What is with my itchy skin?

I am four months pregnant and everything seems to be going perfectly well except for the rash that I have developed on my face. I have scrubbed thinking that maybe its dead skin as a result of bad weather but nothing much has changed. I use Vaseline religiously but now my skin has started to itch too. What can I do? What could be causing this? What do you recommend? 
Dr Rachna Pande
Dr Rachna Pande
Times Reporter