Can telogen effluvium be triggered by twilight anesthesia, general anesthesia, or blood draws?

Many things may be "possible" but it is not very "probable". It is best to see a doctor for an examination to understand your hair loss issue.

In my opinion, the normal course of telogen effluvium is rapid shedding, approximately two to three months after the causation event. The most common triggers for telogen effluvium include thyroid dysfunction, childbirth, fever,crash diets, iron deficiency, PROLONGED anesthesia and illness or psychological stress. If you have transitory episodes of shedding lasting several weeks with no apparent cause, it is possible that you  have chronic telogen effluvium. This usually affects the whole scalp without an apparent etiology. Symptoms of the scalp are more common with chronic telogen effluvium. You should seek a hair expert. Have them do a good evaluation with magnification, pull test and a history. You may need a biopsy and blood work. Hope this helps. Good luck.

Without knowing more and seeing your scalp, I can't conclude what could be happening. It's unusual to experience TE from twilight anesthesia and blood draws. Not impossible but not common. I'm always following blood tests in our TE patients and I've not seen a consistent phenomenon of blood draws triggers sheds. Yes, those with TE do appear to be slightly more sensitive to various triggers. A true TE lasts many weeks rather than days (unless it's chronic telogen effluvium "CTE" which has nothing to do with blood draws and twilight anesthesia).

What you are describing probably resulted from your endoscopy and anesthesia. This will take a course of up to 6 -8 months when the hair will probably return. Be patient and wait it out.