Cats are private about itching. Instead of scratching where you can see it, many simply groom more: licking their belly bald, pulling out fur on the inner thighs, or chewing at their legs when you are not looking. Other cats get tiny scabs along the back or raw, scratched skin on the head and neck.
All of these can be signs of an itchy cat. (For dogs, see our guide to why dogs get itchy.) This guide covers the most common causes and what your vet is likely to check.
If your cat has bald patches, see also our guide to hair loss in cats.
Signs your cat may be itchy
The Cornell Feline Health Center lists excessive scratching, licking or chewing of the fur, fur loss, and scabby, scaly or flaky skin as common signs of skin disease. [1]
Veterinary dermatologists describe four typical patterns in itchy, allergic cats: [2][3]
- Miliary dermatitis: many tiny crusts or scabs, often easier to feel than see, especially along the back and neck
- Self-induced alopecia: hair loss from overgrooming, often symmetrical on the belly, flanks or inner thighs. The skin underneath may look normal.
- Head and neck itch: scratches, scabs and raw areas on the face, ears and neck
- Eosinophilic lesions: raised, red or ulcerated plaques or sores, including on the lips
These patterns tell your vet the cat is itchy, but none of them points to one specific cause. A large multicenter study of 502 itchy cats found that the patterns were not specific to any single diagnosis. [2]
What causes itch in cats?
In that study of 502 itchy cats from several countries, diagnoses were: [2]
- Flea allergy: 29%
- Food allergy: 12%
- Environmental (non-flea, non-food) allergy: 20%
- Other diseases that cause itch: 24%
- The remaining 15% had signs of allergy but did not complete a food trial, so they could not be classified.
1. Fleas and flea allergy
Flea allergy was the single most common diagnosis in the study above. [2] It happens when the immune system overreacts to proteins in the saliva fleas leave behind when they bite, and in warm climates it is the most common itchy skin disease of both dogs and cats. [4]
You may never see a flea. Itchy pets often swallow or remove fleas and flea dirt while grooming, so an allergic cat may carry very few. Finding no fleas or flea dirt does not rule out flea allergy. [4]
What helps: flea control works when it covers the cat, every other pet in the home, and the home and yard; skipping one of them is a common reason it fails. [1][4] Your vet may recommend a strict flea control trial even if you have not seen fleas.
Important safety warning: never use a dog flea product on a cat unless your vet says it is labeled for cats. Cats handle a group of insecticides called pyrethroids poorly, and permethrin, which is found in some dog products, can poison them. [4] Signs can include ear flicking, muscle tremors, vomiting, refusing food and seizures, and it can be fatal. [4] A cat can also be exposed by grooming or cuddling a dog that was recently treated. Contact your vet immediately if this happens.
2. Food allergy
Food allergy accounted for 12% of itchy cats in the large study, and it looked exactly the same as environmental allergy. [2] An evidence review found that the most common food allergens in cats are beef, fish and chicken. [5]
There is no reliable blood test for food allergy. The way to find out is an elimination diet trial with a diet chosen by your vet, fed strictly with no other food or treats, followed by a re-challenge with the old food. International veterinary guidelines state that food allergy must be ruled out before environmental allergy can be diagnosed in cats. [3] Cornell notes that food allergies are usually managed by feeding a diet that does not contain the components the cat is allergic to. [1]
3. Environmental allergy (feline atopic skin syndrome)
Cats can be allergic to allergens in their environment, a condition now called feline atopic skin syndrome. [3] Cornell lists allergies to airborne particles among the most common causes of skin disease seen at its hospital. [1] Food allergy can occur alongside it, and some cats also have asthma. [3]
According to the International Committee on Allergic Diseases of Animals (ICADA), this is a diagnosis of exclusion: fleas and flea allergy, other parasites, infections and food allergy must be ruled out first. [3] In the 502-cat study, young adult, purebred and female cats appeared more likely to have this type of allergy. [2]
4. Parasites other than fleas
Mites, including ear mites, can cause itching in cats. [1] For feline scabies, Demodex and other skin mites, see mange in cats. Your vet may use skin scrapings, combing, tape samples and ear swabs, or a trial treatment, to look for them. For head shaking and ear scratching, see cat ear problems. Lice are now rare in cats but can still turn up; see lice on dogs and cats.
5. Infections
Bacterial and fungal infections (including ringworm) can cause hair loss and sometimes itch. [1] Ringworm can spread to people and other pets, so it is worth testing for in cats with patchy hair loss. Blackheads, bumps or crusts on the chin are covered in cat chin acne. Lip ulcers and raised red plaques are covered in eosinophilic granuloma complex in cats.
“It’s just stress,” or is it?
Overgrooming is often blamed on stress or boredom, a diagnosis called psychogenic alopecia. It does exist, but research suggests it is diagnosed too often.
