By a combination of observation and deduction, I have discovered the cause of Alzheimer's and some related diseases.
Lichen planus/sclerosus is an infection with a tiny mite which is exquisitely adapted to the human host. It is commonly at home in the biome of adults’ skin in our culture, and commonly without serious consequences. Like many other creatures in the common human biome of our culture, it becomes dangerous in certain conditions of the host environment. This creature can, in the right circumstances, cause the injuries of lichen planus/sclerosus, including wasting/erosion, open sores, pain, etc. This creature can colonize the sinuses, eye sockets and palate, and thereby reach the brain. Alzheimer’s is lichen planus of the brain.
MK Bretsch, 2015