The purpose of this study is to find out the effectiveness of ingenol mebutate compared to cryotherapy (freezing of the tissue) for the treatment of face and scalp 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