Itchy skin

ITCHY SKIN (PRURITIC DERMATITIS)
NON-SPECIFIC
DIAGNOSIS
SPECIFIC THERAPY
- Doramectin weekly - Amitraz twice weekly -Prescription Diet Canine/Feline z/d Low Allergen Steven Metcalfe, APPLECROSS VETERINARY HOSPITAL Page 1 3 September 2013 Staphylococcus
intermedius
Malassezia
pachydermatis

Work-up proposal for the itchy dog: Visit 1
1.Multiple superficial and deep skin scrapings
2.If negative then use Revolution for three treatments two weeks apart
3.Do cytology on any greasy skin surface with tape strip impression smears to look for
a asse ia organisms
4.If present then treat with topical Malaseb shampoo twice a week and ketoconazole 5
to 10mg/kg/bwt daily for four weeks
5.If papules, scaling, pustules, epidermal collarettes are present then do skin surface
cytology with either direct impression smear or tape strip
6.If present then treat with topical Pyohex shampoo twice a week and cephalexin
20mg/kg/bwt twice daily for four weeks
7.Begin an elimination diet trial using either Hills z/d ultra or a novel source of protein
and carbohydrate for four weeks
8.Withdraw corticosteroids
9.Revisit at 4 weeks….refer for intradermal allergy testing

Steven Metcalfe, APPLECROSS VETERINARY HOSPITAL Page 2 3 September 2013 Diagnostic testing for food hypersensitivity
Elimination diet
Definitive diagnosis of food hypersensitivity in dogs and cats is made only on the basis of elimination Length of diet trial
The necessary duration of the elimination diet as a diagnostic test is controversial. Most dermatologists believe that some improvement should occur within 4 to 6 weeks.
Constituents of elimination diet
Hypoallergenic diets must be individualised for each patient, on the basis of careful dietary history. The primary objective is to select a food combination that has minimal or no history of previous
exposure.
There is no single ideal elimination diet for all dogs with suspected food allergy; possible options for protein include kangaroo, horse, donkey, goat, fish, turkey, duck, venison, emu, rabbit and
possible options for carbohydrate include potato, sweet potato, beans or barley.
Feeding a strict diet is essential; make sure to exclude rawhide chews, flavoured dietary supplements;
beef flavoured heart worm prophylaxis etc. CATS

In Australia, the commonly fed commercial foods contain beef, lamb, chicken, fish and wheat. We tend
to base our elimination diets on kangaroo, horse, goat, deer, rabbit, pork or baby food (turkey,
ham). We do not use a carbohydrate source such as potato or rice, as is employed in the dog, as this is
often unpalatable for the cat. In many cases to adequately perform the dietary trial the cat may need to Is it balanced?
The diet is not complete and balanced and is not meant to be so. It is meant to give the animal something to eat during the test period. Occurrence of overt signs of vitamin, mineral or taurine deficiencies after the short period of the test would be rare. Steven Metcalfe, APPLECROSS VETERINARY HOSPITAL Page 3 3 September 2013 What about commercial limited protein source diets?
If the owner is either unwilling or unable to home cook, commercial diets are available that are unique in their primary ingredients. A commercially prepared limited novel protein source diet offers an alternative to a home prepared elimination diet but is not considered to be as accurate. It is critical to understand that the reliability of most these commercial diets has either not been confirmed or confirmed in limited trials only. For your interest
When known food hypersensitive dogs were fed canned d/d and dry d/d (Hill’s Pet Products), 15 to 25% became pruritic again (Roudebush 1994). A study with fish and potato (Iams FP Response) indicated that 50% of previously confirmed food allergic dogs were more pruritic on this product and in 25% of dogs the worsening of clinical signs was confirmed to be due to the fish (Tapp 1999) More Interesting facts
None of these diets has been scientifically evaluated in confirmed food-hypersensitive cats. Only one commercial diet has been evaluated in cats; feline d/d (Hills) and about 20% of cats became pruritic What about the new hydrolysate diets?
Newer hypoallergenic diets have been formulated utilising hydrolysed proteins in an attempt to supply an adequate protein source that is not capable of inciting food hypersensitivity. CNM-HA (Purina)
utilises hydrolysed soybean protein and corn starch and Hill’s z/d Ultra utilises hydrolysed chicken
and starch. Although limited studies by the companies that have developed these diets suggest they may be beneficial, further independent studies are required. Assessing response to diet
The major clinical sign being evaluated during the elimination diet is the pruritus. The level of pruritus should markedly decrease, but this may be gradual and may take 4 to 8 weeks to become evident.
As up to 75% of food hypersensitive dogs have other concurrent hypersensitivities (insect, atopy), the response to a hypoallergenic diet may be partial. Steven Metcalfe, APPLECROSS VETERINARY HOSPITAL Page 4 3 September 2013 Confirming food allergy
A presumptive diagnosis of food allergy can be made if the dog or cat responds to the elimination diet. Confirmation of a cause and effect relationship between food and a set of symptoms is still dependent upon provocative challenge. Provocation testing is achieved by feeding a test meal of the dog’s or cat’s previous diet. If no relapse is seen, treats are introduced. Sequential rechallenge
Involves feeding each of the major food items that were contained in the original diet reported to cause food hypersensitivity in dogs (beef, dairy products, wheat, soy, chicken, lamb, pork, eggs, corn) or cats (beef, dairy products, fish, chicken, lamb) by adding one pure food ingredient to the restrictive diet to determine which individual allergen or allergens is incriminated. Almost all adverse reactions will occur within 7 days. Rarely up to 14 days of exposure to the offending ingredient may be necessary. Steven Metcalfe, APPLECROSS VETERINARY HOSPITAL Page 5 3 September 2013 CANINE ATOPIC DISEASE

