An unresponsive progressive pustular and crusting dermatitis with acantholysis in nine cats

Area of Science:

• Veterinary Dermatology
• Comparative Pathology

Background:

• A retrospective study documented a distinct crusting dermatitis in nine cats observed between 2000 and 2012.
• The condition presented as a progressive, crusting dermatitis with variable pruritus, poorly responsive to conventional therapies.

Observation:

• The affected cats, ranging from two to eight years old, predominantly included neutered males and resided in Northern California.
• Clinical signs included well-demarcated crusting and pruritus, persisting for extended durations (1.5 months to five years).

Findings:

• Histopathology revealed parakeratotic and orthokeratotic crusts, intraepidermal pustules, superficial folliculitis, and acantholytic cells.
• Bacterial (Staphylococcus pseudintermedius) and fungal (Trichophyton terrestre, Malassezia pachydermatis) cultures yielded limited significant findings.
• Therapeutic interventions, including antibiotics, antifungals, and immunosuppressants, failed to alter the disease's progressive course.

Implications:

• This acantholytic dermatitis shares features with pemphigus foliaceus but is distinguished by its treatment resistance and progressive nature.
• The etiology of this feline skin condition remains undetermined, warranting further investigation.