Itching and Scratching (Pruritus) in Cats

Summary

The sensation of itchiness (pruritus) in a cat can be caused by many things, most often fungal infections (ringworm), parasites (like fleas or mites), and allergies (to food, fleas, or airborne particles). 

Scratching, as well as biting, licking and rubbing, is a response to the itchy sensation and can have unhealthy impacts - such as damage to the skin, open sores, and hair loss. Skin damage is vulnerable to the development of secondary bacterial or fungal infections which add to the itch, thereby increasing the evidence of pruritus in the absence of treatment.

Rarely does a cat scratch, lick, or chew without a reason, so finding the source of the itch is important. The challenge for a pet owner or a vet is that the source of the irritant is often not obvious from looking at the irritated skin alone. For example, just because there aren’t visible fleas does not rule out flea allergy dermatitis. Additionally, the wide variety of conditions that can cause itch create skin symptoms that look alike, so veterinarians typically use a combination of diagnostic testing and therapeutic trials to determine the best plan for keeping an itchy cat comfortable. 

Treatment for an itchy cat is determined based on the underlying cause. Corticosteroids are sometimes indicated as symptomatic therapy for itch relief in cats. 

The outlook for itchy cats also depends on the underlying cause. Allergies cannot be cured so allergic cats are expected to be itchy any time they are exposed to their allergens if they are not on allergy medications. Itch due to other causes like infections, wound healing, or parasites is expected to fully resolve once the trigger is removed.

Guidelines

Itchiness (pruritus) is the most common symptom of skin disease in almost all animals, including cats.

Itchiness itself isn’t cause for concern, but depending on what is causing the itchiness and how much damage the scratching is doing to the cat’s skin, it is important to find out what is causing the itchiness, and treat it appropriately.

Possible Causes

The symptom of itch is most commonly associated with a variety of skin disorders, including:

Ringworm - This fungus typically creates dry, gray, scaly patches on cats (and other animals). The fungal spores can be easily picked up in the environment, but require compromised (scratched, shaved, or irritated) skin to take root. 

Fleas - Even if there are no obvious fleas, itchiness in cats is most often caused by a flea infestation or flea allergy dermatitis. 

Flea allergy dermatitis (FAD) - FAD is an allergic reaction to flea saliva. The cat’s body excessively responds to the saliva as if it were harmful. For an allergic cat, a single flea bite can trigger the allergic response. 

Mites - pruritus in cats can be caused by the mite Notoedres cati. Feline mites cause scabby, scaly skin that typically starts on the edges of the ears and spreads to the face and eventually the whole body (called mange). 

Food Allergy - A cat can develop hypersensitivity to a protein, carbohydrate, preservative, or dye in its diet. There are no tests to identify the allergen. 

Airborne Allergies - Cats with Atopic dermatitis can develop hypersensitivity to pollen, house dust mites, mold spores and other commonplace airborne particles. 

In rare instances, excessive itch can be a manifestation of a behavioral problem or neurologic disorder. Feline hyperesthesia syndrome is an example of this. Feline hyperesthesia syndrome (FHS) is characterized by hypersensitivity to touch and twitching skin.

Risk Factors

Itch can present along a spectrum of mild to severe. Some veterinarians have pet parents track their cat’s itch level on a scale of one to ten, when one is not itchy at all and ten is so itchy the cat interrupts itself from activities like eating or playing to scratch.

Testing and Diagnosis

The veterinary approach to determining the underlying cause of itch starts with getting a thorough health and lifestyle history of the animal. Taking a history is helpful to not only better characterize the nature of the itch, but also to fully evaluate the cat’s overall health status. 

The next step is a thorough physical examination followed by standard skin diagnostic tests: 

• Flea combing 

• Skin scrape to look for mites

• Fungal culture to look for fungal skin pathogens

• Skin cytology to look for pathogens and inflammatory or abnormal cells in any skin lesions

Similar symptoms

Pruritus may be mistaken for behavioral symptoms that are not actually related to itching sensation such as overgrooming and hyperesthesia syndrome.

Associated Symptoms

Pruritus may lead to secondary symptoms including hair loss, scratches on the skin, rashes, and infection.