How long before chickenpox could appear after exposure?

10-21 days. The standard "epidemiological" answer is that chickenpox illness begins within 10-21 days after exposure. It often begins with cold symptoms and fever 1-2 days before the blisters appear. Get homeopathic rhus tox 30c or 200c and give 2 pellets 3-4 times a day as soon as the blisters appear. It reduces itching and speeds crusting over. It is wonderful!
A week. Fever, then the rash. I had 3 of my kids develop chickenpox within a week of each other.