This is a double-blind, multicenter, long-term follow-up study. The primary purpose of this study is to assess recurrence of Actinic Keratosis in participants treated with Methyl aminolevulinate hydrochloride (MAL) 16.8 percent (%) cream (CD06809-41) or vehicle cream in the treatment of thin and moderately thick, non-hyperkeratotic, non-pigmented actinic keratosis of the face and scalp when using daylight photodynamic therapy (DL-PDT), for participants achieving complete response of treated lesions at Final Visit in Study RD.06.SPR.112199 (NCT04085367).