WHAT IS ATOPY?
Atopy is a common skin disease causing itchiness in the dog. It is a reaction by an individual animal’s
body to inhaled airborne pollens from grasses, weeds trees, mould spores and house dust. Most dogs
develop atopy as young adults ie between one and three years of age. The most common clinical sign is
itching, usually involving the muzzle, around the eyes, ear flaps, armpits, groin and paws. Some dogs
may have recurrent ear infections. As a result of chewing, licking, rubbing and scratching, the skin
becomes inflamed and is prone to secondary infections with bacteria and yeast. In dogs with chronic
disease, there is hair loss and the skin often becomes thickened scaly and black. The hair coat may feel
greasy and be associated with an offensive odour.

HOW IS IT DIAGNOSED?
Atopy is diagnosed by performing an intradermal skin test on your dog. This involves clipping a patch
of hair from the side of the flank and pricking the skin with tiny amounts of purified extracts of
relevant grass, weed and tree pollens, mould spores and house dust. A positive reaction is a raised, red
swelling observed thirty minutes after the injection. Many drugs including antihistamines and
corticosteroids affect the skin test. As all cortisone injections, tablets, lotions and eye and ear drops
interfere with the intradermal skin test, it is important that your pet is withdrawn from treatment prior
to testing.

HOW CAN ATOPY BE TREATED?
There are several ways that atopy can be managed in order to keep your dog comfortable. Therapy can
involve a combination of these alternatives.

1. AVOIDANCE
Unfortunately, avoidance of grass and weed pollen and house dust is virtually impossible. These
substances are airborne and in the case of pollens, may travel considerable distances. In some instances,
dogs with house dust allergy may benefit from being kept outdoors.

2. HYPOSENSITISATION
This involves desensitising your pet to things that it is allergic to through a course of injections with
purified extracts. It is considered the best treatment for atopy in the dog. There is more detail about
hyposensitisation in the information sheet. It is important to realise that the improvement with allergy
vaccines is gradual, with obvious benefits taking from between two and six months to appear. While
allergy vaccines considerably help some 70% of dogs, there are a percentage of dogs (approximately
30%) in which the vaccine is less effective.

3. MEDICAL THERAPY
While your dog is receiving an allergy vaccine, or alternatively, if you have elected not to pursue
hyposensitisation, medical therapy is required to control the itching. The most useful agents to control
allergy are cortisone-based drugs. Unfortunately, these can be associated with undesirable side effects.
Common side effects include increased thirst, urination and appetite, weight gain and panting. In the
long term, cortisone can be associated with infections, liver disease, pancreatitis and gastrointestinal
ulceration. They are, therefore, not satisfactory for long term usage in controlling allergy. Other medical
options include antihistamines and fatty acid supplementation that can help relieve itching but rarely
control the signs completely.

4. TOPICAL THERAPY
Frequent shampooing of your dog will help remove pollen from the coat, surface debris, and bacteria
and help soothe the skin. We generally recommend that your dog be bathed once a week. Topical
Steven Metcalfe, APPLECROSS VETERINARY HOSPITAL Page 6 3 September 2013 cortisone lotion or ointment can be used if only localised areas ie. paws, ears or around the eyes are
affected.

5. FLEA CONTOL
It is important to use a thorough flea control in your atopic pet, even if your pet is not allergic to flea bites, the presence of fleas may aggravate his/her underlying allergy. We recommend the weekly use of Permoxin flea rinse applied after bathing, in conjunction with appropriate environmental flea control measures. Grass P
e s
Mould Spores
Weed Pollens
House Dust Mite
Tree Pollens
Miscellaneous
ew P
e s
Steven Metcalfe, APPLECROSS VETERINARY HOSPITAL Page 7 3 September 2013 Steven Metcalfe, APPLECROSS VETERINARY HOSPITAL Page 8 3 September 2013

Source: http://www.applecrossvet.com.au/Portals/applecrossvet/ITCHY%20SKIN_1.pdf