As much as I have spent way too much of my life becoming educated in this area, I'm not actually sure everybody has a definable trigger. After all, it is an autoimmune disorder. I guess I just found out that I'm one of the lucky ones that has figured out what provokes mine.

For anybody that has suffered, also be aware that a universal trigger for psoriasis sufferers is anything with blue/purple dye. They are safe for external use, but psoriasis is broken skin which makes it introduce directly into the bloodstream, and the number one side effect of those dyes is eczema, psoriasis, and dry skin.

E: I have come to believe without evidence to back it up that dyes are actually a major contributor to the general belief that lip balms are "addictive".