Which layer of the skin does chickenpox effect?

Complicated Skin. The simple answer is the epidermis which is the top layer. Chickenpox causes the epidermal cells to ballon which forms a classical blister. See pic. But the epidermis is composed of 4 or 5 layers: cornified layer, clear/translucent layer, granular layer, spinous layer and basal/germinal layer. Varicella affects the spinous layer. Thanks for the difficult question!