Mutually‐induced traumatic alopecia responsive to husbandry modification in two cohabiting donkeys

Abstract

SummaryCutaneous expression of behavioural processes remains unexplored in donkeys. This case report describes a case of traumatic alopecia in two donkeys secondary to mutual hair plucking behaviour. Two genetically unrelated, male castrated, 4‐year‐old Cotentin donkeys living together were presented for a 2‐year history of alopecic, mainly nummular, nonpruritic lesions developing on the back, loin and croup. The general physical examination and behavioural assessment were unremarkable. Trichoscopy, scrapings and cytology were performed. Superficial bacterial infection was diagnosed but a 2‐week course of antibacterial treatment showed no improvement. Histopathological examination showed features compatible with traumatic alopecia and consistent with several behavioural causes of alopecia resembling human trichotillomania or acute traction alopecia, canine traction alopecia, feline self‐induced alopecia and murine barbering. Separation of the donkeys led to complete long‐term remission. Clinical and histopathological findings in our case share lots of similar features with the different mechanical traumatic alopecic disorders mentioned above, making it impossible to simply classify the described affection. Whether alopecic lesions resulted from an exclusive behavioural process (either abnormal excessive mutual grooming or other social interactions) or were associated with underlying causes of pruritus is uncertain. Mechanical alopecia secondary to a behavioural process should therefore be suspected in cases of permanent patchy alopecic nummular lesions on donkeys living in groups.