Acral lick dermatitis

45 Acral lick dermatitis




INITIAL PRESENTATION


Swelling with eroded surface on the distal forelimb.



INTRODUCTION


Canine acral lick dermatitis is a condition characterized by a firm, alopecic, frequently ulcerated plaque on a distal limb or limbs, caused by licking and usually complicated by a secondary bacterial infection. It used to be considered that the licking was purely the result of a psychogenic disorder, but it is now known that in many cases it is caused by a variety of pruritic or painful organic diseases, sometimes with a psychogenic component. This report describes a case of acral lick dermatitis in a Labrador.




CASE PRESENTING SIGNS


A 6-year-old, neutered male Labrador was presented with a swelling over the left forelimb.



CASE HISTORY


A detailed history and full physical and dermatological examinations should help the clinician in determining whether the licking is the result of underlying organic disease, a psychogenic disorder or a combination of the two. The history should ascertain whether the skin disease is confined to the limb or whether there is, or ever has been, evidence of a more generalized skin problem. It is also important to establish the presence or absence of lameness in the affected limb, or previous injury.


The relevant history in this case was:


• There was no history of other skin disease or more generalized pruritus.

• There was no history of systemic illness, pain, lameness or previous injury.

• Nine months previously, the dog had started to lick the left forelimb and, despite topical antibacterial and glucocorticoid therapy (sodium fusidate and betamethasone), the licking had persisted, resulting in two eroded and exudative plaques.

• A similar lesion had developed 3 years previously that had resolved with the above therapy.

• The licking behaviour would not occur when the dog was being observed. It had become evident that licking occurred whenever the dog was left unattended.

• An Elizabethan collar was used at night to prevent further self-trauma.

• There was one other dog in the household, a male sibling that was unaffected.

• There was no evidence of zoonosis.

• Both owners worked full time. They had moved house two and a half years previously. Prior to that, one or other of them had been able to return home during the day to exercise the dogs, but this had not been possible since the move. The dogs were in a kennel with a dog flap and a large outside run from 7.30 a.m. until 6.00.p.m. 5 days a week.

• Routine flea control consisted of monthly applications of fipronil spot-on during the summer and every 6–8 weeks during the winter.

• The diet consisted of a proprietary tinned and dried food, occasional bones and just water to drink.


CLINICAL EXAMINATION


Acral lick dermatitis usually develops on the limbs at the level of, or distal to, the mid radius or tibia. The anterior aspect of the carpus is commonly affected. Lesions may be single or multiple. The typical lesion is a raised, alopecic plaque with an eroded or ulcerated area at the centre of the lesion and a hyperpigmented margin. Some lesions may have draining sinus tracts and this should alert the clinician to the possibility of deep bacterial or fungal infection. There may be evidence of more generalized skin disease, such as otitis externa or pyoderma.


The examination should include manipulation of local joints and the neck (to assess for cervical pain), and palpation of underlying bone. If there is evidence of orthopaedic or generalized skin disease, these symptoms should be investigated and treated accordingly.



• No abnormalities were detected on full physical examination.

• There was no lameness and no pain on manipulation of the carpal joint.

• There were two eroded and slightly exudative plaques over the lateral aspect of the left carpus (Fig. 45.1).

• Apart from moderate erythema of both external ear canals, there were no other skin lesions.

image

Figure 45.1 Case of acral lick dermatitis at initial presentation. Two eroded and slightly exudative plaques over the lateral aspect of the left carpus.




DIFFERENTIAL DIAGNOSES


There are focal inflammatory, or neoplastic, disorders which may resemble acral lick dermatitis and that result in licking. In this case, there was evidence of aural erythema, which might have been evidence of a hypersensitivity disorder. The differential diagnoses included:



• Acral lick dermatitis

• Deep bacterial or fungal granuloma

• Demodicosis

• Histiocytoma

• Mast cell tumour

• Other cutaneous neoplastic disease

• Underlying allergic dermatitis (atopy or adverse food reaction)

• Underlying hypothyroidism.

Related posts:

  1. Cheyletiellosis in a rabbit
  2. Metabolic epidermal necrosis
  3. Demodicosis
  4. Digital squamous cell carcinoma

Stay updated, free articles. Join our Telegram channel
Tags:
Sep 3, 2016 | Posted by in SMALL ANIMAL | Comments Off on Acral lick dermatitis

Full access? Get Clinical Tree
Get Clinical Tree app for offline access