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It's not magic: The skinny on treating canine atopic dermatitis

By Darin Dell, DVM, DACVD

Red, itchy skin is more than just an annoying problem. It negatively affects a dog’s quality of life and can lead to secondary infections. Fortunately, this overview of your therapeutic options and step-by-step treatment strategy can help you provide relief to your itchy patients—and as a bonus, this veterinary dermatologist throws in a few treatment tricks of the trade.

Canine atopic dermatitis is like a trickster in a fairy tale — always causing chaos. But let's talk about a more practical kind of magic. After all, you don't need to be Houdini to get pet owners to cheer for your successful treatment of their itchy pets. It is true that an estimated 10% to 15% of dogs suffer from atopic dermatitis; and the actual number is probably considerably higher. Atopic dermatitis typically manifests as pruritus and erythema, but some dogs develop recurrent pyoderma or otitis externa instead.

Here's how to take the intrigue out of canine atopic dermatitis—no secret key or sleight of hand required. We're talking about a long-term relationship here!

Dr. Darin Dell explains the importance of a supportive relationship with owners of atopic dogs and of asking what they can handle —you're in it for the long haul!

No Magic Pill

No single therapy is 100% effective at treating atopic dermatitis. Most patients need a core therapy and one or two supportive therapies. Four core allergy therapies that are safe for long-term use are 1) immunotherapy, 2) cyclosporine, 3) oclacitinib and 4) canine atopic dermatitis immunotherapeutic (CADI).

Immunotherapy

Immunotherapy, the gold standard of allergy therapy, is the only treatment that changes the immune system’s response to allergies rather than suppressing the immune system or dulling the clinical signs. Immunotherapy can prevent new allergies from developing. It is also the only therapy that could potentially cure a patient. However, the cure rate is low, and most dogs require immunotherapy for life.1

• Onset of action: Six to 12 months for significant benefit
• Side effects: No major side effects (anaphylaxis can occur but is rare)

Tips

• Both administration routes (subcutaneous injections and sublingual drops) are effective. The best choice is the one that the owner will comply with.

• Because of the slow onset of action, many patients need an additional core therapy when beginning immunotherapy.

• Dogs should receive immunotherapy for a year before you and the owner discuss whether it is worth continuing.

Cyclosporine

Cyclosporine (Atopica—Elanco) treats allergy signs by suppressing IL-2, T helper cells, and T suppressor cells.2

Onset of action: Four to six weeks for full effect

Side effects: Mild vomiting and diarrhea are the most common. Hypertrichosis, gingival hyperplasia or immunosuppression is possible.

Tips

• To help prevent vomiting, owners can freeze capsules, give the medication with a small meal, divide the dose throughout the day, or start with a low dose and ramp up to the target dose over two weeks.

• Since cyclosporine does not provide immediate relief. I combine it with a corticosteroid during the first two or three weeks of treatment.3

• Do not taper cyclosporine until the desired response has been reached. It is best to taper slowly by eliminating one dose a week until every-other-day dosage is achieved or clinical signs relapse. If a relapse occurs, the client should return to the previously effective dosing regimen. An inability to taper does not indicate treatment failure; some dogs require daily therapy long term.

A Magical(ish) Treatment Strategy:

Every allergen patient is different—different allergies, primary signs, and secondary problems—so every treatment needs to be different, too. Nevertheless, your treatment strategy should be consistent.

Step 1. Provide adequate flea control. Any allergy (e.g. flea, food, seasonal) can cause other allergies to get worse—it can kick start inflammation. So ensure that fleas are a nonissue by making sure these dogs are receiving appropriate flea control.

Step 2. Eliminate infections. Eliminating infections reduces pruritus and inflammation while also improving the patient’s odor and appearance. Dogs with allergies may be slower to respond to antibiotics than dogs without allergies are, so check progress after three weeks of antibiotic therapy but treat until infections are gone.

Step 3. Rebuild the epidermal barrier with ceramides. When the epidermal barrier is intact, there is less allergen exposure, less risk of infection and less pruritus. You can find ceramides in shampoos, sprays, conditioners and spot-on products.

Step 4. Conscientiously choose a core treatment. First and foremost, the best treatment is the one that the owner will actually administer correctly. Beyond that, consider the patient’s underlying medical conditions, the severity of the allergy, and the primary signs.

Step 5. Add supportive therapy as needed. These therapies include antibacterial and antipruritic shampoos, wipes and sprays as well as oral antihistamines, oral essential fatty acids and topical ceramides. Reevaluate your supportive therapy after a month and then on an on-going basis, as the patient’s needs will likely change over time.

References

1. Dell L. Darin, Griffin CE, Thompson LA, et al. Owner assessment of therapeutic interventions for canine atopic dermatitis: a long-term retrospective analysis. Vet Dermatol 2012;23:228.

2. Guaguere E, Steffan J, Olivry T. Cyclosporin A: a new drug in the field of canine dermatology. Vet Dermatol 2004;15:61-74.

3. Dip R, Carmichael J, Letellier I, et al. Concurrent short-term use of prednisolone with cyclosporine A accelerates pruritus reduction and improvement in clinical scoring in dogs with atopic dermatitis. BMC Vet Res 2013;9:173.

4. Cosgrove SB, Wren JA, Cleaver DM, et al. A blinded, randomized, placebo-controlled trial of the efficacy and safety of the Janus kinase inhibitor oclacitinib (Apoquel) in client-owned dogs with atopic dermatitis. Vet Dermatol 2013;24,587-597.

5. Zoetis, Apoquel package insert, February 2013.