catching, sneezing???

Hello everyone! I have a 6 month kitten who recently started to scratch around the neck and sneeze. It doesn't happen very often but I was wondering if she could be allergic to something. Her habits seem to be the same, no change at all. I understand the first reason for the scratching and sneezing is fleas, however I've been putting flea treatment every month since the age of 8 weeks, when I got her. Is it possible that she got fleas despite the medication? About the food, I've been giving purina pro plan since the age of 8 weeks old and she has never scratched herself like this. She doesn't do itvery often but what is your opinion? Thank you in advance!!!

Scratching around the neck and head CAN be a sign of food allergies, but for her to only do it every so often is a little unusual,unless you are feeding different varieties of the Purina Pro Plan and the scratching coincides with a certain variety.  Could that be the case?  You might need to start a log to find out, assuming you are feeding canned vs dry.  Oh, and BTW, cats can eat the same food for years, then suddenly develop an allergy to it. 

Otherwise, it only takes ONE flea bite to cause issues, and I suppose it's possible that a flea could have gotten to her, or perhaps a mosquito?  Or maybe even some other biting insect, even an ant? 

Have you been to a Vet yet?  They might be able to give her something to help with her itchiness.  Have you checked all around her neck to see if you can find any sort of bump or rash of any kind?