Key Characteristic: A single flea bite can trigger a severe reaction lasting for weeks.

Treatment:

• Strict, year-round flea control on all pets
• Corticosteroids for short-term inflammation control
• Antibiotics for secondary infections
• Omega-3 fatty acid supplements
• Soothing medicated baths

Food Allergies

Cause: An adverse immune response to specific food proteins.

Common Allergens:

• Beef
• Fish
• Chicken
• Dairy products
• Wheat
• Corn
• Soy

Symptoms:

• Itchy skin (face, ears, neck, belly)
• Chronic ear infections
• Gastrointestinal issues (vomiting, diarrhea)
• Poor coat condition
• Recurrent skin infections

Diagnosis:

• An 8-12 week elimination diet trial
• Novel protein or hydrolyzed protein diet
• Strict avoidance of other food, treats, or flavored medications
• Challenge with original food to confirm the allergen

Treatment:

• Lifelong avoidance of the trigger protein
• Commercial limited-ingredient diets
• Veterinary prescription hypoallergenic diets
• Home-cooked diets (with guidance from a veterinary nutritionist)

Atopic Dermatitis (Environmental Allergies)

Cause: An allergic reaction to environmental allergens such as pollens, molds, and dust mites.

Symptoms:

• Itchy skin (face, ears, paws, belly, armpits)
• Overgrooming
• Hair loss
• Skin thickening and darkening over time
• Recurrent ear infections
• Often follows seasonal patterns

Common Allergens:

• Pollen (trees, grasses, weeds)
• Dust mites
• Mold spores
• Dander from other animals
• Storage mites

Diagnosis:

• Rule out other causes (fleas, food)
• Intradermal allergy testing (skin)
• Blood testing (serum IgE)
• Response to trial therapy

Treatment Options:

• Allergen-specific immunotherapy (hyposensitization)
• Corticosteroids
• Atopica (cyclosporine)
• Apoquel (oclacitinib) – limited use in cats
• Antihistamines (limited effectiveness in cats)
• Fatty acid supplements

Contact Allergies

Cause: Direct skin contact with an allergen.

Common Triggers:

• Certain fabrics (wool, synthetics)
• Cleaning products
• Floor treatments
• Plastic food bowls
• Bedding materials
• Collars or topical products

Symptoms:

• Redness at the contact site
• Itching
• Hair loss
• Blisters or hives (rare)

Treatment:

• Identify and remove the trigger
• Topical treatments for affected areas
• Antihistamines if needed
• Usually resolves once the allergen is removed

Recognizing Allergy Symptoms

Skin Signs

Primary Symptoms:

• Itching (pruritus) – the most common sign
• Redness (erythema)
• Small red bumps (papules)
• Hives (urticaria) – rare in cats

Secondary Signs (from self-trauma):

• Hair loss (alopecia)
• Scabs and crusting
• Open sores
• Skin thickening (lichenification)
• Skin darkening (hyperpigmentation)
• Hot spots (acute moist dermatitis)

Distribution Patterns

Flea Allergies:

• Base of tail
• Inner thighs
• Lower back
• Abdomen

Food Allergies:

• Face and head
• Ears
• Neck
• Belly
• Inner legs

Atopic Dermatitis:

• Face (especially around eyes)
• Ears
• Paws
• Armpits
• Groin
• Belly

Contact Allergies:

• Area of contact
• Often symmetrical

Other Signs

Ear Problems:

• Head shaking
• Ear scratching
• Red, inflamed ear canals
• Ear discharge
• Odor

Gastrointestinal (food allergies):

• Vomiting
• Diarrhea
• Increased bowel movements
• Flatulence

Respiratory (rare in cats):

• Sneezing
• Coughing
• Watery eyes
• Nasal discharge

Diagnosis Process

Veterinary Examination

History Taking:

• Age of onset
• Seasonal patterns
• Diet history
• Flea control status
• Home environment
• Previous treatments and response

Physical Examination:

• Comprehensive skin examination
• Pattern recognition
• Ear examination
• Overall health assessment
• Body condition scoring

Diagnostic Testing

Rule Out Other Causes:

• Skin scrapings (for mites)
• Fungal culture (for ringworm)
• Flea combing
• Skin cytology (for infection)
• Skin biopsy (for unusual presentations)

Specific Allergy Testing:

Food Trial:

• 8-12 week strict elimination diet
• Novel protein or hydrolyzed diet
• No treats, supplements, or flavored medications
• The gold standard for food allergy diagnosis

Intradermal Allergy Testing:

• Requires sedation
• Small amounts of allergens injected into the skin
• Wheal (hive) formation is measured
• Identifies environmental allergies
• Performed by a veterinary dermatologist

Serum Allergy Testing:

• Requires a blood sample
• Measures allergen-specific IgE
• Less accurate than intradermal testing
• A convenient screening tool

Treatment Approaches

Flea Control (Essential for All Allergic Cats)

Year-Round Prevention:

• Monthly topical or oral products
• Treat all pets in the household
• Treat the environment if an infestation is present

Effective Products:

• Revolution (selamectin)
• Bravecto (fluralaner)
• Advantage Multi
• Comfortis/Credelio (oral)

Medication Options

Corticosteroids:

