rescue becoming more aggressive?

Question
Hello,
About two months ago I found my dog in the park, she had a severe case of demodex mange. She is currently being dipped, has been checked for worms, and is vaccinated. After I was sure that she had demodex I introduced her to my dog. The two of them get along great and are crated when I'm not home, but recently I've been taking her out to socialize her (PetsMart, dog park, etc) and it seems the healthier she is getting the more aggressive she is becoming. She is already leash trained for the most part, but if another dog walks by she lunges and growls, or if she is off the leash she will chase another dog down and attack. I'm sure there are similar articles, but I did not see any. I've never dealt with an aggressive dog before and I'm completely at a loss, if you have any advice it would be much appreciated.

Thank you,
Tanya

Answer
Without observing the behavior the situation is difficult to assess. I suggest getting a dog trainer out to your home to give you a consultation. http://www.betterdog.com

Your first job is to figure out just what it is that's going on here. Is she afraid, is she protecting your other dog, is there a difference on or off the leash, is there a difference at home or away, does the number of dogs in the area make a difference? For example is she more or less aggressive toward the dog being walked by on the street verses a dozen dogs running around at the dog park? Has there been food or toys around during any of these aggressive encounters? Is there any pattern to the dogs she's gone after? Are they bigger, smaller, male, female, neutered, not? Is she better in an enclosed area or an open area? When she attacks, what is her body posture like, what are her ears and tail doing, what is the position of her head and is her fur on the back of her neck standing up? How soon before the attack does her body posture change? Describe the changes.

Do some experimenting and observing and follow up with the answers to these questions and I'll be able to help you out in detail. But I warn you, the process of desensitizing a dog to anything is a long one and you can never trust a dog who has once been aggressive 100% to never be aggressive again. But it's not hopeless.