Efficacy and Safety of Ingenol Mebutate Gel for Actinic Keratosis Applied on Large Area on Face, Scalp or Chest

Inclusion Criteria: Subjects with 5 to 20 clinically typical, visible and discrete, actinic keratosis (AKs) non-hyperkeratotic and non-hypertrophic AKs within a selected treatment area of sun-damaged skin on either: * The full face * The full balding scalp * A contiguous area of approximately 250 cm2 on the chest Exclusion Criteria: * Location of the treatment area (full face, full balding scalp or chest) within 5 cm of an incompletely healed wound or within 5 cm of a suspected basal cell carcinoma (BCC) or squamous cell carcinoma (SCC). * Previously assigned treatment in this clinical trial or previously participated in a clinical trial in the LEO clinical programme on ingenol mebutate gel for larger treatment areas. * Treatment with ingenol mebutate gel in the selected treatment area within the last 12 months. * Lesions in the treatment area that have: atypical clinical appearance (e.g. cutaneous horn) and/or, recalcitrant disease (e.g., did not respond to cryotherapy on two previous occasions).