Hello & welcome, I am Dr. B, a licensed veterinarian and I would like to help you today. I do apologize that your question was not answered before. Different experts come online at various times; I just came online, read about your wee one’s situation, and wanted to help.
Now allergies can be very frustrating for our dogs, their owners and their vets. In regards ***** ***** lass's history, the reason for her continued relapses is because the allergen that is triggering her signs (be it a pollen, diet protein or even dust or storage mites) is still present. So, when the medication that is soothing her over reactive immune system wears off, she resumes being irritated by this allergen.
Therefore, with this situation, she will likely need either further testing to pinpoint what the allergen is so that treatment can be targeted against it. Or she will need to be on continuous treatment to soothe that itch. By this I mean either an antihistamine or steroid (since antibiotics are only needed once her skin is secondarily infected). And I would note that if her signs are seasonal, then you may only need to keep her on treatment for part of the year.
So with that in mind, if she responded well to the antihistamine, then you can speak to your vet about repeat prescriptions to just keep her comfortable and prevent itching and secondary infections for her. Or if you wanted to try an over the counter antihistamine, I would note that we often will treat dogs with Benadryl (More Info/Dose Here). A low dose (ie. 0.5mg per pound of her body weight twice daily) can just be enough to break that allergy cycle, and give her skin the chance in needs to settle. We like to keep the dose low in dogs, as they can have drowsiness with this medication (just like people). And, of course, if she is only any other medication or has a pre-existing condition, then you do want to speak to your vet first before using these.
Otherwise, the next drug we need to consider is the steroids. These are the traditional treatment for allergies, as they are immune dampening drugs. That said, they are associated with a lot of side effects (ie increased thirst, appetite, weight, urination, development of Cushing's disease, etc). So, these certainly could help but if she has a recurrent problem, long term use could cause these effects and therefore may not be ideal for her.
Further to these options, I do want to note some longer term treatments that we do use in allergy dogs. One is called Atopica and it is an immune modulating drug that contains cyclosporine. This drug has properties that fight against inflammation and itching. It can take a few weeks to reach effective levels for dogs but it can really settle immune mediated allergic skin disease. You can read more about Atopica HERE.
Another option in regards ***** ***** treatment for allergic skin disease is Apoquel. This is a fairly new drug on the market that is designed for tackling the itchiness of these types of dogs. This new drug uses a different mechanism to stop itching and is not associated with those adverse effects. So, this would also be something to consider for her and you can find More Information here.
Finally, in regards ***** ***** initial mention of further testing, I would note that we often will immune test allergy dogs to determine what is causing their allergic reaction. This can be done via blood sample or intradermal skin testings (often by a vet dermatologist). It can be a bit more expensive but can be a good investment in the long term. Depending on the results, these can be used to develop an allergen "vaccine" specific to her needs. Depending on her specific allergies, these vaccines are often given over weeks to months until the dog develops immunity to those allergens that had previously made them itchy.
Overall, your lass sounds to respond to treatment but relapse when it stops and she is left with this lingering mystery allergen. Therefore, in that situation, we need to either consider allergy testing to identify what is irritating her so we can address it and/or consider long term treatment with antihistamines or one of the other options to keep her comfortable and itch free.
I hope this information is helpful.
If you need any additional information, do not hesitate to ask!
All the best,
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