Hi Erika,
I contacted your local Extension office to get information about UGA's plant disease lab(s). I can't diagnose the problem from your pictures, and I want you to submit a sample for an accurate diagnosis. I am concerned that it could be either pythium or brown patch, but an accurate diagnosis is important to determine management strategies.
I will be in touch when I hear back from the DeKalb County Extension office.
Best regards,
Sandy

Erika,
Here is the response I received from your county Extension office:
The resident can come into our office to bring her sample in and we can send it off for her. There is a bit of paperwork involved, and the cost will be $14.
Hope this helps,
Ashlee Borders, Office Assistant UGA DeKalb County Extension
4380 Memorial Drive Ste. 200
Decatur, GA 30032
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Here are instructions from Penn State's Plant Disease Clinic for collecting turfgrass samples:

• Please do not send completely dead turfgrass
• Collect two or three squares (each 3x3 inches square), with at least
  one inch of attached soil and roots, from the edges of affected areas
• Include both dying and apparently healthy plants
• Wrap each sample in one thickness of slightly dampened newspaper or
  paper toweling, then in dry newspaper. Aluminum foil can also be used to
  wrap turf samples
• Turfgrass diseases can be very difficult to diagnose accurately, so include as much information about the problem as possible
• Photographs of the lawn are also very helpful.

Best regards,
Sandy