Red Light Therapy for Actinic Keratosis & Skin Lesions

This page covers three common skin conditions that people frequently search in relation to red light therapy: actinic keratosis, seborrheic keratosis, and keratosis pilaris. Despite sharing the word “keratosis” (which simply means an abnormal thickening of the skin’s outer layer), these are fundamentally different conditions with different causes, different risks, and very different relationships to light-based treatment.

The critical distinction upfront: red light therapy as used in home devices is not the same as the light-based treatment used clinically for actinic keratoses (photodynamic therapy). Confusing the two could be dangerous. This page explains the difference clearly.

Actinic Keratosis (Solar Keratosis)

What It Is

Actinic keratoses (AKs) are rough, scaly patches on sun-damaged skin caused by years of cumulative ultraviolet exposure. They appear most commonly on areas with chronic sun exposure — the face, scalp (especially in bald or thinning-haired individuals), ears, forearms, and backs of hands.

AKs are classified as pre-malignant lesions. Approximately 5–10% of untreated AKs progress to squamous cell carcinoma (SCC), a form of skin cancer. This is why dermatologists take AKs seriously and recommend treatment rather than observation in most cases.

Key Characteristics

• Rough, sandpaper-like texture (often easier to feel than see)
• Pink, red, or skin-coloured
• Typically 2–10 mm in diameter
• Often multiple lesions in sun-exposed areas (“field cancerisation”)
• More common in fair-skinned individuals, those over 40, and people with significant sun exposure history

Photodynamic Therapy — The Clinical Light Treatment

This is where the confusion with red light therapy arises. Photodynamic therapy (PDT) is an established, NICE-approved treatment for actinic keratoses, and it does involve red light. But the mechanism is entirely different from photobiomodulation.

PDT for actinic keratosis works as follows:

1. Photosensitiser application — a cream containing a photosensitising agent (5-aminolaevulinic acid/ALA or methyl aminolaevulinate/MAL, branded as Metvix in the UK) is applied to the affected skin
2. Incubation period — the cream is left on for 3 hours (ALA) or 3 hours (MAL) under occlusion. During this time, the photosensitiser is selectively absorbed by the abnormal, rapidly dividing cells of the AK
3. Light activation — the treated area is exposed to red light at approximately 630–635 nm. The light activates the photosensitiser within the abnormal cells, generating reactive oxygen species (singlet oxygen) that destroy the cells from within
4. Selective cell death — because the photosensitiser concentrates preferentially in abnormal cells, the treatment selectively destroys AK cells while largely sparing normal surrounding tissue

Morton et al. (2002) published a landmark RCT in the British Journal of Dermatology showing that MAL-PDT achieved complete clearance rates of 89–91% for thin AKs, comparable to cryotherapy. Subsequent meta-analyses have confirmed PDT as a first-line treatment for multiple or field AKs.

Why Home Red Light Therapy Is Not PDT

Home red light therapy devices emit similar wavelengths to PDT lamps (630–660 nm red light). But without the photosensitising cream, the light does not generate the reactive oxygen species that destroy abnormal cells. The mechanism is completely different:

• PDT = photosensitiser + light = selective cell destruction
• PBM (red light therapy) = light alone = mitochondrial stimulation, enhanced cellular metabolism

Red light therapy without a photosensitiser will not treat actinic keratoses. There is no evidence that PBM alone clears AKs, and there is a theoretical concern that stimulating cellular metabolism in pre-malignant cells could potentially accelerate their progression — though this has not been demonstrated clinically.

The Honest Position

If you have actinic keratoses:

1. See a dermatologist. AKs are pre-cancerous lesions that require proper medical assessment and treatment
2. Do not attempt to treat AKs with home red light therapy devices. It will not work, and it could delay appropriate treatment
3. PDT is an excellent treatment option — ask your dermatologist whether it is suitable for your lesions. It is available on the NHS and through private dermatology clinics
4. If you use red light therapy for other purposes (anti-ageing, pain), there is no evidence that the low-level light from home devices worsens AKs, but you should discuss this with your dermatologist if you have lesions in the treatment area

Seborrheic Keratosis

What It Is

Seborrheic keratoses (SKs) are the most common benign skin growths in adults over 50. They are entirely unrelated to actinic keratoses despite the similar name. SKs are not caused by sun exposure, are not pre-cancerous, and do not require medical treatment unless they are symptomatic or cosmetically bothersome.

Key Characteristics

• Waxy, “stuck-on” appearance (as if the lesion could be peeled off)
• Brown, black, or tan coloured
• Range from a few millimetres to several centimetres
• Often described as having a “warty” texture
• Appear on the trunk, face, and arms
• Increase in number with age — most people over 60 have at least one

What the Evidence Shows for Red Light Therapy

There is virtually no clinical evidence examining red light therapy for seborrheic keratoses, and there is no biological rationale to suggest PBM would remove or reduce them. SKs are benign growths of keratinocytes (skin cells) with a genetic and age-related basis. They are not inflammatory, not degenerative, and not responsive to collagen-remodelling interventions.

Standard treatments for SKs that are cosmetically bothersome include:

• Cryotherapy (liquid nitrogen freezing) — the most common NHS treatment
• Curettage and electrocautery
• Laser ablation (CO2 or Er:YAG laser — these are ablative lasers, not photobiomodulation)

Bottom line: Red light therapy will not remove or meaningfully reduce seborrheic keratoses. If they bother you, see your GP or dermatologist for removal via cryotherapy or curettage.

