Great dane/pitbull mix scared of visitors

Question
I am a small woman, my dog is a 10 month old 70lb Black pitbull Great Dane mix. We live alone. I recently need to have some repair work done & discovered that he has an uncontrollable fear of strangers when they enter the house. He will calm down a little bit for women after about 10 minutes but not men.  He barks 7 growls cowers in the corner, runs around the house then back to his corner. He does not act like this in public & enjoys the dog park with all of its humans & other dogs. He has been well socialized at dog parks, street fairs,parades , visting friends houses, rafting, camping etc. Yet, every time a stranger enters our hose he acts scared & out of control.  I have tried the thunder jacket, it seems to keep him from shaking with fear. I have also tried giving him anxiety medicine.  
The last time I had company over I gave him anxiety pills morning & evening before visit, sprayed his kennel & coat with DAP & put his coat on him. I also played outside with him for about 45 mins before they arrived.The DAP spray worked ok but he was only somewhat calm & only found some comfort in his kennel.He would growl if he heard the mans voice. Do you have any suggestions to help him stay as calm at home when a stranger approaches as he does a the dog park?

Answer
Hello Barbara.  It sounds like you're doing all the right things with your dog.  The key to getting him comfortable with visitors to your home is to (1) keep him under his reactivity threshold while you're working with him and (2) always allow him the opportunity to escape to a pre-designated "safe zone" if he needs to.  Don't force interactions and don't allow anyone to approach him.  It's got to be up to him to decide if he wants to interact with anyone in your home.

Set up a training scenario with someone - preferably a woman - who he might already have met.  Give him his medication prior to the meeting and have his Thundershirt on.  Bring him into the room on leash after your visitor has already entered and been seated.  Instruct your guest to sit sideways from the dog and not make direct eye contact.  Have her be as still as possible. Stay at the furthest distance possible from your guest.  As soon as he notices her, give a high value food treat. This would be a tidbit of cheese, hot dog, beef, chicken - anything he really likes.  If he won't take the food, and you know he's hungry, then you're too close for his comfort.  Find a way to create more distance.

Each time he glances at the person, you can verbally mark the look with a "yes!" and then feed a treat.  He should soon catch on to the fact that when he looks at the "scary person" good food appears.  Any growling that happens during this process should be a cue for taking him back to his safe zone.  

If you are successful in getting him comfortable enough to glance at the visitor and take treats, you can very gradually take steps closer to the person.  If the dog has a favorite bed or rug to lie on, you can encourage him to relax at a comfortable distance and feed treats whenever he looks at the person and remains calm.  

At this point, have the visitor make brief eye contact with the dog and reward with food as long as he stays calm.  The next step would be for the person to stand up, then move around the room - but never approach the dog!

This technique I described is based on Lesilie McDevitt's "Look at That" game from her book "Control Unleashed".  You can google this to find videos of the skill being practiced with reactive dogs and find ways to use it in your home with visitors.

One you are successful with a female visitor, invite a non-threatening man over and start from scratch.  If you have unexpected visitors or people that can't remain still

Please let me know if you need clarification on anything I've mentioned or you have further questions or comments.   You've done great work with your dog so far and I'm hopeful that this technique will work for you.