I have a red, inflamed belly button that has a discharges and gets crusty skin, what causes this?

Not sure but: Difficult to say for sure but hernias can occur in area and become irritated, old scar tissue or granuloma from prior surgery, rarely a sinus or fistula especially in crohn's disease, tumor or tumor related lymph node occur there, eczema, maceration from obesity, yeast infection. Best to have examined, a scraping for exam under microscope, culture and possibly an ultrasound or ct scan. Get an exam.