I am a writer with a hypothetical question: can excessive amounts of spice cause damage to the throat? I've heard of it happening with sugar+soda etc.

Answer eludes me. Spicy food as well as soda cause gerd to get worse, stimulates acid in the stomach and if it results in reflux laryngitis, the answer is yes. I like to sing, and I perform, and I love spicy food, including wasabe, etc., and I have been fine. In this case, I may not be the best to answer it, but my answer, if there is no problem, enjoy life. Lol.