In a study of 21 cats referred with a presumptive diagnosis of psychogenic alopecia, a full workup found a medical cause of itch in 16 cats (76%). Only 2 cats (10%) had purely psychogenic alopecia, and 3 more had both a behavioral and a medical cause. Adverse food reaction was diagnosed in 12 cats (57%). [6] The authors concluded that psychogenic alopecia is overdiagnosed and that thorough testing should be done before blaming behavior. [6]
So if your cat is overgrooming, ask your vet about ruling out fleas, food allergy and other medical causes before assuming it is stress. Reducing stress and enriching your cat’s environment is always worthwhile, but it should not replace a medical workup.
What your vet will usually do
A typical workup goes step by step, following the order of exclusion that ICADA describes: [3]
- History and exam: when it started, whether it is seasonal, diet, other pets, outdoor access.
- Rule out fleas with combing and a strict flea control trial for every pet in the home.
- Rule out other parasites with skin and ear samples or trial treatment.
- Check for infections, including ringworm and bacterial or yeast infection.
- Elimination diet trial to test for food allergy.
- Diagnose environmental allergy if itch remains and other causes are excluded. Dermatologists often use allergy tests to support this diagnosis. [3]
This takes time and patience, but it is the most reliable way to find the real cause.
When to see your vet
Book a visit if your cat:
- Is licking, chewing or pulling out fur, or has bald patches
- Has tiny scabs, raw areas or sores
- Is scratching the head, neck or ears
- Has red, smelly or dirty ears
Go promptly if there are open wounds, swelling, a sore on the lip that is growing, or if your cat seems unwell, stops eating or hides. Call immediately if your cat has tremors or seizures after a flea treatment. [4]
Frequently asked questions
Why is my cat licking its fur off?
Overgrooming is most often a sign of itch. In a study of cats presumed to have stress-related overgrooming, 76% actually had a medical cause, most often food allergy. [6] Fleas, food allergy and environmental allergy are the main causes of itch in cats. [2]
My indoor cat has no fleas. Could it still be flea allergy?
Yes. Cats groom away fleas and flea dirt, and an allergic cat can react to just a few bites, so finding no fleas does not rule it out. [4] Fleas can also come indoors on people and other pets. A strict flea control trial for all pets is the usual way to rule it out. [1][4]
What foods are cats most often allergic to?
An evidence review found beef, fish and chicken to be the most common food allergens in cats. [5]
What are the small scabs on my cat’s back?
Many tiny scabs, called miliary dermatitis, are a common sign of an itchy, allergic cat. [2][3] Flea allergy is a frequent cause, but food and environmental allergies can look the same. [2]
Can I use my dog’s flea treatment on my cat?
No, unless your vet confirms it is labeled for cats. Some dog products contain permethrin, which cats cannot break down well and which can poison them. [4]
Is overgrooming in cats caused by stress?
Sometimes, but less often than many people think. In one study, only 10% of cats presumed to have stress-related hair loss had a purely behavioral cause. [6] Ask your vet to rule out medical causes first.
The bottom line
Itchy cats often hide it by overgrooming. Fleas, food allergy and environmental allergy are the most common causes, and they look alike, so a step-by-step workup with your vet is the way to the right answer. Stress is a real but overused explanation; rule out medical causes first.
See your vet if your cat has bald patches, scabs or is grooming more than usual, and immediately if your cat trembles or seizes after a flea treatment.
This article is for general information only and is not a substitute for professional veterinary advice, diagnosis or treatment. Always consult your veterinarian about your pet’s health. If you think your pet has a medical emergency, contact your veterinarian or an emergency animal hospital right away.
Sources
- Cornell Feline Health Center. Feline Skin Diseases. Cornell University College of Veterinary Medicine. https://www.vet.cornell.edu/departments-centers-and-institutes/cornell-feline-health-center/health-information/feline-health-topics/feline-skin-diseases
- 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. doi:10.1111/j.1365-3164.2011.00962.x. https://pubmed.ncbi.nlm.nih.gov/21410570/
- 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 (ICADA). Veterinary Dermatology. 2021;32(1):26-e6. doi:10.1111/vde.12935. https://pubmed.ncbi.nlm.nih.gov/33470017/
- Torres SMF. Flea Bite Allergy: Dogs and Cats. Small and Large Animal Dermatology Handbook, Vol. 1. University of Minnesota, 2025 (CC BY 4.0). https://open.lib.umn.edu/animaldermatology/chapter/flea-bite-allergy-dogs-and-cats/
- Mueller RS, Olivry T, Prelaud P. Critically appraised topic on adverse food reactions of companion animals (2): common food allergen sources in dogs and cats. BMC Veterinary Research. 2016;12:9. doi:10.1186/s12917-016-0633-8. https://pmc.ncbi.nlm.nih.gov/articles/PMC4710035/
- Waisglass SE, Landsberg GM, Yager JA, Hall JA. Underlying medical conditions in cats with presumptive psychogenic alopecia. Journal of the American Veterinary Medical Association. 2006;228(11):1705-1709. doi:10.2460/javma.228.11.1705. https://pubmed.ncbi.nlm.nih.gov/16740071/