do to the heat/especially dry conditions alot of dogs are having trouble with fleas and scratching, the hair loss and scabs around the ears and throat tells me most likely from scratching.
other possibility is allergies.
X2 I have a dogo and a cur that were having the same problem I put Nu-Stock on the affected areas and took them baths with Dawn both of them are getting there hair back and no more scratching....This heat and the fleas especially in our area where the ground gets dusty is real bad.
I also used the Nu stock and Dawn.
But to make it alittle cheaper, you can buy straight sulfur and some mineral or baby oil and mix it yourself.
I bought a small tub of sulfur at tractor supply for about 6 bucks.