Our male Shih Tzu has in the last few months become increasingly aggressive. He is not food aggressive and I can take toys, bones, food from him with no problem, but if he has a leaf on his chin or a toothpick and I go near his mouth he snarls and bites. He loves to play and we can pet and play with him with no problem but when he is sitting on our lap or laying beside us and we start to pet him he growls and snaps. He never liked being brushed or have his face wiped but now he gets so vicious that we cannot even attempt it. He has bitten me (his Momma and food/care provider) several times and drawn blood. It hurts of course but my heart is broken. We have stopped letting him sleep with us, are working on the pack leader stuff (we've watch the Dog Whisperer but so far it hasn't helped. He has allergies and I thought perhaps the itching stressed him - he was given a dose of steroids and it seems that immediately the aggression started. We are feeding him grain free food and venison or lamb and I am at my wits end. We dearly love him and he can be so sweet most of the time, but we are worried because we have 7 grandkids and he has growled and snapped at all of them, biting a couple of the older ones. Help!!
Sorry to hear about your problems! It may be something with the steroid causing mood changes in your boy, though I've never heard of steroids interacting like that...have you talked to your vet about it? Also, is he neutered? You may want to look into having it done if not...
As far as the growling and snapping when he's on your lap - my advice would be to stop letting him up on furniture or on your laps for a while - a few weeks at least. Then, only allow him up when you invite him - don't let him just jump up and stay up - he can only be up on furniture or people when you ask him up. If he gets up on his own, immediately push him off. Try training him to "get up" and "down" for getting on and off furniture.
This sort of training helps your dog realize the couch and your laps are not his "property" and that its a special thing to be on them - it should help with the snapping.
For the grooming issues, if you're determined to do it yourself just break it down into steps and take it a little at a time, with a lot of repetition. Try just rubbing his whole body every day, just to get him used to you touching his face, body, tummy, paws, everything.
You may find a muzzle helps make you feel a bit more at ease - though I understand if its not something you'd want to try.
I hope that makes sense - please let us know how things are going! And good luck!
I would like to suggest the following 3 things since it sounds like your pup only gets aggressive when he is being touched around his mouth and it seems to have started after taking the steroid medication:
1) Consult with your vet including the behavioral changes. I am copying below some info I found regarding side effects of Prednisone:
Behavioral Changes: Unexpected change in the dog's behavior could occur due to long-term use of this drug. Excessive restlessness, anxiety or aggression could be attributed to the prolonged use of prednisone. Hence, it is important to monitor any abnormal behavior in the dog.
One of my dogs has allergy and although I've got Prednisone prescription in hand I am trying to do without it. I have been giving Benadryl (1mg per 1lb) twice a day. She still ithches but at least Benadryl doesn't have much side effects according to my vet, and it can be used as needed basis, while Prednisone cannot be stopped cold turkey.
2) Start hand-feeding your pup about first half of his food. The idea is for him to get used to have your hand around and under his chin or mouth. As he gets used to it, try to touch his chin as you give some him some kibbles. One thing you want to avoid here is to pull your hand out as he growls... If you do, it is same as teaching him that growling works. Same for biting - if he bites and the thing he didn't want (being touched by your hand) disappear, he will keep biting you.
3) Work on basic obedience so that he responds to what you say, such as "No" (I personally hardly use "No". "Uh uh (sp?)" is good enough for my dogs to know that their behavior is not what I want) or "Leave it". If he starts growling tell him "No (or Uh uh)" and if he stops growling, say "Good boy!" and give him a lot of praise. However, growling is a warning from dogs before they actually bite you so go slowly with patience so that you don't push him to his end of the rope.