Cat Skin Problems: Allergies, Infections, and Hair Loss

Skin problems are the second most common reason cats visit the veterinarian (after vaccinations). The challenge is that many different conditions look similar -- itching, hair loss, and scabs can be caused by allergies, parasites, infections, or stress. Accurate diagnosis is essential because treatment varies dramatically.

Top Causes of Cat Skin Problems

1. Flea Allergy Dermatitis (FAD)

• The #1 most common skin problem in cats
• Allergic reaction to flea saliva -- one flea bite can trigger weeks of itching
• Symptoms: intense scratching, hair loss (especially lower back, tail base, inner thighs), scabs (miliary dermatitis)
• Treatment: strict flea prevention (Revolution Plus, Bravecto), may need steroids for inflammation
• Key: you may never SEE a flea -- cats groom them off. Absence of visible fleas does not rule out FAD.

2. Environmental Allergies (Atopy)

• Allergic to pollen, dust mites, mold
• Symptoms: itching (face, ears, paws), over-grooming, recurring ear infections
• Usually seasonal initially, may become year-round
• Treatment: antihistamines, steroids, immunotherapy (allergy shots), Atopica (cyclosporine)

3. Food Allergies

• Immune reaction to dietary proteins (beef, fish, chicken most common)
• Symptoms: head/neck itching, miliary dermatitis, GI signs
• Diagnosis: 8-12 week elimination diet (blood/skin tests are unreliable for food allergies)

4. Ringworm

• Fungal infection (not a worm) -- highly contagious to cats AND humans
• Symptoms: circular patches of hair loss, scaly skin, crusty lesions
• Diagnosis: fungal culture, Wood's lamp (some strains glow green)
• Treatment: antifungal medication (oral itraconazole), topical treatment, environmental decontamination

5. Psychogenic Alopecia (Over-grooming from Stress)

• Compulsive grooming causing hair loss -- usually on belly, inner legs
• Triggered by: environmental changes, new pets, schedule disruption, anxiety
• Diagnosis: rule out all medical causes first (most "stress grooming" is actually FAD or allergies)
• Treatment: address underlying stress, environmental enrichment, Feliway, anti-anxiety medication if severe

The Miliary Dermatitis Pattern

"Miliary dermatitis" refers to tiny, grain-like scabs scattered across the body -- it is NOT a diagnosis but a reaction pattern that multiple conditions cause:

• Flea allergy (most common cause)
• Food allergy
• Environmental allergy
• Bacterial infection
• Ringworm

When to See the Vet

• Hair loss that does not regrow within 2-3 weeks
• Intense scratching causing skin damage
• Scabs, crusts, or open sores
• Circular bald patches (ringworm -- contagious to humans)
• Skin changes in color, texture, or smell

Frequently Asked Questions

My cat is losing fur on its belly -- is it stress?

Probably not. While psychogenic alopecia (stress-related over-grooming) exists, studies show that 75% of cats initially diagnosed with "stress grooming" actually have an underlying medical cause -- most commonly flea allergy or food allergy. Always pursue medical workup first: flea prevention trial, elimination diet, and dermatological exam. Only diagnose psychogenic alopecia after ruling out all medical causes.