Please help - dog aggressive when on lead

[Raptorrrethy]

Our lovely three year old dog came from a shelter at 14 weeks old. He is a fabulous dog but in the last few months he has become aggressive to other dogs when he is on the lead. He lunges at them and growls horribly. We have tried distraction with treats, saying 'leave!' Etc but he's getting worse. Yesterday we walked through a market and he was awful, to the extent that people were moving away from him we have no idea why this has happened...he has not been attacked whilst on-lead, at least not with us. He did stay with a dog walker a few months ago who walked four dogs at once on-lead and all I can think is that something happened with her, but I really don't know.
Off lead he is absolutely fine and adores other dogs. In fact he will run off to,play with them and we have had to work hard on recall as he is not good about coming back as playing with the other dog is far more fun.

If anyone has any ideas I'd love to hear them as this is worrying us. We are getting to the stage where we are reluctant to take him out to,places where he will encounter other dogs whilst on the lead.

I should add that last weekend we were at a fair and there was a dog show. I was very anxious as to whether our dog could be entered or whether he would growl at the other dogs. However, he was fine. The other dogs were around him at the fair for a wile before the show, if that makes sense, so maybe he didn't consider them a threat in the same way?

When I say 'dog show' I mean a small, fun show with all the children and their dogs - waggiest tail etc!

My dog is dog aggressive on lead but fine off lead too. His aggression is basically frustration, he wants to play with and meet other dogs so much that he can't control himself.

Contact the dog walker to see if something happened when he was there.

The first thing you need to do is avoid seeing other dogs when you are out on lead. The more often your dog reacts like that the more often he will react like that. Also be aware that if you react to other dogs he will too!

Find out how close your dog needs to be to another dog before he reacts and try to stay outside of that distance, play this game.

It will get better if you work on it but it will take time. My collies behaviour to other dogs while on lead improves massively when he is allowed to play will other dogs a lot.

Oh yeah, I should have also said that a trip to the vets may be in order to rule out any health issues that could cause this reaction and find out about behaviourist in your area.

You might have come across this already but I posted something similar a while back. In our case he was nervous rather than frustrated though (depends what you think in your dogs case). There were lots of suggestions that worked brilliantly. He is still nervous occassionally but is so much better.

Thank you. I will check out the links.
He adores playing with other dogs and he loves it if people come here with their dog or dogs...he is not aggressive in any way at all. It's purely when he's on the lead...and the sounds that he makes are awful

It's definitely worse when he gets very close to other dogs, such as walking through the narrow market.

Dog on lead walks differently than free. In dog body language that is seen as agressive.