You are certainly a terrific pet sitter to be so concerned about this dog, and by your description, yes it sounds like there is a skin infection (bacterial or yeast or both) probably secondary to an underlying allergic cause (fleas, food allergy or pollen/dust allergies). Veterinary exam is obviously required to identify the type(s) of infection present so that the appropriate oral antibiotic and/or antiyeast medication can be prescribed for 3-6 weeks, ideally in conjunction with antibacterial/antiyeast shampoos such as Malaseb or KetoChlor and appropriate ear antibiotics and cleaners. These shampoos can also be purchased online. A hydrocortisone spray can be tried, but if infection is present, it is unlikely to help; the same is true for oral antihistamines, but you can try them (ie. benadryl 50mg twice daily for a 50 pound dog). A T shirt may be helpful to reduce self trauma due to scratching until the owners get back into town. A hypoallergenic diet trial is certainly in order, although it will need to be ascertained if the dog has been exposed to lamb already, since it is a very common protein in OTC dog foods. A better alternative may be Natural Balance duck/potato, if that is available in Canada, and of course the owners must commit to feeding absolutely nothing else for 6-8 weeks, and treating the secondary skin and ear infections during this time--the diet change will not resolve the infections, but may prevent infection recurrence if the underlying problem is food allergy. If the dog's itch/infections recur despite treatment of infections and the strict hypoallergenic diet, then underlying atopy (pollen/dust allergies) would be the cause, and options would be to continue to treat the symptoms with medications (antibiotics, antihistamines, steroids, etc) for the rest of the dog's life, or to perform allergy testing and desensitization injections to identify and treat the cause of the problem.
Kimberly Coyner, DVM DACVD
Natural Balance is a possibility but it is quite a bit more money (although it is one of my first choices for allergy formulas), $60-70 a bag vs $55 for the acana. There is no lamb in the beneful and as far as I know that is the only food he has ever been on.
I did try a 10mg of reactine (found a couple pubmed studies that used that one since that is the one I had on hand for me) and has done nothing so far.
My hunch is that it is a dust mite allergy because their house is quite dirty (pretty gross actually), and this is the first time in months that my allergies have acted up (dust mite and cats) but they go down when I go home for a couple hours to play with my two cats. Although I am due in a week for my allergy shot sooooo might just be that.
Thanks for the tips, I'll see what I can do.