Keratosis Pilaris (KP)

What It Is

Keratosis pilaris is an extremely common skin condition — affecting up to 40% of adults — characterised by small, rough bumps on the outer upper arms, thighs, cheeks, or buttocks. Often called “chicken skin,” KP occurs when keratin (a skin protein) plugs the hair follicle openings, creating tiny raised bumps.

Key Characteristics

• Small (1–2 mm) flesh-coloured or slightly red bumps
• Rough, sandpaper-like texture
• Most common on the outer upper arms and thighs
• Often worse in winter (dry air) and improves in summer
• Tends to improve with age
• Associated with atopic dermatitis (eczema), asthma, and dry skin
• Entirely benign — a cosmetic concern only

What the Evidence Shows for Red Light Therapy

There are no published clinical trials examining PBM for keratosis pilaris. However, there is a plausible (if limited) rationale for mild benefit:

Anti-inflammatory effects. KP bumps often have a mild inflammatory component — redness surrounding the keratinous plugs. PBM’s well-documented anti-inflammatory effects (reduction of IL-1beta, TNF-alpha) could theoretically reduce this redness.

Skin barrier function. Some preliminary research suggests PBM may support skin barrier function and hydration, which could help in a condition exacerbated by dry skin.

What PBM cannot do for KP: The fundamental problem in KP is excess keratin production that plugs follicles. PBM does not reduce keratin production. The bumps themselves will not be resolved by light therapy.

Practical Approach for KP

If you already own a red light therapy device and want to try it for KP, it is unlikely to cause harm and may modestly reduce associated redness:

• Wavelength: 630–660 nm (red) — the condition is superficial
• Dose: 4–6 J/cm² per session
• Frequency: 3–5 times per week
• Duration: 8–12 weeks before assessing
• Combine with established KP treatments for best results: urea-based moisturisers (10–20% urea), salicylic acid or lactic acid exfoliants, and avoiding harsh scrubbing

Do not purchase a red light therapy device specifically for KP. The evidence does not support the investment.

Red Light Therapy Near Skin Lesions — Safety Considerations

A common and reasonable question from people who use red light therapy for other purposes: is it safe to use red light near skin lesions?

General Principles

Benign lesions (SKs, moles, skin tags, KP): There is no evidence that PBM at standard home-device irradiances causes benign lesions to become malignant. The energy levels involved (5–50 mW/cm²) are far below those that cause DNA damage (which requires UV radiation, not visible red or NIR light). Standard PBM use around benign lesions is generally considered safe.

Pre-malignant lesions (AKs): The theoretical concern is that stimulating cellular metabolism in cells that are already on a pathway toward malignancy could accelerate that process. This concern has not been validated in clinical studies, but it has also not been ruled out. The prudent approach is to have AKs treated by a dermatologist and to discuss PBM use with them.

Known or suspected malignancies: Do not use red light therapy over areas of known or suspected skin cancer. While the evidence for PBM promoting cancer growth is weak and conflicting, the precautionary principle applies. Get a proper diagnosis and treatment first.

When to See a Dermatologist

Use the ABCDE criteria for any skin lesion you are unsure about:

• Asymmetry — one half does not match the other
• Border — irregular, ragged, or blurred edges
• Colour — uneven colour (multiple shades of brown, black, red, or blue)
• Diameter — larger than 6 mm (though melanomas can be smaller)
• Evolving — changing in size, shape, or colour over time

Any lesion meeting these criteria warrants urgent dermatological assessment regardless of whether you use red light therapy.

Summary Table

Condition	Can RLT Help?	Evidence Level	Action Required
Actinic keratosis	No — PBM alone is ineffective. PDT (which uses light + photosensitiser) is effective but is a clinical procedure	N/A (wrong mechanism)	See a dermatologist
Seborrheic keratosis	No	No evidence	Cryotherapy or curettage if cosmetically bothersome
Keratosis pilaris	Possibly mild redness reduction	Very low (theoretical)	Try topical keratolytics first; RLT is an optional adjunct

The Honest Assessment

This is a page where the most important thing to communicate is what red light therapy cannot do.

For actinic keratoses, the connection to “light therapy” is a source of genuine confusion. PDT is an effective, evidence-based treatment for AKs — but it requires a photosensitising agent and is performed in a clinical setting. Home red light therapy devices will not treat AKs, and relying on them could delay treatment of a pre-cancerous condition.

For seborrheic keratoses, there is simply no mechanism by which PBM would help. These are benign growths best managed by cryotherapy if they bother you.

For keratosis pilaris, PBM may offer marginal cosmetic benefit through inflammation reduction, but the mainstay of KP management remains moisturisation and gentle chemical exfoliation. Do not buy a device specifically for this purpose.

The responsible message: if you have any skin lesion you are uncertain about, see a dermatologist. Red light therapy is a valuable tool for many conditions, but skin lesion diagnosis and management is not one of them.

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This article is for informational purposes only and does not constitute medical advice. Actinic keratoses are pre-malignant lesions that require medical assessment. If you have rough, scaly patches on sun-exposed skin, consult a dermatologist for proper diagnosis and treatment.