Photodynamic Therapy (PDT): Photosensitizer-Driven Deep Antimicrobial Work
The Triad
PDT = photosensitizer + oxygen + specific light. Topical photosensitizers (ALA/MAL) concentrate in high-metabolism cells (sebocytes, abnormal keratinocytes, C. acnes); red or blue light activates them into singlet oxygen, selectively destroying targets. The essential difference from plain LED work (no sensitizer, far lower energy): see LED therapy.
Main Indications
- Moderate-severe acne: sebaceous suppression plus antimicrobial action — a medical option for drug-resistant cases.
- Actinic keratoses and precancers: the dermatology classic (medical path).
- Other lesions: adjunct for selected proliferative and vascular conditions.
Flow and the Photophobia Window
- Application: sensitizer under occlusion 1-3 hours per protocol.
- Illumination: red or blue light with marked burning/stinging.
- Reaction phase: redness, scaling and purging for 3-7 days — expected.
- Strict photophobia: complete light avoidance 24-48 h post-illumination (indoor and screen light included) — the management demand separating PDT from every routine program; missing it worsens reactions.
Facility Requirements
- A medical program: physician prescribing and compliant drug handling.
- A light-shielded zone (blackout, windowless or highly protected) plus briefing flow.
- Reaction-phase care SOP and follow-up (an intensified aftercare).
FAQ
PDT vs ordinary red-blue acne light?
The sensitizer is the watershed: plain light is gentle, multi-session, home-continuable; PDT is powerful, fewer sessions, heavy reactions, medically managed — different tool classes.
How strict is the photophobia?
Execute as “complete darkness”: heavy curtains, screens off, no going out. Gradual return after 48 hours, then a week of strong sunscreen.