Scratching like crazy need some help please

That's not just allergy ... that IS (I'd bet next week's pay on this) "flea allergy dermatitis".  It always starts at the base of the tail and goes up the back and down the back of the legs.  Classic pattern.

A dog with flea allergy dermatitis is literally allergic to the flea spit.  When the flea 'bites' it's spit is like venom to these dogs.  ONE bite from ONE flea will make one of these dogs miserable for months.

First off, the gal needs to get a handle on the whole flea problem -- Frontline (probably Frontline plus or maybe even better would be Frontline spray) probably more than once a month.  Not something where the flea has to bite the dog to 'work'. 

But she needs to do two things almost simultaneously -- and that will take her moving out for the weekend probably.  She needs to bomb the house (a good egg-inhibiting flea bomb) in EACH room (or two if the room is big).  Open her cupboards and closets.  Put all her food, dishes, pans, silverware in heavy plastic bags first.  But flea eggs will hide in fabric, rug, closets, etc.

Then she needs to treat the yard -- fleas live in dirt/grass and particularly like the area right around the bottom of the house -- they literally can and will crawl thru concrete!  So outside she needs to treat her yard heavily (same time she bombs the house -- that's why I said she needs to move out for the weekend -- this is a LOT of work).

You stay gone 3-6 hours for the bombs to work inside.  Then you have to air out the house for 3-4 hours and then scrub the floors, counters, etc.  Did I say "a LOT of work"??? yep.

Then, honestly she needs to repeat this whole thing in 7 days.  To break the back of the flea life cycle.  If you don't do it right you won't break the cycle. 

Things like fresh garlic in the dog's food can help make the dog less attractive to fleas.  There are other natural products around that can help.  Once she gets this all treated she can go on.

If she's in an apartment it's tough -- she has to do this stuff -- but yeah, you actually have to spray around your own building because the flea spray maintenance they do usually isn't nearly sufficient.

Diatamaceous earth is a BIG help -- there is lots on that in the search feature here.  It's a more natural product that will help control the fleas after she gets the cycle broken.

Does this dog get walked?  Or is it allowed to be loose over a large area??  It's likely picking up the fleas in a variety of places and narrowing that freedom can help contain the problem. 

This isn't as expensive as it is A TON of work.  But it can be done.  It's a bad bad flea year -- so she'll probably have to use Frontline or Advantage more frequently that normal particularly to get this under control. 

The dog's skin will heal as you elminate the fleas.  Like I said, all it takes is one ... but you can do a lot of things to help it.  I hope she's willing to make these changes. Having a friend to help DO this stuff will make a huge difference.

I'm not a huge advocate of a lot of chemicals but sometimes you have to do what you must to get the situation under control and THEN you do stuff to maintain the peace. 

Thank you for your reply.  That is alot of work.  And the kicker is that she lives in her grandmas 5 bedroom 2 story house. haha  I do not know if all that is possible but I will tell her this.  And yes the dog roams freely in a huge yard so perhaps she can get a run or something.  Again thank you. 

So are all those rooms used on a daily basis??  Simply close the doors on ANY rooms she can and seal around the edges of the doors with masking tape.  YES that will work and any fleas in those rooms will die if she leaves them at least a month TOTALLY closed.  I've had to do this in a large house before -- I'm totally aware of HOW much work it is ... which is why I belabored the point.  *sigh*  It works tho ...
 
Any bedding that she can just seal it in a heavy duty trash bag and LEAVE it for at least a month undisturbed -- see if fleas don't feed on blood they will die eventually.  Eggs already laid will hatch and DIE.
 
But for the parts of the house that can't be sealed off, she needs to bomb.  But that means no "broken rules" -- she's gotta absolutely leave those sealed parts of the house totally undisturbed for at least a month to wait thru the life cycles.  2 months is better.
 
She's be far far better off to go to a "do it yourself" pest place -- grocery store bombs won't work -- better to get the good stuff.  And when she re-bombs in the next week -- use DIFFERENT chemicals.  So you kill any that may have become resistant.  (If they live thru one bombing they will 'resist' the chemical the next time.)

Sorry about the flea problems.  I would assume that Frontline and Advantage are killing the fleas but not helping with the allergies, which would be entirely different ball game. The dog needs medication for the allergies. 
 
Since the infestation is so bad and you have a huge area to contend with I would call in a professional est control erson to get rid of them, inside and out.   I have found that the bug bombs worthless, because they cannot reach the entire areas.
 
If it becomes to much how about finding a rescue org to take the dog instead of the shelter?

Looks like you got lots of good advice... the Vet should have used "Capstar" it gets rid of fleas in 30 seconds.... if the dog was bathed and then frontline was applied that is a bad thing. You need to put frontline on a couple days before appling or put it on a couple days after. If you use "Capstar" you must wait 48 hours before appling a topical flea treatment. " Capstar' is a pill that they take. I used it many a times on rescues that came in infested with Fleas and needed immediate help.

Unfortunatly Callicritturs is a 100% correct on this one. I know it sound slike a pain but think of what the poor dog is suffering. Not to mention know she dosnt want it around the baby and that stinks! Please tell her not to take the poor thing back to the shelter just because of this. She'll have to bomb the house anyways!

Flea traps are good to use also. To help with the flea problem on the dog and to help heal the skin problem tell your friend that they can get this and use it on their dog.
Neem Oil Shampoo
[linkhttp://www.pet-dog-cat-supply-store.com/shop/index.php?page=shop-flypage-2139]http://www.pet-dog-cat-supply-store.com/shop/index.php?page=shop-flypage-2139[/link]

Try Advantix, not Advantage.  Advantix repels the fleas and kills them if they bite.  It also repel mosiquitos and kills ticks.  There is also an awesome spray called Ovitrol.  Her vet probably uses it in his/her office.  You can use it on the dog and furniture, clothes, even in the vacume cleaner (although putting a cheap flea collar in the vacume will also kill fleas on the carpet).  You can order Ovitrol on line and some Tractor Feed Company's carry Ovitrol