Could Recurring Itchy Acne On Forehead Be Due To Hormonal Changes?

Hi Dr. I suffer from allergies, I am a smoker 31 years old with no health issues. Within the last 2 years I have developed adult acne, its generally on my forehead and it goes and comes. What is causing this Soda, Stress, Allergies, Cigarettes??? I was known for having PERFECT skin ALL my life and I have never had any type of breakout or acne until I turned 30. Is it my hormones I do live a busy life with 4children and a business, The patch gets bumpy but not red sometimes it itches, and then it dries, fades a way then come back, Thank you for your help or any advice.