228 DISEASES/DISORDERS
Self-injurious (especially oral) behaviors may be a coping mechanism to reduce emo-
tional arousal; the initial stimulus may produce a ritualistic behavior that persists
outside the original context.Neuro-immuno-cutaneous-endocrine (NICE) model: recognizes the interactions
between body systems for both the production of and management of various der-
matoses.Stress-vulnerable pathways trigger the release of neuropeptides and cytokines that
mediate behavior (scratching, biting, licking) and contribute to increased sensation
(pain, pruritus) through histamine release, central lowering of the itch threshold,
vasodilation, and immunologic reactions.The resulting excoriation releases mediators of inflammation and endogenous opioids
and may become a conditioned response.
Serotonin activity has been postulated as a specific effector of compulsive disorders.
Factors involved in the etiology of psychodermatoses include breed (emotional or
nervous), lifestyle (stressful, boring, isolating), and individual personality (anxious,
fearful).Occasionally, the owner may be able to correlate a specific physical (injury) or emo-
tional event just before the onset of symptoms.
Psychodermatoses primarily include acral lick dermatitis, feline symmetric alopecia,
flank sucking, tail biting or chasing, and anal licking.
The primary role of physical versus psychogenic cause is controversial, especially
with acral lick dermatitis.
SIGNALMENT/HISTORY
Acral lick dermatitis: generally younger age of onset (variable 1–12 years); no sex pre-
dilection; common in large breed dogs: Labrador and golden retriever, English and
Irish setter, dalmatian, doberman pinscher, Great Dane, Akita, shar-pei, boxer, weima-
raner; primarily of psychogenic origin in the Great Dane and doberman pinscher.Feline symmetric alopecia: variable age of onset; no sex predilection; possibly more
common in Siamese, Abyssinian, and oriental breeds; majority of cases seen in indoor-
only, multi-cat households.Flank sucking: variable age of onset; no sex predilection; seen primarily in the dober-
man pinscher.
Tail biting or chasing: young (socially mature) dogs and cats; neutered males; long-
tailed or herding breeds, predominantly German shepherd dog, Australian cattle dog,
Staffordshire and English bull terrier.Anal licking: young (socially mature) dogs; predominantly poodle.
CLINICAL FEATURES
Acral lick dermatitis (Figures 14.1–14.3):
Compulsive licking of the distal extremity: most often carpus or metacarpus;
less commonly radius, tibia, tarsus or metatarsus