Yesterday squido took Snickers to Alameda East and got to see Dr. Fitzgerald, a specialist for small rodents like Chinchillas and Guinea Pigs.
Dr. Fitz checked in several different ways for mites, fungus and ringworms, even though he said it didn't look at all like any of those. Parasites tend to cause at least some skin irritation, which she has none. They also tend to cause progressively worse skin irritation, and would have led to extreme illness and probably death in the time we know she has had the hair missing.
He poked around at her belly, which he said was quite obviously enlarged and lumpy. This is almost always caused in older, female guinea pigs by hormonal problems resulting from a tumor. She has swollen, enlarged nipples that is also almost always a sign of an adrenal gland tumor. The pattern of hair loss (literally the locations of it) was also classic for adrenal gland tumor, which in the end was his probable diagnosis.
It's not the sort that is going to spread to her entire body, because it simply would have by now and she would have lots of other horrible symptoms. An ultrasound would confirm it, but he says he is 95% sure and any sort of tumor it could be isn't hurting her and won't effect her lifespan.
In summary, she has a tumor...if it grows it will instantly start to hurt her, and she will immediately stop eating...at which point the best thing to do for her is to put her to sleep. He doesn't think that will be anytime soon, however.
In the mean time, I am finding amusement and joy preparing her little plates of mixed vegetables. Most days I hand feed them to her one at a time. Some days she is a little spastic and will snatch the veggie from my hand and run in her pigloo. When she isn't feeling social like that, she gets the whole plate to enjoy at her own pace.
Last night she spent a lot of time on squido's lap, then spent time on my computer desk. She seems to not care about the cats and Badger remains deathly afraid of her when face to face.