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How Do I Care for My Skin After PDT?

Sun avoidance, gentle wound care, and a realistic healing timeline

Medically reviewed by Dr. Steven Q. Wang, MDLast reviewed

Bring a printable list of questions to your appointment, or share this page with someone who needs it.

Download printable checklist (PDF)

Introduction

The days right after a photodynamic therapy (PDT) session matter almost as much as the treatment itself. A photosensitizing agent — ALA or MAL — was applied to your skin and activated with light to destroy sun-damaged cells, and some of that solution stays active in your skin for a short time afterward. How you protect and care for the treated area during this window shapes both your comfort and how smoothly your skin heals.

This article walks through exactly what to do — and what to avoid — in the first 24 to 48 hours, gentle care for the following one to two weeks, a general timeline of what healing looks like, and the specific signs that mean it's time to call your dermatologist.

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The First 24–48 Hours: Strict Light and Sun Avoidance

This is the single most important part of PDT aftercare. The photosensitizing agent doesn't fully clear from treated skin the moment your light session ends — it remains active for a period afterward. If that skin is exposed to sunlight, or in some cases strong indoor light, during this window, it can trigger an exaggerated reaction: intense redness, swelling, and blistering well beyond what the treatment alone would cause.

  • •Stay indoors and away from windows for the first 24 to 48 hours, as directed by your dermatologist — some regimens call for a shorter or longer window depending on the photosensitizer used.
  • •If you must go outside, cover the treated area completely with clothing, a wide-brimmed hat, or a scarf — broad-spectrum sunscreen alone is not considered reliable protection during this early window.
  • •Avoid bright indoor light sources your dermatologist flags as relevant, and ask specifically about car windows, since UV light passes through glass.
  • •Once this early window has passed, resume diligent daily sun protection — the same sun-smart habits that help prevent new actinic keratosis from forming.

Gentle Daily Care

  • •Cleansing: wash with lukewarm water and a mild, fragrance-free cleanser using just your fingertips — no washcloths, brushes, or scrubbing.
  • •Moisturizing: apply a plain, fragrance-free moisturizer or the ointment your dermatologist recommends several times a day to keep the skin from drying and cracking.
  • •Cool compresses: a clean, cool (not icy) damp cloth held gently against the area can ease stinging, burning, or swelling for the first day or two.
  • •Ask before using any over-the-counter pain reliever or antihistamine for discomfort.

What Not to Do

  • •Don't pick, scratch, or peel at crusting or flaking skin — let it shed on its own to avoid scarring or infection.
  • •Skip harsh products: retinoids, exfoliating acids, astringents, and fragranced skincare should wait until the skin has fully healed.
  • •Avoid makeup over open or weeping skin until your dermatologist says it's safe.
  • •No swimming, saunas, or hot showers that could irritate healing skin in the first few days.

A Rough Healing Timeline

Healing pace varies by person and by how much skin was treated, but most people follow a similar general pattern over one to two weeks:

  • •Days 1–2: redness, warmth, swelling, and stinging or burning — often most intense the evening of treatment and the following day.
  • •Days 3–5: skin becomes drier and tighter; peeling or light crusting typically begins as damaged cells shed.
  • •Days 5–10: visible flaking and crusting continue to resolve; the skin underneath may look pink or slightly darker than usual (this fades with time).
  • •Week 2 and beyond: most visible reaction has settled; residual pinkness can linger longer, especially in fair skin.

When to Contact Your Dermatologist

Most reactions after PDT are expected and self-limited, but call your dermatologist's office if you notice:

  • •Signs of infection: spreading redness, warmth, increasing pain after the first couple of days, pus or cloudy drainage, or fever.
  • •Unusual or severe blistering — some mild blistering can occur, but large, painful, or widespread blisters warrant a call.
  • •Bleeding that won't stop with gentle pressure.
  • •Symptoms that are getting worse rather than gradually improving after the first several days, or healing that seems to be stalling out.

A clinical study of patients treated with PDT for facial actinic keratosis found that most people experience some degree of redness and mild pain within the first 48 hours, and that a stronger inflammatory reaction is generally a sign the treatment is working on more heavily sun-damaged skin — not a red flag on its own. Still, if anything feels off, it's always reasonable to call rather than wait and worry.

What to Ask Your Doctor

Download printable checklist (PDF)
  1. Exactly how long should I avoid sunlight and bright indoor light after my treatment?
  2. What products should I use to clean and moisturize the treated area?
  3. What level of redness, swelling, or crusting is normal for me, and what would be too much?
  4. Is there anything I can take or apply for discomfort?
  5. When can I resume my normal skincare routine and wear makeup again?
  6. What symptoms should prompt me to call your office right away?

Conclusion

The first two days after PDT are about protecting your skin from light while the photosensitizer clears; the following one to two weeks are about gentle, patient wound care while the treated cells shed and healthy skin takes their place. Most people move through this predictable process without complications.

Follow your dermatologist's specific instructions, resist the urge to pick at healing skin, and reach out promptly if anything looks or feels worse than expected. A little extra care in this window goes a long way toward a smooth recovery.

Sources

Clinical Guidelines & Peer-Reviewed Literature

  • Eisen DB, Asgari MM, Bennett DD, et al. Guidelines of care for the management of actinic keratosis. J Am Acad Dermatol. 2021;85(4):e209-e233. PubMed
  • Wiegell SR, Wulf HC, Szeimies RM, et al. Daylight photodynamic therapy for actinic keratosis: an international consensus. J Eur Acad Dermatol Venereol. 2012;26(6):673-679. PubMed
  • Shen AS, Heusinkveld LE, Updyke A, et al. Painless photodynamic therapy for facial actinic keratoses: a retrospective cohort study of the post-treatment inflammatory response. Photodiagnosis Photodyn Ther. 2024;45:103838. PubMed

Patient Resources

Disclaimer: This page is for educational purposes only and is not a substitute for professional medical advice. Always follow the specific aftercare instructions your dermatologist gives you, and contact their office with any concerns during recovery.

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