They ate my neck up....front, back, side to side! I have HUGE whelps on my neck from them. The one place I failed to spray! AHHH!!
They like to get in your eyes...not sure why...and I really don't want to know why they want in my eyes. They will bite you in your eyes and it will swell REALLY big.
There isn't as much info on gnats as there is mosquitoes and ticks. I can tell you that they swarm...in MASSES. They will not leave you alone no matter how much you swat at them. DEET will keep them from biting or lighting on you (unless you do not spray your neck). If it rains...they will still swarm. I don't know what they get from biting humans, unlike ticks and mosquitoes. I think it is for pure annoyance.
Protect your selves from theses pests. They cause 100's of diseases. All of us spend a lot of time outside with these pests. If you garden, you are subject to ticks, mosquitoes and gnats. So please use insect repellent, light some citronella candles, and get rid of those buckets holding stagnant water.
Sorry for the long post....I am done now ;)