Suddenly allergic to DGPs dog?

[rocketupbum]

My DS (3) seems to be suddenly allergic to my parents dog. In last 2 weeks he now seems to be wheezy, coughing and runny nose within an hour of arriving at their house.
This seems to settle once we have left and over about next few hours.
I am gutted, mum and dad really help out with childcare and DS loves to go there. Also the dog is much loved and fab with the kids.
He has had no other previous allergy reactions- can it come on this suddenly?
Not sure where to go from here. Any advice or experience here would be very welcome.

Yes allergies can start at any time.
Have you tried giving him antihistamine before he goes there.

Also make sure if he touches the dog that he doesn't touch his face without washing his hands.

DH is allergic to animals and finds that the longer he is around an animal the easier he finds it, as long as he his careful about washing hands etc.

DH has heaps of allergies and I kind of hoped we have managed to escape with DS!
What antihistamine would you use?

DS has hayfever so was given loratadine by the doctors which is a one a day, not sure what age it is suitable for but he was been taking it from about 6.

If the visit is just short piriton works faster and is better if a reaction has already started.

My cat allergy didn't kick in until I was 16... Apparently you can be sensitive, and with time and exposure to the allergen become eventually allergic.

Oh poo. Anyway thanks for the advice girls. We have an appointment with GP next week so will pick his brains.

Had lots of cats as a child and only became allergic as an adult with no cats.