Hot spots are usually due to food or environmental allergies. Food or environmental allergies can cause itching of the
skin and can occur anywhere
on the body.
However, the lesion could also have begun as a foreign body such as an awn, sticker, splinter, or wound, for example. These wounds can heal over but the inciting factor may still be there. Causing an abscess or infection.
The lesion could also be caused by ectoparasites, such as scabies mites, or fleas.