Thank you, Michael.
Now as I am sure you can appreciate, the mystery of what makes a cat incessantly over groom, or pull out hair can be a real challenge to get to the bottom of. This is because feline over grooming can be caused by a number of triggers. The reason I have asked about fleas and whether you see her grooming is because the first step to identifying the trigger for her signs is to try to determine if she is grooming because something is irritating her (ie allergies to flea saliva/food/pollens/environmental agents, bacterial skin disease, etc) and thus driving her to do so, or if she is grooming as part of a anxiety/stress response.
Now if she has no changes to the skin, we can put concerns like bacterial or fungal issues lower on our list of concerns for your lass. And I must note that with her constantly grooming in front of you, that usually fits more with grooming due to skin irritation as opposed to stress based overgrooming (which usually presents as a bald kitty that the owner doesn't see grooming excessively). So we'd be less concerned about her friend upsetting her and more concerned about what he is bringing in the house.
With that in mind, since you haven't mentioned any diet changes in the past two months, we can hopefully assume that dietary protein allergies are not an issue here. This leaves us with flea saliva allergies (which is very, very common) and environmental allergies (less so this time of year - though dust mites, carpet powders or laundry powders could be culprit). And just to note, if she is targeting her back instead of her belly or groin region, this will further tell us that we are likely looking at a flea allergy dermatitis (since the target area isn't an "easy to reach" spot but instead the focus of where she is being irritated). So, that would be our number one suspect here for your lass.
Now as we consider flea allergies and treatments for those creepy crawlies, I must warn you that BM is not a very good product for fleas. The reason those products are on the grocery store shelves is because they are old and the level of parasite resistance is very high (since those fleas that would have been sensitive died when the powder components were new 20+ years ago. And the ones that remain and harrass our cats today are the descendants of those who resisted those drugs back in the day). So, we find it may work on occasion (and its great when it can) but more often we find this product lets us down more often then now.
That aside, the reason why we always have to be aware of fleas is because this is one of the most common types of allergies of the cat. The problem with wee kitties with sensitivities to fleas that they aren't allergic to the fleas themselves. They are allergic to its saliva. So, all it takes is one flea having a nibble to start things off. The body releases histamines and the allergic response takes over. This irritates the skin and in mild flare ups (often what we see if a suicidal flea bites a treated cat) then we can just see overgrooming and some will even start pulling out tufts of hair. And the back can be common sites to see this. And since the problem is an allergic response, the cats keep grooming and get caught in a vicious cycle or irritation. The fact that this over grooming is going on long enough to cause hair loss is quite suspicious of a chronic allergy that is just not settling because she keeps grooming it. And if it is flea saliva induced, the flea that may have bitten her is probably long since dead (so we may see no sign of it when examining the coat). Cats caught in this kind of allergic response often respond well to religious flea treatment but sometimes need additional short term medications to soothe the inflamed immune response and help break the cycle.
Therefore, to try to break any allergic cycle (and rule out the allergies for causing her signs in general), you can try treating her with an anti-histamine. Anti-histamines can settle allergic skin reactions in early stages or mild cases since the skin irritation is an allergic response. Typically in these cases, we will use Piriton for these wee ones (ie 1-2mg or 1/4 – 1/2 tablet of a 4mg Piriton tablet up to twice daily). Do note that while anti-histamines will break that the irritation cycle, it can make kitties drowsy. Therefore, we always keep the dose low and if she were to be drowsy on this, then we'd reduce the dose to once daily for her. And of course, this medication shouldn't be used if your kitty has any pre-existing conditions or is on any other medication without speaking to your vet. Furthermore if it has been three weeks since the BM, I would suggest retreating her with a good quality flea spot on treatment (ie Advantage II, Advocate, etc).
Furthermore, if her skin is very irritated, you may wish to consider bathing her (though most cats won't appreciate this and it isn't required to do so). If you were keen, then its best to use skin soothing emollient shampoo ((ie Episoothe, or oatmeal based ones) to soothe the skin. If she continues to pull hair, then you may also have to consider using a buster collar or baby t-shirt (with an elasticated waist)/ reversed boxer shorts (so her tail can go out the hole) to protect her skin.
Overall, it sounds like despite the powder treatment, your lass is having a reaction to flea saliva. Therefore, it is worth considering an alternative flea product for the future but also using a short course of anti-histamines to break the itchiness cycle. And if you don’t find her skin settling with this addition then it would be worth seeing your vet to discuss treatment with a strong long lasting injectable anti-inflammatories to halt the itching if necessary.
I hope this information is helpful.
If you need any additional information, do not hesitate to ask!
All the best,
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