Perianal skin disease

Question 1

What animals are anal sacs found in what is their function?

Answer 1

*Function = scent marking
*Seen in carnivores + many other mammals

Question 2

What are the length of the anal sac ducts + where do they open?

Answer 2

*3-10mm long
*Open at anal mucocutaneous junction at 4 + 8 o’clock

Question 3

Impaction is a common problem what are the clinical signs?

Answer 3

• Recurrent pruritus (scooting, rubbing and biting – local and more widespread
  i.e. tail head, inguinum or lateral thighs)
• Pain and depression
• Distended anal sacs
• Malodour

Question 4

What are the primary causes of anal sac impaction?

Answer 4

• Abnormal character and volume of secretion
• Change in muscle tone
• Faecal form – diarrhoea or constipation
• Plugging of the ducts

Question 5

What are secondary causes of anal sac impaction?

Answer 5

*Bacterial infection
*Rarely - Malassezia overgrowth

Question 6

What are predisposing factors of impaction?

Answer 6

*Inflammatory skin disease
*Breed - some breeds = prone to impaction
*Obesity

Question 7

What are differential diagnoses for anal sac impaction considering perianal pruritus?

Answer 7

• Allergic skin disease (especially CAD)
• Endoparasites
• Severe flea infestation
• Vulval fold dermatitis
• Tail fold dermatitis

Question 8

What are differential diagnoses for impaction considering abscessation?

Answer 8

*Anal furunculosis

Question 9

What are differential diagnoses for impaction considering nodules / palpable glands?

Answer 9

Anal sac adenocarcinoma

Question 10

How is impaction diagnosed?

Answer 10

*Palpation + expression of sacs
*Cytology of anal sac fluid
*Culture + susceptibility testing

Question 11

What is the treatment of recurrent anal sac impaction?

Answer 11

*expression
*addition of fibre to food to improve faecal consistency
*Short course prednisolone
*Flush + pack
*Anal sacculectomy for recurrent cases

Question 12

How would you treat anal sac infection?

Answer 12

*Repeat emptying + topical antibiotics as for impaction
*AVOID systemic antibiotics

Question 13

How would you treat anal sac abscessation?

Answer 13

*Local cleaning - chlorohexidine shampoo
*Systemic antibiotics to treat infection of soft tissues
*Consider prednisolone to reduce inflammation once infection tx started
*Analgesia - NSAIDs / paracetamol

Question 14

What are the clinical signs of anal sac adenocarcinoma?

Answer 14

*No clinical signs unless detected on palpation
*Some cases = paraneoplastic disease = Polydipsia / polyuria w hypercalcaemia + secondary renal disease

Question 15

Does metastasis often occur? If so where?

Answer 15

Yes - sublumbar + iliac lymph nodes

Question 16

What is the median survival time of anal sac adenocarcinoma?

Answer 16

18months

Question 17

What are predisposing factors of anal furunculosis?

Answer 17

Genetic predisposition
usually seen is german shepherds

Question 18

What is the pathogenesis of anal furunculosis?

Answer 18

May involve inappropriate response to bacteria around the anus

Question 19

What are the clinical signs of Anal furunculosis?

Answer 19

• Tissue destruction and sinus formation
• Huge ulcerative tissue deficits in chronically affected cases
• Moderate to severe pain – care when examining
• Difficulty in passing faeces and faecal incontinence

Question 20

How is anal furunculosis diagnosed?

Answer 20

*Clinical signs in predisposed breeds
*Elimination of other causes of perianal sinus formation
*Cytology to assess presence of bacterial infection

Question 21

What is the treatment of anal furunculosis?

Answer 21

IMMUNOMODULATORY THERAPY
*Ciclosporin (best option)
*Tacrolimus
*Prednisolone +/- azathioprine

other=
*Manage bacterial overgrowth
*Analgesia
*Surgery
-most cases need life long therapy