How can I tell the difference between mange and allergies in my 11 month old puppy?

She lives outside and she eats grain free food due to previous allergic reaction to science diet. She's been doing great and the all of the sudden she's been losing tons of hair on her tail and around her bottom. I can't afford at the moment to take her to the vet if it is just allergies if that's the case I know how to deal with it. I just need to know how to tell the difference between the two. She's very active and she is supposed to get spayed at the beginning of june and live inside for a week (she hates to be inside). So please help I need to know what step to take next

Easy, take her to the vet

It's most likely a grass allergy since it's around her bottom and tail, or possibly a flea bite dermatitis. Of course the only way you'll know sure is for a vet to examine her.Mange would be widespread throughout her entire coat, not localized.But having severe allergies can cause a dogs immune system to weaken and make them susceptible to mange. Best thing to do is have her on a monthly flea/tick topical that also protects against mange..

Puppies have a high propensity to be afflicted with demodectic mange due to their still immature immune system. Demodectic mange is caused by demodex mites which are actually present in most dogs. Puppies get the mange mites when in close contact with the mother while nursing.In most cases, the mange condition will disappear when the pup's immune system develops and can keep the mites in check. If you wish to banish this condition sooner, you must be extremely careful as to how you treat it.As you ay already know and for the benefit of those who read this post and are not familiar with this problem, mange is a skin condition caused by tiny mites that you can't see with the naked eye. There are three types of mites that attack dogs most often: demodectic (not contagious and may itch or not), sarcoptic (very contagious and extremely itchy) and cheyletiella (contagious and mildly itchy). Vets can do a deep skin scraping to detect the presence and type of mite.The typical symptoms of mange as the condition progresses include hair loss and scaly or crusty skin. If the mange condition causes itchiness, scratching opens the door to secondary skin infections (bacterial or fungal) that may cause an unpleasant odor. Regardless of the type of mange, in order to cure it you need to treat with a medication that kills the mites. The flea medications will not kill the mites.The mange medications most often prescribed by vets contain pesticides and other toxic chemicals that are detrimental to your dog's health with resulting health issues that you will have to face sooner or later. These medications include Ivermectin (also known as Ivomec) and Amitraz (also known as Mitaban). See the links that follow for toxicology information. It is always advisable to check the veterinary drug database for side effects of any medication prescribed by your vet http://www.drugs.com/vet/ Thankfully, there are a number of effective alternative treatments out there that are safe and natural at a reasonable cost that will kill the mites. You can easily do some research in the Internet to find out about these and compare your options.I prefer the 'spray type' because it is inexpensive, very effective, convenient to use (no mixing and no mess), and it is natural and harmless to pets and humans.Hope this helps.Toxicity:http://www.petmd.com/dog/conditions/toxicity/c_dg_ivermectin_toxicity\http://www.drugs.com/sfx/ivermectin-side-effects.htmlhttp://www.drugs.com/vet/mitaban.htmlhttp://www.ncbi.nlm.nih.gov/pmc/articles/PMC1481314/?page=1http://www.petmanage.com/dog-health/what-is-amitraz-toxicity.htmlMange spray:http://www.florapetnaturals.com/online-store.html