19-Month-Old Wakes Up in the Middle of the Night Screaming?

For about the past month, my 19-month-old daughter has developed this habit of waking up in the middle of the night (usually around 3am) screaming. She usually goes to bed without much trouble, so this is really confusing the heck out of me. I am almost always the one who puts her to bed, and we have a nightly routine of a bath, pajamas, a story, and a little prayer. It has gotten to the point where whenever she wakes up screaming, I just take her and put her to bed with the wife and I, and she settles down (usually). I know this is not the correct method of handling this, but most of the research I've done hasn't seemed to help much. I don't know if it is night terrors, because when I enter her room she is standing up in her crib, wide awake, trying to reach for the light switch. But man, her screams are bone-chilling! What do I do? Some people suggest letting her cry it out, but there have been periods that I've waited for 45 minutes and there is no ceasing of that screaming. Some people have suggested holding her until she calms down, but as soon as I pick her up she points to my wife and I's bedroom and wants to go in there. Is she scared of the dark? I can't imagine anything in her room that would be scary, but you never know, I guess. She recently had a doctor's appointment, and physically she is fine. There have not been any changes in her life that I could think of that might have affected this, either. Sorry for the long rambling. I am writing this in the middle of the night, after yet another episode, and I am exhausted. Thanks in advance for any advice people might have!