By Dial A Vet Veterinary Team
Cats are discreet about itching. Rather than scratching in front of you, many lick and pull at their fur in private, so the first sign may be a bald belly, thinning fur on the back legs, or tiny scabs you feel while patting. Dermatitis simply means inflamed skin, and in cats it has a handful of usual causes. Working out which one is behind your cat's itch is the key to lasting relief.
Key takeaways
- Overgrooming, hair loss, small scabs and red or raw patches are common signs of itchy skin in cats.
- Flea allergy is the most common cause in Australian cats, even when you cannot find fleas.
- Food allergy, environmental allergy, mites and ringworm are other common causes.
- Never use dog flea products or essential oils on cats. Some are fatal.
- Most cases can be well controlled once the cause is identified.
Signs of dermatitis in cats
- Excessive licking, chewing or pulling out fur
- Hair loss, often symmetrical on the belly, inner thighs or flanks
- Small crusty bumps along the back and neck, which feel like grains of sand (miliary dermatitis)
- Red, raw patches or sores, especially on the head, face and neck from scratching
- Raised, red, ulcerated or linear lesions (eosinophilic granuloma complex), sometimes on the lip, chin or back of the thighs
- Dandruff or greasy skin
- Ear scratching, head shaking or dark ear discharge
Cats who overgroom often vomit more hairballs, which can be another clue.
Common causes
Flea allergy
Flea allergy dermatitis is the most common skin allergy in cats. A few bites are enough to cause intense itching, and cats groom fleas away efficiently, so you may never see one. Look for flea dirt: tiny black specks that turn reddish-brown on damp paper. Indoor cats can get fleas too, brought in by dogs or people. Read more in our article on flea allergy dermatitis in cats.
Food allergy
Usually a reaction to a protein such as fish, chicken or beef. It can cause itch at any age and at any time of year, often around the head and neck, sometimes with vomiting or diarrhoea.
Environmental allergy
Vets now call this feline atopic skin syndrome. Cats react to pollens, dust mites or moulds, which may cause seasonal or year-round itch.
Mites and parasites
Ear mites, Cheyletiella (walking dandruff), Demodex and, uncommonly in Australia, Notoedres can all cause dermatitis. Our article on mange in cats explains each.
Ringworm
A fungal infection, not a worm. It causes patchy hair loss with scaling and is not always itchy. It can spread to people and other pets, so it is worth ruling out, particularly in kittens and longhaired cats.
Bacterial and yeast infections
Usually secondary to allergy or scratching, but they add to the itch.
Stress and behaviour
Some cats overgroom when stressed, but this is diagnosed only after medical causes are ruled out.
When to see a vet
Book an appointment if your cat is losing fur, scratching, overgrooming or has scabs. Seek prompt care if:
- The skin is raw, bleeding, or infected
- Your cat stops eating, loses weight or seems unwell
- There are open sores on the lip or face
- Other pets or people in the house develop skin lesions
How vets diagnose dermatitis in cats
Your vet will ask about your cat's lifestyle, parasite prevention, diet and other pets, then examine the skin and ears. Tests may include:
- Flea combing and checking for flea dirt
- Skin scrapings and tape impressions for mites
- Ringworm testing, such as a UV lamp examination, fungal culture or PCR
- Skin cytology to look for bacteria and yeast
- An elimination diet trial for food allergy, usually for about eight weeks
- Allergy testing in some cats with suspected environmental allergy
Diagnosis is often a step-by-step process, starting with strict flea control.
How it is treated
Treatment depends on the cause and may include:
- Effective, cat-safe flea control for every pet in the house, every month, all year round
- A prescription elimination diet for suspected food allergy
- Treatment for mites or ringworm, including environmental cleaning for ringworm
- Medication to control itch and inflammation, chosen and prescribed by your vet
- Treatment for secondary infections
- Environmental enrichment for stress-related overgrooming
What you can do at home
- Use only flea treatments registered for cats, and treat all pets.
- Wash bedding regularly in hot water.
- Note when the itch is worse and any changes in food, routine or environment.
- Keep your cat's diet consistent while you investigate.
Avoid:
- Dog flea products. Many contain permethrin, which causes tremors, seizures and death in cats.
- Essential oils, including tea tree oil, whether on the skin or in diffusers.
- Human creams and ointments, which cats lick off.
FAQ
Why is my indoor cat itchy?
Fleas can still reach indoor cats via other pets, people or visitors. Food allergy and environmental allergy also affect indoor cats.
Can cat dermatitis spread to people?
Allergies cannot, but ringworm and some mites can. Your vet can test for these.
Is overgrooming always stress?
No. Most overgrooming has a medical cause, usually allergy or parasites.
How long until I see improvement?
With effective flea control, many cats improve within a few weeks. Food trials take about eight weeks.
Talk with a vet
If your cat is overgrooming or has scabs, a Dial A Vet veterinarian can look at photos, help narrow down the causes and suggest cat-safe next steps. Book a Dial A Vet consult. If your cat has been exposed to a dog flea product and is twitching, call an emergency vet straight away.
References
- Hobi S, Linek M, Marignac G, et al. Clinical characteristics and causes of pruritus in cats: a multicentre study on feline hypersensitivity-associated dermatoses. Veterinary Dermatology. 2011;22(5):406-413.
- Santoro D, Pucheu-Haston CM, Prost C, Mueller RS, Jackson H. Clinical signs and diagnosis of feline atopic syndrome: detailed guidelines for a correct diagnosis. Veterinary Dermatology. 2021;32(1):26-e6.
- International Cat Care: Permethrin poisoning in cats
- Merck Veterinary Manual: Flea allergy dermatitis
Disclaimer: Educational only. This page does not replace an examination or advice from your own veterinarian. If you are worried about your pet right now, contact your local vet or nearest emergency animal hospital.
