Top 5 Questions People Ask Before Photodynamic Therapy

1. Is PDT effective for actinic keratosis and sun-damaged fields?
2. What does PDT feel like — will it be painful?
3. How many sessions do I need and how long is recovery?
4. Is PDT suitable for Bowen’s disease or superficial BCC?
5. Can PDT treat acne — and is it better than other options?

What Is Photodynamic Therapy — and How Does It Work?

PDT pairs a photosensitiser (a cream or solution that preferentially accumulates in abnormal cells) with a specific light (often red). After an incubation period, light activation triggers reactive oxygen species that selectively destroy target cells, while leaving most normal skin intact. Because actinic damage often spans visible and subclinical areas, PDT is ideal for field therapy (treating a whole zone such as forehead or scalp).

At Skinhorizon, we use medical-grade systems such as the GME PDT platform with carefully defined energy and timing parameters. Your consultant may recommend conventional red-light PDT or daylight PDT (dPDT) in suitable seasons/skin types.

Who Is (and Isn’t) a Candidate for PDT?

• Excellent candidates: multiple actinic keratoses (especially on face/scalp), “field cancerisation,” biopsy-proven Bowen’s disease, and selected superficial BCC when criteria are met.
• Acne protocols: inflammatory acne not responding to standard care may benefit from PDT within our acne treatment pathway — parameters are individualised.
• We may defer or choose alternatives if you have porphyria/photosensitivity disorders, cannot avoid sun after treatment, have active infection, are pregnant/breast-feeding (risk/benefit), or if lesion depth suggests surgery is superior.

Diagnosis first: dermoscopy and, where needed, skin biopsy & analysis confirm suitability before PDT.

PDT Step-by-Step: What to Expect on Treatment Day

1. Assessment & mapping: dermoscopic exam; photos; mark treatment field(s); discuss alternatives (lesion care options).
2. Preparation: gentle curettage/skin prep to improve photosensitiser penetration; apply the agent; cover/incubate (typically 1–3 hours depending on protocol).
3. Activation: under the medical-grade lamp (commonly red light) for minutes; you may feel heat/stinging — we cool and pace as needed.
4. Immediate aftercare: soothing barrier products; strict light avoidance for 48 hours; written home-care pack.
5. Follow-up: review healing and decide on session 2 (often 1–2 sessions total for AK/Bowen’s) or adjunct care.

Downtime, Sensations and Aftercare

Expect stinging/burning during light exposure that settles once the lamp stops. Over the next few days the area is red, tight and may form crusts/peeling as damaged cells lift away. We provide a simple regimen (cleanse, barrier, SPF) and a 48-hour strict light avoidance rule. For dPDT, instructions differ and are given seasonally.

• 48 hours: avoid direct sun/daylight and intense indoor light; wear a brimmed hat if you must be outdoors.
• 1–2 weeks: crusts shed; pinkness gradually fades. Make-up is usually fine once skin is intact.
• Contact us promptly for spreading redness, increasing pain, or concern about infection.

How Well Does PDT Work — and What Are the Alternatives?

For the right indications, PDT offers high clearance rates with good cosmetic outcomes, particularly across fields of sun damage (forehead, scalp). Compared with single-spot treatments (e.g., freezing), PDT treats both visible and subclinical lesions across the whole area, helping reduce recurrence in that field.

Alternatives We Also Offer

• Cryotherapy (freezing) for isolated AKs; quick but spot-focused.
• Topical field therapy (e.g., 5-FU or imiquimod) — more at-home downtime; effective in specific cases.
• Curettage & cautery / excision for thicker lesions or when histology is required; performed with our electrosurgical unit.
• Energy devices for texture/vascular issues accompanying sun damage: fractional CO₂ laser, vascular/pigmentation laser.

For acne, PDT can suppress the sebaceous unit and inflammation. We weigh this against medical options and low-downtime procedures in our acne treatment pathway.

Daylight PDT vs Conventional PDT

Conventional PDT uses a clinic lamp and is more controlled; it can sting during activation but gives predictable energy. Daylight PDT uses ambient daylight to activate the photosensitiser; it’s generally less painful and suits large facial/scalp fields in the right season. Suitability depends on weather, skin type, and your ability to follow sun-safety instructions on the day.

Safety, Risks and How We Reduce Them

PDT is generally safe when diagnosis and selection are correct. Expected effects include redness, swelling, crusting and photosensitivity. We screen for photosensitising conditions or medicines, guide pain control during activation, and provide a clear escalation route. Rare risks (infection, scarring, pigment change) are discussed at consent; for cancer care, we define follow-up to monitor clearance.

• Diagnostics first: dermatoscopy and, if needed, biopsy confirm indication.
• Field care: emollients, barrier repair and SPF reduce post-PDT irritation and help long-term prevention.
• Surveillance: we advise periodic skin checks; see skin cancer info and ABCDE mole check.

Your Consultant-Led PDT Pathway (Maida Vale)

1. Consultation: medical history, medication review, skin exam and photos.
2. Decision: PDT vs cryotherapy, topical field therapy or surgery depending on lesion type, site and goals.
3. Treatment: conventional or daylight PDT protocol with clear instructions.
4. Aftercare: written day-by-day plan and red-flag checklist.
5. Review: assess clearance; plan session 2 (if needed) or maintenance (SPF, skincare, adjuncts).

Areas we serve: Maida Vale (Central/West London hub), St John’s Wood, Paddington, Hampstead, North West & North London.

FAQs: Photodynamic Therapy (PDT) in London