Diffuse actinic damage is typically treated with field therapy (4) that involves the use of topical 5-FU. Patients are advised to apply the cream twice daily for 2-4 weeks (5). However, many patients note misunderstanding with these instructions (6). Typical follow up has included telephone based grading and in person follow up (5). However, a return visit to the clinic can be both burdensome to the patient and fill up the clinic with follow up appointments instead of allowing the appointment slot to go to examination of a new patient, thereby reducing access to care for other patients. Telephone conversations are not based on a physical exam and thus do not allow for objective evaluation of the treatment area. For this reason, the researchers seek to use mobile phone photography to evaluate patients with actinic keratoses on topical 5-FU treatment.