Terapia Fotodinámica (PDT): qué es, cómo funciona y qué beneficios tiene en la piel
on September 29, 2025

Photodynamic Therapy (PDT): what it is, how it works and what benefits it has for the skin

TL;DR (in short):
Photodynamic therapy (PDT) combines a topical photosensitizer with a specific light source (laser, LED, IPL) to activate molecules that generate reactive oxygen species and selectively destroy damaged cells. It is used effectively in actinic keratosis , basal cell carcinoma , Bowen's disease , acne , rosacea , and photorejuvenation .

Index

  1. What is photodynamic therapy (PDT)?
  2. How it works: photosensitizers + light
  3. Most commonly used light sources in PDT
  4. Main benefits and clinical applications
  5. Safety and side effects
  6. Featured clinical cases
  7. General guidelines for aesthetic use
  8. Frequently Asked Questions
  9. References

1) What is photodynamic therapy (PDT)?

PDT involves applying a photosensitizer to the skin, which accumulates in the target cells (tumor or altered cells). After an incubation period, the area is illuminated with light of a specific wavelength , which activates the agent and produces reactive oxygen species .
Result: selective destruction of damaged cells and abnormal tissue, with minimal impact on healthy skin.

2) How it works: photosensitizers + light

The most commonly used photosensitizers are:

  • 5-ALA (aminolevulinic acid)
  • MAL (methyl aminolevulinate)
  • HAL (hexyl aminolevulinate)

All of them are transformed into protoporphyrin IX (pPIX) , which responds to red (630–635 nm) and blue (400–430 nm) wavelengths.

Ideal characteristics of a photosensitizer

  1. To locate themselves in the target cells.
  2. To be distributed evenly.
  3. Being lipophilic to penetrate barriers.
  4. To be eliminated quickly in healthy tissue.
  5. Activate with appropriate wavelengths.
  6. High production of reactive oxygen.
  7. Not toxic in the dark.

3) Most commonly used light sources in PDT

The most commonly used in aesthetic dermatology are:

  • LEDs (630–635 nm) – safe, easy to handle, allow treatment of large areas.
  • Blue light (418 nm) – useful for acne by activating bacterial porphyrins.
  • Intense pulsed light (IPL) – wide versatility in aesthetics.
  • Lasers (pulsed dye, argon, gold vapor, etc.) – more selective, but expensive.

👉 The literature highlights that red LED light (633 nm, ~105 J/cm²) is especially effective in rejuvenation, acne and actinic keratosis.

4) Main benefits and clinical applications

Indication Evidence Recommended light source
Actinic keratosis High efficacy (≈90%), low recurrence rates MAL + Red LED 633 nm
Superficial basal cell carcinoma High efficacy, ≈90% control Red light 570–670 nm
Bowen's disease Robust response in epidermal lesions Argon 488–514 nm / Red LED
Inflammatory acne Significant reduction in injuries (>50%) MAL + red LED (633 nm) or blue light (420 nm)
Rosacea Reduction of inflammation and telangiectasias MAL + red LED (633 nm)
Photoaging Improved texture, wrinkles, and pigmentation NG + red LED (633 nm, 37–105 J/cm²)

5) Safety and side effects

PDT is minimally invasive and well-tolerated, but the following may occur:

  • Pain or burning during irradiation.
  • Erythema (redness) and transient edema .
  • Formation of thin crusts .

Contraindications: photosensitivity, porphyria, porphyrin allergies, pregnancy (caution).

6) Notable clinical cases

  • Resistant inflammatory acne: 28-year-old woman treated with MAL + LED 418 nm → remission without flares at 6 months.
  • Advanced photoaging: 46-year-old woman with wrinkles and keratosis → improvement after 2 sessions with MAL + LED 633 nm.
  • Severe rosacea: 64-year-old male treated with MAL + 633 nm LED → clear reduction of inflammation and telangiectasias in 2 sessions.

7) General guidelines for aesthetic use (non-medical)

  • Preparation: deep cleansing, microdermabrasion or gentle peeling.
  • Photosensitizing application: 5-ALA or MAL, with occlusion for 1–3 hours.
  • Irradiation: Red or blue LED as indicated, adjusting fluence (37–105 J/cm²).
  • Recovery: Avoid direct sunlight and protect with high SPF.

8) Frequently Asked Questions

Is PDT the same as home LED phototherapy?
No. PDT requires a topical photosensitizer and is performed in medical settings. Home LED masks are based on photobiomodulation without photosensitizers .

How many sessions are needed?
It depends on the indication: from 1–2 sessions (actinic keratosis) to protocols of 3–5 (acne).

Is it suitable for aesthetic rejuvenation?
Yes, especially for improving fine lines, texture, and pigmentation associated with the sun.

Is it painful?
It may cause discomfort or burning during irradiation , but it usually disappears within 24 hours.

9) References

  • Mordon S, Martínez-Carpio PA, Vélez M., Alves R., Trelles MA Photodynamic therapy (PDT) in skin and aesthetics: procedure, materials and method based on our experience. Cir. plást. iberolatinoam. 2012; 38(3): 287–295.
  • Ruiz J., Rebollo N. Photodynamic therapy in dermatology. Dermatología Rev Mex 2009.
  • Issa MC et al. Photorejuvenation with MAL + red light. Dermatol Surg 2010.