Practical Decisions Behind PDT for Actinic Keratosis

In a continued conversation with Dermatology Times, Michael O’Donoghue, MD, discussed how he approaches photodynamic therapy (PDT) for patients with actinic keratosis (AK) in routine clinical practice. Drawing on his experience in a busy dermatology practice in Northwest Indiana and the Chicago area, O’Donoghue focused on the practical decisions that shape how PDT is used outside of clinical trials.

A key point in the discussion was that PDT is not a “one-size-fits-all” treatment. O’Donoghue explained that how PDT works, and how patients experience it, can vary widely depending on where it is used on the body. Areas such as the face and scalp often respond more predictably, while sites like the arms can be more challenging and may require adjustments to the treatment approach. These differences are something clinicians quickly recognize when treating patients with widespread sun damage.

Much of the conversation centered on incubation time, or how long the photosensitizing medication is left on the skin before light activation. O’Donoghue noted that while traditional protocols often recommend specific incubation periods, real-world practice is more flexible. In his experience, some patients do well with shorter incubation times, particularly if they have sensitive skin or are concerned about discomfort and downtime.

For other patients, especially those with more extensive or thicker lesions, longer incubation may be helpful to improve results. O’Donoghue also described situations in which incubation may be minimal or skipped altogether, with treatment proceeding shortly after application. These decisions are typically guided by prior patient experience, treatment goals, and tolerance rather than rigid protocols.

Patient preference plays a major role in this decision-making process. O’Donoghue emphasized that patients differ in how much redness, peeling, or discomfort they are willing to accept. Some are motivated to address significant sun damage in a single, more intensive treatment, while others prefer gentler approaches even if that means additional visits. Taking time to align treatment plans with patient expectations can improve satisfaction and adherence.

Throughout the discussion, O’Donoghue highlighted the importance of clinical judgment and flexibility when using PDT. Rather than viewing it as a fixed procedure, he described it as a tool that can be adjusted to fit individual patients and practice settings.

Overall, the conversation reflects how PDT is commonly used in everyday dermatology care—guided by experience, patient input, and an understanding of how different skin areas respond to treatment. O’Donoghue’s insights offer a practical look at how clinicians tailor PDT to meet the needs of patients with actinic keratosis in real-world settings.