ACRAL LICK DERMATITIS
REFERS TO A SELF-INFLICTED
FOCAL LESION usually found
occurring on a distal (acral) extremity.
Favoured sites for the excessive
compulsive licking, which produces
the lesion, are most commonly on the
anterior carpal or metatarsal skin.
The problem tends to occur in
middle-aged to older breeds such as
the Doberman, Great Dane, Golden
Labrador, Labrador retriever, German
Boxer, although it
may occur in other
- Initially the lesion, in one of the
sites mentioned, tends to be quite
small but with increased licking slowly
- If untreated the lesion passes
through various stages (Hnilica, 2011).
Alopecia develops and the lesion
becomes firm, raised, thickened and
there is nodular ulceration, fibrosis
- Secondary infection at the later stage is
very common and is a deep pyoderma.
Untreated cases may progress to
- Damage to hair shafts due to the
licking may penetrate into the dermis
and will accentuate the deep pyoderma.
In one study, deep pyoderma was
present in 94% of acral lick lesions
(Shumaker and others, 2008).
- Whatever the initiating cause, the
problem can quickly become self-
perpetuating with the development of
an itch-lick cycle.
- Atopic dermatitis.
- Food hypersensitivity.
- Foreign body reaction.
- Deep pyoderma.
In addition to the diseases listed in the
differential diagnosis, many authorities suggest that a
major component in acral lick
although environmental stress may be a
factor, other causes are usually more
important (Hnilica, 2011) and these are
listed under the differential diagnosis.
It is suggested that differential
diagnosis rule-outs are investigated
before considering psychogenic
An additional complication is
that even if the original cause is
psychogenic, secondary infection is
very common and will need to be
treated before further evaluation. The
list of possible psychological causes
cited here has not changed from that
in previous editions of a standard text
in the last 20 years or so of previous
Possible psychological factors
(Miller, Grif n and Campbell, 2013)
- The dog is left alone all day.
- The dog is confined for long periods
to a crate, kennel, cage or run.
- There is a new pet in the home.
- A female dog is in heat nearby but not accessible to the dog.
- A new dog has come to the
- A death has occurred in the family.
- A long-time companion of the dog
- Children or other members of the
family have moved away.
- The history (breed predisposition,
licking) and clinical findings are very
- Investigation of underlying causes listed under differential diagnosis
- Biopsy for histopathological
examination. Biopsy may also be used
for bacterial culture as secondary
infection is likely to be deep. In these
cases, sterile preparation of the surface
- Histopathological findings are
often helpful in confirming the
diagnosis if doubt exists. Findings
include epidermal hyperplasia with
marked rete ridge formation, compact
orthokeratotic hyperkeratosis, which
strongly suggests chronic surface
irritation, and fibrosis of the dermal
- The orientation of the collagen
is perpendicular to the skin surface,
though not to the basement membrane
(Yager and Wilcock, 1994).
The treatment of the lesion will depend
on how long it has been present and
what stage has been reached.
Acral lick dermatitis has
multifactorial causes and some aspects
are still poorly understood. As a result
many treatments have been advocated.
In more advanced cases a collaboration
between dermatology and behavioural
specialists is more likely to be effective
than individual specialists alone.
For early mild lesions
- Topical glucocorticoids and
bandaging to prevent further trauma.
This is often not successful. Licking
elsewhere while a bandage is protecting
the lesion tends to suggest an
unresolved underlying psychological
- Sub-lesional injections of
glucocorticoids may break the itch-
lick cycle, but should not be used in
more chronic cases where secondary
pyoderma is a likely complication.
For chronic lesions
- Chronic lesions with secondary
deep pyoderma require long-term
antimicrobial systemic therapy based
on sterile deep biopsy sampling.
Treatment will be required for six to
eight weeks and as long as four to six months in severe cases (Hnilica, 2011). The predominant pathogen is
Staphylococcus pseudintermedius with some
strains having methicillin resistance
(Schumacher and others, 2008).
- Systemic therapy is continued until
the lesion clears and an assessment
is then made as to whether licking
remains a problem. Some cases will
clear up with long-term antimicrobial
therapy without relapsing. In those
that don’t, further investigations will be
necessary preferably in association with
a behavioural specialist.
- Surgical removal of the lesion is
possible with small lesions, but there
is a considerable risk of the dog
traumatising the wound and making the
situation much worse. It is generally not
Treatment with behaviour-modifying drugs
- Preferably, in those cases with identified
stress factors, behavioural therapy is the
optimal approach. Behaviour-modifying
drugs may be of short-term use in
conjunction with these cases and if no
obvious underlying psychological cause
is found may be useful as stand-alone
treatment. There are a number of drugs
reported to be of benefit (Hnilica,
- Anxiolytics (phenobarbital, diazepam,
- Tricyclic antidepressants
(fluoxetine, amitriptyline, imipramine,
- Endorphin blocker (naltrexone).
- Endorphin substitute (hydrocodone).
References and further reading
Hnilica, K. A. Small Animal Dermatology: A
Color Atlas and Therapeutic Guide; pp189-191.
Miller, W. H., Grif n, C. E. and Campbell,
K. L. Muller & Kirk’s Small Animal
Shumaker, A. K. and others (2008)
Microbiological and histopathological
features of canine acral lick dermatitis.
Veterinary Dermatology 19 (5): 288-298.
Yager, J. A. and Wilcock, B. P. Color Atlas and
Text of Surgical Pathology of the Dog and Cat
Dermatopathology and Skin Tumours, volume 1;
pp57-58. Wolfe, 1994.