arthritis may lick its hips bare; a cat with bladder pain may lick its belly. If the bald patch sits over a joint, or your cat also strains in the litter box, cries, or moves stiffly, tell your vet — the hair loss may be pointing at pain, not skin.

6. Hormones and medical causes

Less common, but important: thyroid problems, Cushing's disease, and other hormonal conditions can thin the coat, usually symmetrically on both sides. These cats often show other signs too — weight change, appetite change, or extra thirst. Blood tests settle this quickly, and treatment usually brings the coat back.

What to do this week

First, check for fleas and treat if needed. Second, note any recent change in the home that could be stressing your cat, and add a safe hiding spot and a daily play session. Third, photograph the bald patches so you can show your vet how fast they are changing. Do not use human creams, essential oils, or anti-itch sprays on a cat — many are toxic to cats. For a trusted overview of feline hair loss causes, see the VCA Hospitals guide: VCA: Hair Loss in Cats.

Stress is the thread through many cat problems, so the same calm-home steps that help a cat that hides all the time help here too — and regular grooming is far easier when you avoid the common cat grooming mistakes that irritate skin further.

When to call the vet straight away

Call promptly if the skin is red, broken, or smelly, if hair loss is spreading fast, if your cat is also vomiting, losing weight, or drinking much more than usual, or if you suspect ringworm. Most hair loss is slow and fixable, but these signs mean the cause needs identifying now, not at the next routine visit.