Thank you for your patience. There are a few things that could be going on here with your two. The tremors are relatively common in miniature breeds like this, and some will often shake whatever the ambient temperature. This is usually behavioral in nature rather than a sign of their body temperature, and it generally isn't an indication that they have a more severe issue lurking in the background. Given they both have this skin issue however, we do need to keep it in mind that the tremors could be related to this.
Firstly - you need to make sure that both of your dogs are definitely up to date with their flea control. Make sure you are using a flea product appropriate for each of their weights. Even though you may not be able to see any fleas on either of them doesn't mean there are one or two lurking within their fur and oftentimes this is all it takes for a dog with flea allergy dermatitis. In each of your dogs' cases it does sounds like they may have an underlying allergy of some sort with secondary infection, however this could also be caused by parasites or fungi (ringworm or yeast).
Bascially dogs are allergic to four main things - food, fleas, grasses/plants (contact allergy) or environmental allergens (canine atopy - the dog version of ezcema). It is quite possible that you have already worked through all of these with your Veterinarian, but I always like to ensure I have talked through each of these with my clients. Flea allergies are avoided by strict flea control - every 3 - 4 weeks with Advantage or Advocate or every 5 - 6 weeks with Frontline (or similar products). You must also ensure all pets in the household are treated at the same time. For a food allergy, you need to undertake a food trial with a 'hydrolysed protein' diet such as Royal Canin Anallergenic or Purina HA and needs to be fed SOLELY for at least 6 - 8 weeks. After this time if you are seeing a change in each dog's skin issue, you can slowly introduce different foods week by week with the guidance of your Veterinarian. Contact allergies are best treated by avoidance of the plants that are to blame, but identifying the exact cause of a contact allergy can be very hard. A referral to a canine skin specialist may be the way to go in this case for either a skin patch test or a blood allergen test for each dog .
It is also possible that your two little ones may have skin mites as they commonly cause a reaction like this and could explain why both dogs are affected. These could be either Demodex (less itchy) or Sarcoptes mites (VERY itchy) and you should ensure a full Veterinary check up so that he or she can carry out a physical examination and possibly a skin scrape to check for mites and lice, as well as signs of fleas. The next step would be to double check for fungal disease (such as ringworm) and there are several tests for this including a UV light and a fungal culture. It could also be that your dogs have a bad yeast problem - and a good medicated shampoo such as Malaseb may well do the trick! Again a full Vet check will be able to confirm or deny this. If after these tests there is no diagnosis, the next step would be to carry out a food trial as above. It sounds like you have tried a range of dog shampoos on them already, but definitely see if your vet can prescribe the medicated 'Malaseb' shampoo. This shampoo (or a similar product containing both Chlorhexidine and Miconazole) is the most ideally suited for this sort of situation. This requires you to make a lather and leave this lather on for 10 minutes before washing off! For many clients this is easier said that done, but it is SO important.
If you can try keeping the two dogs away from the heater for a while, that will help to rule out a heat/follicular rash as the cause of the issue. If they are always in front of the heater, then this could potentially be a cause here. Finally, please get your local vet to check and clear their anal glands the next time you have them at the vet clinic. Anal gland issues commonly cause an issue and irritation around the back and around the private area. This could also potentially be a cause for the tremors/shaking if they have full or impacted anal glands. As anal gland issues are very common in miniature dogs, getting this checked this week would definitely be a good idea. If they both have very full anal glands, then adding in some dietary fiber (such as psyllium husks and seeds) can help these to clear more regularly. I hope all of the above makes sense? If you have more questions or if I can help in any other way, please do not hesitate to ask! If you would like to accept my answer, please press RATE OUR CONVERSATION (I am not compensated in any other way). Bonuses are always welcome. Thanks! I hope to work with you again soon!
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