How effective is photodynamic therapy for actinic keratosis?

An actinic keratosis is a sun-damaged patch that may feel rough or scaly. Photodynamic therapy applies a light-sensitive medicine to the affected skin and activates it with a chosen light source. The reaction targets abnormal cells, while the surrounding skin may also be treated when there is a broader field of sun damage.

Effectiveness is not judged by immediate appearance. Redness, warmth, crusting, and sensitivity can occur before healing. A lesion that remains thick, tender, bleeding, or scaly after healing should be reviewed, since it may need another treatment or a biopsy.

Before treatment, have each rough or changing spot examined so the diagnosis and treatment area are clear. Tell the clinician about medicines or conditions that make you sensitive to light. After treatment, follow the specified light-protection period, keep the area clean as advised, and do not remove crusts by force.

Use regular sun protection on exposed skin and return for the planned review. New rough patches can appear in other areas even when the treated field has healed, so mention them rather than treating every mark as the same problem.

Contact the clinic if swelling, pain, blistering, discharge, or redness becomes more severe or spreads. Arrange prompt assessment for a spot that grows, becomes hard or very tender, bleeds repeatedly, or fails to heal after treatment, because these changes can signal a lesion needing closer evaluation.

Which lesions will you treat, and is a biopsy needed for any thick or changing spot? Would field treatment suit my pattern of sun damage? What reaction should I expect, how long should I protect the skin from light, and when will you reassess the area?