I picked Percy up from a Petsmart. I honestly intended to go with a rat rescue to honor my animal shelter roots, but I played with him on a whim and it was akin to being hit by a spiritual truck. I was a gonner and had to have him. He bloomed into an intelligent, feisty, and adventurous companion. His favorite thing to do was follow you around the house in his over-sized hamster ball. He never sat still unless it was to gobble a dried cherry.
In the space of a weekend road trip when he was about a year and a half old, I came home to discover he had scratched all the fur off behind both his front legs. There were quarter sized patches of scabs while the rest of his fur remained glossy and healthy. His upper lips were also swollen. A skin scraping at the vet turned up mites, so we started treatment for both rats in our house (each were already housed individually). The vet also prescribed antibiotics in an effort to treat the lip. Then more concentrated antibiotics because Percy was sneaky about spitting the doses out. Then a different combination of concentrated antibiotics because there were hints of improvement. A ring worm test turned up negative.
Meanwhile, the other rat in the house (who kind of became the default "control" rat to rule out infectious disease even though I kept them very separate) continued happy and healthy and Percy's scabby patches grew and his lip became even more swollen and started scabbing over. He started loosing weight so I switched his diet to soft baby food in an effort to keep weight on him, which he devoured.
Side note that did not sit anywhere else, but might be useful to somebody: I had a cat in high school who was also diagnosed with an autoimmune disease where prednisone was the treatment. Albert presented with the same swollen upper lip as Percy, but instead of raw patches on his shoulders Albert's paws would bleed. After several years Albert's end was also euthanasia. I noticed and worried about similarities early on in Percy's illness, but the vet seemed quite convinced antibiotics were the best initial treatment in the hopes the illness wouldn't require steroids.
Ugh. I have been trying for weeks to think of an adequate closing to this post, to give some sort of closure beyond e-hugs and love and sympathy to anybody else going through this. I even thought about not posting it because why dwell on the end when there was so much good before that? Somehow I do not think Percy would understand my brooding. Rats are the greatest teacher of zen I know. Falling in love with a creature who has a big personality and naturally short lifespan only serves as a reminder to stay anchored in the present moment and enjoy the good while it exists alongside you.