After a recent visit with an Allergy and Dermatology Vet specialist in Austin, TX, I thought I'd share some information I received. Beginning in March, Havanna had a lot of issues with scratching and gnawing. She lost a great deal of hair and was miserable, and after four visits to the local vet, he decided she needed to be referred to a specialist. This is the information that I learned from the specialist and applies in general to most dogs:
The three most common allergies in dogs are food, inhalant (atopy) and flea. Food allergies can only be ruled out by a strict 8-10 week food trial with a prescription hypoallergenic food. The blood tests that are being offered to determine food allergies are not considered accurate or acceptable by specialists because they have a high percentage of false positives. Dogs that are or become allergic to food are prone to ear infections. They also tend to "scoot on their behinds" a lot.
Intradermal skin testing is the preferred test to diagnosis inhalant and flea allergies. This is the same test they do on humans. Dogs that are allergic to fleas tend to scratch and gnaw on their back, around their tails. Inhalant allergies, as with humans, tend to be seasonal with whatever grass, tree, pollen, etc they are hypersensitive to.
Havanna was not exhibiting any of the signs of a food allergy, but was exhibiting signs of inhalant and flea allergies. We decided to do the skin testing on her (NOT cheap!). Amongst a few other things, she was found to be highly allergic to fleas. Although she had no signs of fleas on her, the specialist advised us that one flea on a sensitive dog could cause a lot of problems. This began a bit of a conversation about fleas and ticks.
We had been giving the girls Revolution, but after hearing from at least four different vets that this was ineffective and not recommended (they all were having dogs become heartworm positive, even though the owners were faithfully applying the Revolution), we tried K9 Advantix. Havanna lost hair in the areas we applied the solution, so our local vet had told us to not use it anymore and had recommended Trifexis (this is the same thing as Comfortis, but with extra protection). The specialist highly recommended Trifexis (she gives this to her dogs) and advised us to not use spot-on treatments like Revolution, K9 Advantix, etc. Independent studies have determined that the spot-on solutions lose their efficacy after less than three weeks (the active agents could only be found in dogs' hair follicles after three weeks, which was not giving them any protection). She stated that if you are giving spot-on treatment, you should apply it every 2-3 weeks for it to be most effective.
My concern with the Trifexis was that it did not cover ticks (labeled for fleas and heartworm). The specialist told me that she had contacted the manufacturers of Trifexis personally, as she was hoping they could make the pill more pallitable (says that it's beef flavored, but dogs don't seem to like it). They informed her that during their trial studies, they had determined that the Trifexis did help with tick control. However, since their trial was only approved for flea and heartworm, they could not label it as helping to control ticks (trials take atleast two years to complete, and the manufacturers didn't want to go back to include the ticks). The specialist stated that if your dog doesn't have lots of exposure to ticks, the Trifexis should protect him/her. If, however, you live or plan to travel in a high tick area, she recommended a Preventic collar.
For inhalant allergies, she recommended 1/4 tablet of Zyrtec. This has proven very helpful with Olivia, who sounds horribly congestion without it.
To the best of my memory (if I don't write it down, I forget....), this was the most important information she gave me. Hope someone finds something here useful.....