dislikes certain people

Question
I received your answer to my questions regarding my Westie not liking my daughter's girlfriend.  Well, to being with this girl is 18 years old and not a little child.  Anyway, she came to my home again last night and again my Westie went crazy, barking and regressing evertime she tried to get near him.  I even gave her one of his "cookies" thinking that the dog would realize that she only wanted to be his friend, but no way.  He would look at the cookie and still bark at her.  The whole time my dog was barking at her, he would get very tense and his whole body would quiver.  This time we had to put him in the backyard because when he gets very nervious, he also has  bowl movements.  I just don't understand why he does this only with this one girl - no one else.  I really would like to get an answer to this problem as I feel this is not your norm.  I would like to know why this problem with this one girl. Thank you for any being there when needed.  Sonia-------------------------
Followup To
Question -
My (3) year old Westie, KC, does not like one of my daughter's friends.  Since the first day she came into my home, the dog barks at her and if she tries to pet KC he growls at her.  What I would like to know is why does he do this only to her and not other friends or neighbors.  She has never done anything wrong to him and only wants to play with him as all the other people do.  Why does he do this?  I would appreciate an answer to this questions as it is very confusing.
Thank you for your help.  Sonia Flores
Answer -
Hi Sonia,

there is something about this person the dog does not like period.  What he needs is to go to training to be retaught that all kids are OK.

For now, KC is not to go near this child in case of a bite that can occur.

Speak with your vet for additional help.

good luck

Answer
Sonia,

Your dog either
1. had a bad experience with this person
2. this person LOOKS like someone it does not like
3. gets bad vibes from her

The dog really should go to a trainer and bring it to your vet for an exam.  For what reason the dog does not like this girl is beyond me.