We have one and it really does help to take the itch away. I got a bite on my back a few weeks ago and it was itching like crazy. I gave the bite 2 or 3 consecutive 20 second zaps with the device (with about 20 seconds rest in between each zap) and the itch went away all day long (for about 16 hours straight). It did return later that night, but I zapped it again and got another 16 hour or so gap of perfect peace. In total, I only had to zap once in the morning and once at night for 2 days in a row, and that was it. I love our little zapper.
You could also try making a small paste in the palm of your hand,of baking soda and water. Then dab it on let it dry.
I've heard eating a banana helps repel those little pests,something about potassium in the blood stream.