Different response-to-therapy rates on the basis of the treated anatomical sites. 1: complete response to therapy in a patient with AK on left upper prolabium. Clinical grade decreased from III (a, pretreatment) to 0 (b, posttreatment); dermoscopic grade decreased from III (c, pretreatment) to 0 (d, posttreatment). 2: complete response to therapy in a patient with AK on left forearm. Clinical grade decreased from III (a, pretreatment) to 0 (b, posttreatment); dermoscopic grade decreased from III (c, pretreatment) to I (d, posttreatment). 3: lack of response to therapy in a patient with AK on the scalp. Clinical and dermoscopic grade remained stable at III (a-c, pretreatment; b-d, posttreatment).