This is caused by Azalea Lace Bugs!
This information came from the publication Control of Common Pests of Landscape Plants
Lace bugs get their name from the appearance of the area behind their head and wing covers. The area forms a lace like covering over the body of the insect. They are 1/8 to 1/4 inch in length and are partially transparent. Lace bug damage appears on the upper leaf surface as white to yellow chlorotic spots. The lower leaf surfaces will be cluttered with black spots and the old cast skins of immature lace bugs. Initiating control in the spring between March and May will reduce problems later in the season.
To find more id and control information on this or other landscape insects read the UGA publication Control of Common Pests of Landscape Plants
To find pesticide recommendations and use information visit the Georgia Pest Management Handbook.