Inflammatory skin diseases are common in cats and cause significant chronic discomfort. Unlike dogs, cats present atopic and allergic skin disease somewhat differently, and parasitic skin disease (particularly feline miliary dermatitis and Notoedres) must always be excluded. Understanding feline dermatological patterns aids effective diagnosis and welfare-centred management.
Distinctive Feline Skin Disease Patterns
Cats express skin disease through a small number of reaction patterns regardless of underlying cause:
- Miliary dermatitis: Multiple small crusty papules along the back and neck — the "sandpaper back" appearance. Causes include flea allergy (most common), food allergy, atopic dermatitis, cheyletiellosis, and ringworm
- Eosinophilic plaque: Raised, moist, intensely pruritic plaques most commonly on the abdomen or inner thighs; often eosinophilic infiltrate on biopsy; associated with allergy
- Indolent ulcer (rodent ulcer): Raised, well-demarcated upper lip ulcer; usually not painful despite alarming appearance; allergy or immune-mediated
- Symmetrical alopecia: Bilateral hair loss from overgrooming in anxious or pruritic cats — stress and allergy both causes
Causes and Diagnosis
A systematic diagnostic approach:
- Exclude ectoparasites first — comprehensive flea control, Demodex and Cheyletiella skin scrapes
- Dietary exclusion trial — 8–12 weeks on strict hydrolysed or novel protein diet to exclude food allergy
- If dietary trial negative: consider atopic dermatitis — intradermal or serological allergy testing
- Skin biopsies and culture identify infectious causes or characterise inflammatory infiltrate
Treatment
Corticosteroids: Highly effective for allergic skin disease; prednisolone or dexamethasone. Cats tolerate steroids better than dogs but long-term use increases diabetes and infection risk.
Ciclosporin: Licensed for cats; slower onset than steroids but reduced long-term side effect profile; useful for chronic management.
Oclacitinib: Not currently licensed for cats but shows promise in early studies.
ASIT (allergen-specific immunotherapy): Available for atopic cats identified through allergy testing; the most welfare-positive long-term approach.
Welfare Significance
Chronic pruritus causes significant suffering in cats — overgrooming, self-excoriation, and behavioural changes from persistent discomfort all reduce quality of life. The tendency to attribute hair loss to "stress" without investigating medical causes delays appropriate treatment. Any cat with chronic skin changes or hair loss should receive thorough veterinary investigation.