Page 191 - Canine Lameness

12.8 ­ onDcD oe ofsctrs­alrawe 163

reinjury because the healed tissue lacks the pliability and durability of the uninjured tissue.
Unattended lesions that produce excessive granulation tissue leading to large fibrous scars and
exaggerated cicatricial contraction may deform the interdigital skin, making it less distensible and
interfere with individual digit movement. This interdigital deformation may itself result in lame-
ness. Radiographs and ultrasound might be helpful to detect underlying bone involvement and to DISTAL LIMB REGION
locate foreign bodies.

12.7.2 Pododermatitis

Pododermatitis (Figure 12.10a) is a nonspecific term to describe several inflammatory conditions
that affect the skin of the paws (Breathnach et al. 2008; Duclos 2013). There are multiple causes for
the condition: allergic dermatitis, foreign bodies, mechanical or chemical trauma, fungal and para-
sitic infections, in addition to psychogenic or idiopathic sterile pyogranulomas. Bacterial infection
is usually secondary. Tissues that may be affected include the interdigital skin, paw pads, nails, and
nail folds. Clinical signs include pruritus, edema, swelling, erythema, alopecia, paronychia, detach-
ing or detached claws, and serous, hemorrhagic, or purulent discharge. A single, or multiple, digits
or feet may be affected, and the degree of lameness varies.

12.7.3 Acral Lick Dermatitis
Acral lick dermatitis (or acral lick furunculosis/granuloma) is a condition characterized by excessive
licking of the distal limb region of the front limbs, although the pelvic limbs may be affected occa-
sionally (Shumaker 2019). The condition has multiple causes and may be precipitated by allergies,
behavioral, or underlying orthopedic conditions that cause pruritus or pain. Occasionally a tumor,
foreign body (Figure 12.10b), injury, or opportunistic fungal infection may be the inciting cause. The
condition is often associated with a deep staphylococcal and/or mixed bacterial infection, either pri-
marily, or through secondary invasion. The Doberman Pinscher, German Shepherd Dog, Golden and
Labrador Retrievers, Great Dane, Weimaraner, and Irish setters are reported to be predisposed.
Incessant licking produces lesions which appear as firm, raised, erythematous, and erosive plaques
initially. With chronicity, these become more extensive, thickened, hairless, hyperpigmented, and
ulcerated with scattered furuncles which erode and weep exudate. Diagnosis is generally confirmed
by clinical appearance (Figure 12.10c). Radiography is indicated to identify underlying bone reaction
and involvement, as well as to establish an underlying cause for the licking (e.g. joint disease). Tissue
culture is recommended in severe cases for assessment and treatment of deep bacterial, or rarely,
fungal infection. Treatment is aimed at identifying the underlying disease, treating the primary dis-
ease (if possible) as well as the secondary infection (if present), and stopping the licking behavior
(Shumaker 2019).

12.8 Conditions of the Claws

Conditions of the claws are easily overlooked and often subtle, but they can be the primary cause
of lameness (Mueller 1999). Excessively long claws may predispose animals to claw, digital, and
musculotendinous injury as well as pododermatitis, all of which may lead to lameness. In addition,
abnormal nail wear may indicate other conditions causing a lameness. For example, causes of
excessively short nails due to abnormal wear include neurological conditions causing loss of con-
scious proprioception, conditions which cause abnormal foot carriage (e.g. dorsal curvature of the
radius due to premature closure of the distal ulna growth plate), and conditions which cause the
animal to “drag” its feet during the swing phase (e.g. severe bilateral, painful osteoarthritis of the