Ingenol Mebutate Compared to Cryotherapy for the Treatment of Skin Lesions

Inclusion Criteria: * Male and female subjects between 18 and 89 years old. * Have at least a total of 10 non-hypertrophic actinic keratoses (AKs) on the face and scalp * The subjects are in good health * The subjects have the willingness and the ability to understand and provide informed consent for the use of their tissue and are able to communicate with the investigator Exclusion Criteria: * Subjects under 18 years of age and over the age of 89 * Subjects who are pregnant or lactating * Subjects with sensitivity to cold * Subjects with use of topical medications such as corticosteroids, alpha-hydroxyacids or retinoids 2 weeks before study entry * Subjects who received previous treatment of target AKs * Subjects whose target treatment area was within 5 cm of an incompletely healed wound or within 10 cm of a suspected basal-cell or squamous-cell carcinoma * Subjects with use of medications or other treatments that could interfere with evaluation of the treatment area within 2 months before study entry (e.g., topical medications, artificial tanners, immunosuppressive medications, immunomodulating agents, cytotoxic drugs, ultraviolet B phototherapy, other therapies for actinic keratoses, or oral retinoids) * Subjects who are unable to understand the protocol or to give informed consent