Possible Mange

The vet visit will hopefully give you an answer about what's causing her itchy skin.  Sometimes a secondary staph infection can happen when dogs have allergies or other conditions that cause them to scratch which will cause areas like you describe.  A round of antibiotics and sometimes prednisone is often prescribed to clear up any infection and to combat the itchiness.  Let us know what you find out.

Welcome to the forum, btw!  It was a terrible cedar pollen season this year.   I live a little south of the hill country and the clouds of pollen blowing down here broke all the records.  :(

Your title says "Possible Mange" -- and there are many different types of mange (and all are different mites entirely) so first I have to ask you some questions:

1.  "very itchy" -- that can be a loaded statement -- does she scratch CONSTANTLY?  Like she wakes up to scratch?  You can't disconnect her from scratching to get her TO stop?

2.  What sort of heartworm prevention do you use?  Interceptor/Sentinel actually are wonderful for sarcoptic mange and cheylitellia mange (and I know I spelled that wrong).  Milbemycin is really good for any type of mange or parasites where the mite/parasite bites the dog to feed on its blood.  It's dosed way higher than they dose ivermectin in HeartGuard or Iverhart (neither of those would be helpful).  Revolution is supposed to be good for blood-feeding parasites but honestly, typically is not.

3.  This is the biggie question -- are you or any resident human (or even other species) scratching?  You might see a small, fine red rash -- you almost might think "Gosh -- the darned dog's convinced ME to itch now!".  It can be anywhere but likely places would be any part of you that might touch the dog inadvertently -- like your waist if you sit next to the dog on a sofa, ankle, wrist or hands (or any part of your arm) --you can be bitten thru clothes but it's not as typical.  You don't typically see the bumps on a human because altho sarcops are zoonotic (meaning they'll attack any species) they prefer to breed in their chosen host.

That means if you see a bum on the corner who has scabies (that's what they call human sarcops) -- his mites can bite his dog, but it's likely they'll feast on the dog's blood (biting is what causes the itch) but they will go back onto the human to lay eggs.

So a dog with sarcops (who got them from another dog -- which can be anywhere from near a dumpster to a pee spot at a dog park) -- that dog's humans can be bitten by the dog's sarcops, but when possible those sarcops will only lay eggs on the dog (and that's typically what causes the little bumps)

4.  To be honest, what you are describing does NOT sound like sarcops.  Typically with sarcops you almost don't notice the bumps -- but the dog will literally scratch itself totally bald -- and the skin underneath can actually get toughened and almost callous-like.

5.  That said -- this could almost sound like demodectic mange -- but let me say right now -- You do NOT want it to be demodex.  not in a 7 year old female dog.  If demodex pops out on an adult dog like that, you've got major problems somewhere -- because typically demodex is a puppy thing when the immune system hasn't matured, but when it comes out on an adult dog it typically means that somewhere the immune system has taken a MAJOR hit -- meaning stuff like Cushings, Lupus, etc.

I can send you an article on mange -- it's something my husband and I have helped with many many times. 

6.  Since you're connecting this with cedar and I'm *not* in Texas I have to ask -- is this cedar that is somehow on the ground?  Or cedar trees?  educate me about what it is in cedar that triggers the response?  Cheylletillia mites are a whole different mite and they live IN certain types of plants -- like Spanish Moss and such -- very common in the South.  But again -- Interceptor would help

7.  This could easily be pure atopic allergies -- particularlyl if it's tied specifically to cedar.  That wouldn't be mange tho -- but when allergies come out on a dog's skin it often takes the form of big oozing sores -- and the hair sticking to the scabs would be typical.

Now -- it's also more difficult to treat (because you can't just kill a mite).  The thing I've found that has worked best for allergies is TCVM - Traditional Chinese Veterinary Medicine.  Acupuncture and the Chinese herbals are FAR more effective than just an antihistamine.  They will help the sores, as well as combating the allergy.

http://www.tcvm.com is the Chi Institute -- there's a locator on the left.  But feel free to contact me  and I may be able to help you locate someone.  Don't just make an appt with the first name you see -- CALL THEM and make sure they actually work with allergies and use the TCVM method of diagnosing AND the Chinese herbals.

ALSO -- just to add a comment -- IF you are dealing with sarcops (and it is possible) you can use just plain ivermectin on a Mastiff.  (you can't on all breeds).  But you can get Ivomec (which is farm strength ivermectin) and I can send you the dose chart for it.

Hope this helped.  Feel free to holler if I can help you more.