• Prednisolone is most common
• Highly effective for itching
• Side effects with long-term use
• Best for short courses during flares

Cyclosporine (Atopica):

• Modulates the immune response
• Effective for atopic dermatitis
• Fewer side effects than steroids
• Expensive; takes 4-6 weeks for full effect

Oclacitinib (Apoquel):

• Fast-acting itch relief
• Limited experience in cats
• Expensive; may need combination therapy

Antihistamines:

• Limited effectiveness in cats
• Cetirizine (Zyrtec) is sometimes helpful
• Diphenhydramine (Benadryl) often causes sedation
• Generally disappointing results

Fatty Acid Supplements:

• Omega-3 and omega-6
• Modest benefit
• Takes 6-8 weeks to see effect
• Good adjunct therapy; safe for long-term use

Immunotherapy (Allergy Shots)

Process:

• Based on allergy testing results
• Custom serum is created
• Regular injections (initially weekly, then monthly)
• Gradual allergen desensitization

Success Rate:

• 60-75% improvement
• Takes 6-12 months to see results
• A lifelong commitment
• The most effective treatment for atopic dermatitis

Administration:

• Subcutaneous injections
• Owners can be taught to administer at home
• Requires initial veterinary monitoring

Topical Treatments

Medicated Shampoos:

• Chlorhexidine (antibacterial)
• Ketoconazole (antifungal)
• Oatmeal-based (soothing)
• Frequency: 2-3 times weekly initially

Leave-on Conditioners/Sprays:

• Continue medication on the skin
• Help restore the skin barrier
• Reduce the frequency of baths

Spot Treatments:

• For localized areas
• Hydrocortisone sprays
• Antibiotic ointments for infections

Dietary Management

For Food Allergies:

• Strict avoidance of the trigger protein
• Novel protein diets (rabbit, venison, duck)
• Hydrolyzed protein diets
• Limited ingredient diets
• Home-cooked diets (with veterinary nutritionist guidance)

For Skin Health:

• High-quality protein
• Omega-3 fatty acid supplementation
• Antioxidants
• Avoid high-allergen proteins if atopic

Environmental Control

Dust Mite Reduction

Strategies:

• Wash bedding weekly in hot water
• Use dust mite covers on pillows and mattresses
• Reduce indoor humidity
• Use HEPA air purifiers
• Minimize carpet and upholstery

Pollen Management

During High Pollen Seasons:

• Keep windows closed
• Use air conditioning with HEPA filtration
• Wipe your cat's coat with a damp cloth after being outside
• Consider bathing during peak seasons

Mold Control

• Fix water leaks promptly
• Dehumidify damp areas
• Clean bathrooms regularly
• Use air purifiers
• Remove visible mold

Managing Secondary Infections

Bacterial Infections

Common with Allergic Skin:

• Staphylococcus species
• Enter through the damaged skin barrier
• Worsen itching

Treatment:

• Antibiotics (3-4 weeks minimum)
• Cultures for resistant infections
• Topical chlorhexidine
• Address the underlying allergy

Yeast Infections (Malassezia)

Signs:

• Greasy skin
• Musty odor
• Brownish discharge
• Usually in ears, between toes, and skin folds

Treatment:

• Antifungal shampoos (ketoconazole, miconazole)
• Oral antifungals for severe cases
• Topical treatments
• Ear medications if otitis is present

Long-Term Management

Developing a Treatment Plan

Step 1: Identify and Eliminate Triggers

• Flea control (for all cats)
• Food trial if indicated
• Environmental modifications

Step 2: Treat Symptoms

• Medications for itching
• Treat secondary infections
• Implement topical therapies

Step 3: Long-Term Control

• Immunotherapy if atopic
• Maintenance medications
• Regular bathing if needed
• Ongoing monitoring and adjustment

Monitoring and Follow-Up

Regular Assessment:

• Skin condition
• Itching level (pruritus score)
• Ear health
• Response to treatment
• Side effects of medications

Adjustments:

• Seasonal medication changes
• Dose adjustments
• Treatment additions or subtractions
• Diet modifications

Cost Considerations

Diagnostic Costs

Treatment Costs

Annual Cost Estimates

• Mild Allergies: $500-1,000/year
• Moderate Allergies: $1,000-2,500/year
• Severe Allergies: $2,500-5,000+/year

When to See a Specialist

Consider a Veterinary Dermatologist If:

• The diagnosis is unclear
• Standard treatments are failing
• The disease is severe or widespread
• You are considering immunotherapy
• Presentations are unusual
• Multiple skin conditions are present

The Bottom Line

Feline allergies require patience and persistence to manage effectively. The keys to success are:

1. Accurate diagnosis: Identify specific triggers.
2. Flea control: Essential for all allergic cats.
3. Appropriate treatment: Targeted to the specific allergy type.
4. Consistency: A long-term commitment to management.
5. Regular monitoring: Adjust the plan as needed.

While allergies cannot be "cured" (except some contact allergies and potentially food allergies with strict avoidance), they can be successfully managed to provide your cat with a comfortable, happy life.

Work closely with your veterinarian to develop a comprehensive management plan tailored to your cat's specific allergies and needs.

Last Updated: 2026
Never give your cat human allergy medications without veterinary guidance. Many are toxic to cats.