Deb's right.... my youngest son brought it home to me from school a few years ago. At first, I thought we'd contracted it from one of my rats. He was a new member of the family at the time and was a double rex, complete with very scruffy fur and balding patches.
Long story short, my son's case cleared right up with the first cream the family doctor prescribed, but mine didn't. It took going to a dermatologist to find out that (1) it isn't a good idea to use the kind of anti-fungal cream that also contains a second ingredient (I believe it was a corticosteroid) for soothing the area because the second ingredient actually provides exactly the perfect environment for the fungus to thrive in, even while it seems to suppress the visible symptoms; and (2) we are far more likely to contract ringworm/fungal infections from other people; not from our pets. And although it is possible to contract them from some animals, the dermatologist told me I would have been more likely to get it from my cats (even though they are indoor cats!) than I would have been from my rats.
I ended up having to take Lamisil tablets to get rid of mine. It had gone on for months and had spread all over my chest, neck, and half my face (!!!), as well as portions of my arms and belly. Yuck! And to think my son just happened to get it from some other kid at school and only ever developed a couple of small spots. The weirdest part was, although I had such a nasty case of it that went on for months before I got the right treatment for it, my hubby, our other son, and all our critters never did develop it! Guess I'm just super-sensitive to stuff like that. Lucky me!