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An Urban Experience
supplements are reported to reduce pruritus in 20% to 30% of atopic dogs. Recently, several topical lipid/ fatty acid preparations have become available that claim to aid in normalizing the skin barrier. Small studies show some effectiveness in restoring the skin barrier and reducing pruritus and inflammation with these products, but larger comparative studies are needed to determine the most effective products, optimal frequency, preferred application technique, and best case selection. A 1-2 month trial is needed to judge efficacy. At the very least, these products are very safe and should result in less odor and a shinier hair coat.
In several evidence-based reviews of treatments for
AD, antihistamines have not demonstrated efficacy. Veterinarians continue to try various products approved for use in humans at various doses with the belief that they are safe and inexpensive and that they may, in some cases, provide relief from pruritus in allergic dogs; but
the best that can be shown is that ~20% of dogs are benefited, which is comparable to placebo. Even the belief that they may cause sedation, which would help with pruritus, has not been shown. This is why there is no veterinary-approved antihistamine for the treatment of pruritus.
Glucocorticoids historically are the mainstay of effective treatment of pruritus and allergic skin disease. In many cases the side effects outweigh the benefits. The goal
is to use oral prednisone or prednisolone at the lowest possible dose (“comfortably itchy”). A proposed “safe annual steroid dose” has been published: 15 x weight in lbs = mg prednisolone/ year and can be used as a guide for dogs being managed with long-term glucocorticoid therapy. The use of long-acting injectable glucocorticoids should be avoided in the long-term management of canine allergic skin disease.
Ciclosporin is a calcineurin inhibitor that is effective as
a steroid alternative for treatment of canine AD. It blocks activation of T-cells and the cytokines they produce
that are involved in the allergic response reducing inflammation and pruritus. Studies have shown that the signs of canine AD can be well controlled with the use of ciclosporin, 5 mg/kg q 24 hours in approximately 50-70 % of cases with increasing percentages with longer term use. Atopica® is the veterinary form of ciclosporin and is preferred over generics. The dose is 5 mg/kg once daily. Major advantages include the lack of steroid-related side-effects such as polyuria, polydipsia, weight gain, muscle weakness and personality changes. The drug is not fast acting and may take 3-6 weeks for efficacy to be seen, so is often combined with low dose corticosteroids or oclacitinib for the first 2-3 weeks. Gastrointestinal
side effects occur in approximately 15-25 % of cases, but are usually self-limiting and can be minimized by slowly building up to the full dose over 10-14 days, pre- treating with an anti-emetic 2 hours before ciclosporin
for the first 10 days, and giving medication with a
small amount of food. Other less common side-effects include papillomatosis, hirsutism, gingival hyperplasia, tremors/ neuropathies, secondary pyoderma,
and lymphoplasmacytic dermatitis. Occasional hypoalbuminemia, urinary tract infections and increased liver enzymes may be seen. Ciclosporin does not interfere with serum or intradermal allergy testing. The major disadvantage to the use of this drug is the cost, but this can be lessened with every other day or half dose daily therapy, which can be attained in 40-50 % of cases.
Oclacitinib (Apoquel®) has been approved for the control of pruritus associated with allergic dermatitis and for the control of atopic dermatitis in dogs 12 months
of age or older. It is a novel, targeted, oral Janus kinase (JAK) enzyme inhibitor that inhibits the action of many allergic cytokines, including interleukin (IL)-31, which use the JAK STAT pathway for cell signaling. Studies have shown it is effective and safe in controlling pruritus associated with canine allergic dermatitis and atopic dermatitis. In laboratory studies, it is more rapid-acting (within 1 hour) than oral prednisolone or dexamethasone injections without steroid-related side-effects. The approved dose is 0.4-0.6 mg/kg PO bid up to 14 days then once daily for maintenance therapy. Apoquel has been safely used in conjunction with other common medications including antibiotics and parasiticides and with vaccinations. It does not interfere with serum or intradermal allergy testing.
Allergen-specific immunotherapy is the only treatment that may prevent the progression of AD
or result in a cure in some cases. Immunotherapy
is thought to normalize the immune response by increased production of T regulatory cells and anti- inflammatory cytokines that reduce the Th2 inflammatory cascade. Once a clinical diagnosis of AD is made,
the dog can be tested for the presence of allergen- specific IgE antibodies to select allergens to include in the allergen-specific immunotherapy (ASIT) vaccine.
The currently available tests include the intradermal
test (IDT) and allergen-specific IgE serology (ASIgES)
for measurement of allergen-specific IgE. It seems that no matter which test is performed to select allergens (serologic or intradermal), published reports show that about 60-70% of dogs with AD show at least a 50% improvement of their AD when treated with ASIT when “micro-managed” by a dermatologist. Most dermatologists recommend that injections be given once weekly, after the initial induction schedule is followed, for 1 year before a final assessment of response is made in order to maximize the chance of success. Many atopic dogs still require treatment of acute flares in pruritus
with oral and/or topical anti-pruritic medications, but the frequency of medications can often be reduced. The dose and frequency of ASIT injections often needs to be

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