Therapies to get patients through a tough allergy season - DVM
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Therapies to get patients through a tough allergy season


DVM360 MAGAZINE


With deep pyoderma that accompanies allergy, be sure to check skin scrapings so you don't miss demodex mites. Demodex mites can occur secondary to allergy and particularly in those patients kept on steroids for their allergy. Steroids are contraindicated in patients with demodicosis.

Anti-yeast medications

Since atopics not only have bacteria as an accompanying factor in allergy, yeast in some patients can be equally common. Since most atopics have ear involvement and lick their feet — two places where yeast is most-often found — it is important to check ear smears and nailbed/skin smears, especially of folded areas (axillae, groin, chin folds, nailbeds).

In some atopics, treating the accompanying yeast gives the pet a good deal of relief. Breeds that tend to have yeast as a primary factor or a complicating factor of atopy include Cocker Spaniels, Shih Tzus, Lhasa Apsos, Golden Retrievers, Labrador Retrievers, Basset Hounds, Beagles and Poodles.

In patients with facial pruritus, especially periocular lesions, be sure to check ear smears. When treating the yeast otitis with topical miconazole or clotrimazole, sometimes including a topical steroid for the localized yeast hypersensitivity that can occur, as well as antiyeast bathing in chlorhexidine, miconazole or benzyl peroxide can reduce pruritus.

Often, however, a systemic antiyeast medication such as ketoconazole 2.5-5mg/kg bid is helpful. A small percentage of humans taking ketoconazole develop elevated liver enzymes, but this occurs less frequently in dogs. Still, it is a good idea to monitor liver enzymes, particularly in patients on long-term maintenance doses (i.e., MWF or twice a week).

Many patients can be maintained even below published doses. The fact that the main adverse effect of ketoconazole in dogs is vomiting and diarrhea is good reason to start at a low dose and increase later if necessary.

Immunotherapy

Within the context of this article, immunotherapy refers to desensitization, hypo sensitization and allergy injections.

If you have a patient who is maintained on immunotherapy but flares during warm weather, schedule a recheck to rule out ecto parasites, bacterial infection and yeast infection.

Perhaps no lesions or ectoparasites are found, yet a once well-controlled dog has become pruritic. He/she may be getting too much antigen during the affected season. I often have the owner skip a dose of allergy injection and call me with the response. If the patient was less itchy without the injection, then I reduce the amount of the injection by 50 percent.

Conversely, if, when beginning injections, the patient is more pruritic after the injection, we will also skip a week and proceed at 50 percent of the dose the following week.

What we like to hear is that, after the injection, the patient is less itchy, then starts with pruritus as the next injection is due. In some patients where the injection seems to hold them for a few days, we will administer the injection twice during the injection period until we can get them stable.

In patients that are only outdoor-pollen allergic, I prefer to start immunotherapy in the late fall after the majority of their allergy season is over. It is too difficult to try and monitor their responses to the injections if you are administering what they are allergic to during their affected season.

Thyroid status

In some atopic patients, recurrent bacterial pyoderma is a symptom of underlying atopy but that can be true of hypothyroid patients too. I have had patients who responded well to immunotherapy, then became non-responsive once they became hypothyroid.

In middle-aged and older dogs that we are working up for atopy, checking for hypothyroidism is part of the workup. We check a T4 and if borderline, a FT4 TSH (15 percent to 30 percent of hypo thyroid patients can have a normal TSH). T4 values can be artificially reduced if the patient is receiving sulfas, NSAIDs, steroids or anticonvulsants, so be sure to take that into consideration. Some dermatologists believe patients with acral lick granulomas (also seen with atopy) can be hypo thyroid.

Fish-oil supplements

Much has been written on the potential benefits of fish-oil (omega 3, 6) supplementation. Omega 3 supplements have been shown to help with pruritus, and omega 6 supplements can help with skin and coat quality.


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