When has he been vaccinated? did i miss that part somewhere, if it correlates at all i know Thuja is often used as a remedy for vaccinosis, I also give Nico Sulphur 3x and sometimes Silicia 30x depending on the current issue. Im no expert so research or advice from a homeopath is a good thing!
Humidity:
If its that dry in your house you might try putting some water to simmer on the stove, or even in the crockpot to steam...also hanging laundry to dry can add moisture.
Im so dry and itchy right now i want to scream, my skin will crack and bleed if im not diligent with lotion or balm.
Topical yogurt:
don't put the yogurt in the ear!! only around and on it...I don't think i made that clear earlier.
Oh and the neighbors will think you are totally crazy if they see you rubbing yogurt on your dogs groin and personal bits....dont even bother explaining just smile and wave
Ask me how i know
Lateley i have been trying OTIC enzymatic solution with hydrocortisone in her ears and it seems to be helping, I am tempted to rub a bit of it into her armpits.
Fleas:
There could still be a flea or two hiding indoors though that havent been effected by the cold. Better safe than sorry as allergies can become proggressively worse with exposure.
The ONLY good thing about recently being without power for 10 days was that our house was below freezing for days on end, natural flea control. I use frontline on the cats and revolution on the dogs, but the occasional flea still gets in.
She is so allergic i just cant chance her getting bit as it sets off a horrid cycle that is getting worse with time.
Bathing:
I wouldnt want a wet stinky dog either, and dampness encourages yeast and bacteria to grow. Thankfully Nico has very short almost waterproof fur so she dries quickly!
You might try rinsing feet and legs only if he seems bothered down there.
But once spring and summer come id work on getting him acclimated to baths, its so nice to not have a total breakdown everytime they need a bath.
Apple cider vinegar diluted in a spray either with plain distilled water or sometimes I make strong Calendula tea to dilute it with can help calm itchies too.
Other random possibilites:
You say he is itchier in the basement, could it be an issue with concrete outgassing or some other chemical issue, i dont know how old your house is. Mold or mildew is also possible in a basement.
But both of my huskies have scratched immediately when they got some cuddle time on the bed with us. We figured out it was avoidance behavior rather than a true itch. Does he possibly not care for your basement.
what do you clean or mop with, could he be sensitive to it?
I use only white vinegar or a tiny bit of dr. bronners castile in the mop water after she vomited repeatedly after i used fabuloso to mop.
I also use vinegar in a Downy ball in the washing machine, it works as a fabric softener and also helps reduce soap residue on bedding and our clothing.
Dust mites can be a trigger as can Cats.