Your forehead--along with your nose and chin--is part of your T-zone, an area that's acne-prone for many people, especially those with oily or combination skin. Like all acne, forehead acne develops when the hair follicles in your forehead become clogged, causing inflammation and the formation of red or pus-tipped bumps on your skin. If you have breakouts on your forehead that don't respond to home treatment within six weeks, see a dermatologist--you may need medication to treat your acne.
Your menstrual cycle, pregnancy and menopause can all cause your forehead to break out if you're a woman. Shifts in hormone levels can cause acne for many people by stimulating oil production that can clog pores, according to the University of Maryland Medical Center.
Exfoliating can help clear debris from pores to reduce acne, but if you exfoliate too often or with harsh products, it can have the opposite result. Too much exfoliation can spread acne bacteria and cause your oil glands to increase production to compensate, according to Los Angeles dermatologist Howard Fein in Allure magazine.
Styling gel, smoothing serums, hair spray and other hair products can cause acne on your forehead if they have a chance to accumulate there, says Susan Binder, a New York City-based dermatologist in Glamour magazine's daily beauty blog. If you have bangs, your forehead may be even more acne-prone.
Hats and Helmets
If you regularly wear a hat or helmet, the friction it causes on your forehead could be contributing to acne there, according to the University of Maryland Medical Center.
Sleeping on One Side
If your breakouts are on just one side of your forehead, they may be caused by your sleeping habits, according to Binder. Consistently sleeping on one side of your face can cause breakouts on the side that's rubbing against your pillow at night.
Not washing your face before you go to sleep can cause breakouts on your forehead since makeup residue has a chance to slip inside your pores, says Bay Area dermatologist Katie Rodan in Allure. Rodan explains that your face heats up while you sleep, making it easier for anything on your face to penetrate your pores.