What sort of rash or ailment has my son caught?

I recently moved from Texas to Colorado. My son, 10 years old has developed a rash in the creases of his arms and on one of his legs. I have been applying a topical ointment. I believe it started after being around a friends pet. It is not ringworm. the itching is not intense or constant. They seem to be more pinkish or his skin color. Does this sound more like plant or contagious infection. He does not carry any other symptoms really.