This is a phase 4, multi-centre, randomized, two group, open label, active controlled, parallel group, 17 week trial.

All subjects who qualify for this trial are to have 4 to 8 clinically typical, visible and discrete AK lesions within a contiguous 25 cm2 treatment area on the face or scalp.

Eligible subjects will be randomised in a 1:1 ratio to the following treatment groups:

• Treatment Group A: Ingenol mebutate gel 0.015%, once daily for 3 consecutive days for the first treatment course. At 8 weeks after treatment initiation, subjects who present with existing AKs or newly emergent AKs in the treatment area will receive one more treatment course of ingenol mebutate gel 0.015%, daily for 3 consecutive days.
• Treatment Group B: Diclofenac sodium gel 3%, (0.5 grams), twice daily for 90 days.

Inclusion Criteria:

1. Following verbal and written information about the trial, subject must provide informed consent documented by signing the Informed Consent Form (ICF) prior to any trial related procedures
2. Subjects with 4 to 8 clinically typical, visible and discrete AKs within a contiguous 25 cm² treatment area on the face or scalp

Exclusion Criteria:

1. Location of the selected treatment area:

• on the periorbital skin
• on the perioral skin/around the nostrils
• within 5 cm of an incompletely healed wound
• within 10 cm of a suspected BCC or SCC or other neoplasia