Has he had a cold, for instance. Kids with ear infections often have had a cold in the previous week or so. In terms of what you see, it sounds like an infection that is either an external otitis where he now has drainage, or the tympanic membrane has ruptured. I would take him in for an evaluation and probably an antibiotic. My mother told me that ear infections are caused by a virus.
Viruses can definitely cause ear infections but so can bacteria.
Or a viral infection such as a cold, can create the conditions for a bacteria to get a hold and set up an infection. When people have dry, flaky, itchy skin around their outer ear, it may feel better if lubricated. First, during an acute infection, increase vitamins a, b-complex, c, e, zinc and evening primrose oil to boost the immune system. Some of the alternative remedies that might help during the infectioin are heat or icepacks to relieve pain, calming teas such as chamomille, hops, or passion flower. For the child with lots of allergies, eliminating milk, wheat, corn, oranges, eggs, and peanuts might help but the parent needs to be careful not to do these things for a prolonged time causing nutritional deficiencies in the child.