Allergic Dermatitis in Cats

Purebred cats have a higher rate of reported dermatitis than mixed breed cats, but this condition can affects all felines. The most common symptom associated with allergic dermatitis is chronic pruritus manifesting in self-traumatizing licking biting and scratching. Allergic dermatitis can be caused by any element in the area that the feline’s immune system views as hazardous, but fleas, mites, lice and pollen are the typical culprits. Allergic dermatitis in cats can progress from mild to severe in a short period of time, resulting in secondary skin infections and health conditions, so a feline with suspected allergic dermatitis should be treated by a veterinary professional.

Allergic dermatitis in cats is known as feline atopic dermatitis. Feline atopic dermatitis is the term veterinarians use to describe a pruritic disease of a hypersensitive reaction to environmental or inhaled allergens. A hypersensitive immune system creates specialized antibodies to destroy a potentially harmless element, characterized as an allergy. Although a feline is born with a naturally hyperactive immune system, hypersensitivities often go unnoticed until the cat reaches adulthood. 

The most common symptom associated with allergic dermatitis is chronic pruritus manifesting in self-traumatizing licking, biting and scratching. Manipulated areas are unusually isolated to the abdomen, forelegs, pinnae (outside of the ear), neck and face.  

• Scratching and clawing at the skin
• Chewing or biting at the skin
• Rubbing of the face against objects
• Licking of the skin
• Hair loss
• Depression
• Poor hair coat
• Rough appearance

Allergic dermatitis in cats is associated with a number of cutaneous allergy reaction patterns including feline eosinophilic skin disease, miliary dermatitis, cervicofacial dermatoses and lesion associated self-induced alopecia. Feline indolent ulcers, feline eosinophilic granulomas and feline eosinophilic plaques are also grouped with allergic dermatitis as they all have common underlying causes including: 

• Cutaneous neoplasia
• Dermatophytosis
• Autoimmune disease (the immune system attacks itself)
• Allergies to food
• Hypersensitivity to mosquito bite 
• Various mite infections (Otodectes, Sarcoptes, Notoedres, Demodex, Cheyletiella)
• Flea allergy 
• Mold spores
• Household dust mites
• Plant pollen

The veterinarian will begin the diagnosis of allergic dermatitis by reviewing your cat’s medical history and performing a physical examination. During the physical examination, the veterinarian will search for any evidence of flea, lice or mite infestation, as these external parasites are common contributors to feline atopic dermatitis. Fleas can be detected using a flea comb. A flea comb is a specialized comb that can pick up flea dandruff (flea feces) to be examined in a clinic setting. Detecting mites and lice will require a skin scraping, a simple test that scrapes the top layer of the skin, removing particles to be examined under microscopic view.  

If external parasites are not found, the veterinarian may then perform intradermal allergy testing or hyposensitization procedures. An intradermal test will involve clipping the feline's hair on one side of the chest and administering small volumes of allergen proteins into the skin. The skin will react to the allergen it has a hypersensitivity to by localized inflammation and the doctor will then be clued in to what is causing the feline condition. Several cat owners choose not to have this diagnostic test completed as shaving a feline’s hair can cause a change in coat coloration when it grows back. Therefore, a serologic allergy test may be preferred as this test uses a blood sample to send off to a laboratory where the levels of allergens will be compared to antibodies.  

Allergic dermatitis in cats can be treated in a number of ways, including allergen avoidance, symptomatic therapy, immunotherapy or immune suppressive therapy. 

Allergen Avoidance

Removing your cat from the allergen source or keeping the allergen away from the feline. 

Symptomatic Therapy

Antimicrobials, medicated shampoos, ointments, supplements and other medications may be used to treat the symptoms associated with allergic dermatitis. 

Immunotherapy

The process of desensitizing the cat to the allergen through use of the allergen proteins. 

Immunosuppressive Therapy

Treating the cat’s condition with steroids and cyclosporine drugs to diminish immune response.

The prognosis for allergic dermatitis in cats is very good. The veterinarian will need to follow-up with your feline and ensure the chosen treatment plan is working efficiently to either control or eliminate your cat’s allergic response. Sometimes felines grow out of allergic dermatitis as they are not affected by the allergen as they grow older, whereas others need continuous therapeutic care for their entire lives. Talk to your veterinarian about the best treatment plan and outlook for your cat, as his or her condition is likely to change over time.