Other than menopause, what can cause hot flashes?

I seem to be having hot flashes the past couple of days. I feel like I'm radiating heat. At night when I go to sleep mostly. My feet feel really hot and my bed sheets & pillow get really hot. Yesterday i was pretty relaxed and while at work, the air was fine, but I started feeling really hot and started sweating. Are there any physical things that can cause this, other than menopause? This is different from just being hot...I feel like I'm "in heat".