@ZipLine-- I highly recommend aloe vera gel. Pure aloe vera gel will do, but if possible, purchase the kind with pain reliever sold at pharmacies.
Aloe vera itself is very soothing and calming for skin. So it can stop itching easily. But aloe vera gel with a topical pain reliever like lidocaine works even better. It relieves itching and pain in literally seconds. It's recommended for things like insect bites and even mild burns.
I always keep a bottle of this in the medicine cabinet. It's great for when the mosquitoes attack late at night and you can't get any sleep from the itching. Just apply the aloe vera gel on the bites and you will be asleep in no time. Of course, you need to do something about the mosquitoes too so that they don't bite again.