Anthony Rossi, MD, FAAD, FACMS, on the Practical Benefits of Photodynamic Therapy

Photodynamic therapy (PDT) has long been used to treat actinic keratoses (AKs), but its practical advantages in the clinic are increasingly shaping how dermatologists approach field-directed treatment. According to Anthony Rossi, MD, FAAD, FACMS, PDT offers a clinician-controlled alternative that can simplify treatment while improving adherence.

Rossi notes that while lesion-directed approaches such as cryotherapy remain useful for isolated lesions, they may not address the broader landscape of actinic damage. “Yes, we can freeze a single spot,” he said, “but we really need to think holistically about the whole picture.” PDT allows clinicians to treat visible and subclinical lesions across an entire field of photodamaged skin.

One key advantage is patient compliance. Topical field therapies such as 5-fluorouracil and imiquimod can produce inflammatory reactions—including erythema, crusting, and peeling—that persist for weeks and often discourage patients from completing treatment. In contrast, PDT is performed in-office using a photosensitizing agent such as aminolevulinic acid followed by light activation, allowing clinicians to control dosing and ensure the treatment is completed as intended.

“With PDT, patients come in, have the procedure, and then go home and heal,” Rossi explained. Most patients experience redness, swelling, and crusting that resolve within about five to seven days. Topical regimens, by comparison, may require 2 to 4 weeks of continuous application, often leading to interruptions or incomplete courses.

Rossi also noted that cost-effectiveness analyses that incorporate adherence can shift the value equation. When compliance is factored into treatment outcomes, PDT can compare favorably with repeated cryotherapy sessions or partially completed topical regimens.

Beyond AKs, Rossi uses PDT in a variety of settings. He has applied the therapy to the arms, legs, trunk, and even more sensitive areas such as the genital region in select cases involving superficial malignancies. Cosmetic improvements are also frequently reported by patients, who often notice smoother or more refreshed skin after healing.

Technological advances may further expand PDT’s clinical utility. Larger red-light panels now allow dermatologists to treat broader areas—such as both arms or an entire back—in a single session. Rossi has also used red light off-label for inflammatory acne, where activation of the photosensitizer can help reduce sebaceous gland activity.

Even outside of PDT, red light devices may have additional roles in dermatology practices. Rossi often uses them to support photobiomodulation and healing after procedures such as laser resurfacing, and similar light therapies have been used in oncology settings to manage inflammatory conditions like oral graft-versus-host disease.

For clinicians considering integrating red light systems into their practice, Rossi suggests thinking beyond PDT alone. “If you have a red light device,” he said, “you should be using it for more than one purpose.”