Brin,

What's the color and consistency of the discharge? Is it acrid or bland? What's the child like otherwise? what's his body type? His personality? Thirst? Food desires? Is he warm or chilly? When did you first notice this phenomenon? What was happening in his life around that time, including illnesses he may have not completely recovered from, vaccinations, etc.
Does he perspire in any particular place?
How is he affected by weather?

Snoopy