Introduction 

Skin conditions such as acne vulgaris, vascular malformations, and pigmentary disorders are common reasons for seeking medical care and can occur across a wide age range. 

Acne vulgaris alone is estimated to affect approximately nine percent of people worldwide. In the Western world, acne is seen in up to 95% of adolescents, with 20-35% experiencing moderate to severe acne. Acne and other skin conditions can lead to physical symptoms such as scarring and post-inflammatory hyperpigmentation or depigmentation. They can also cause significant psychological distress, including low self-esteem and depression.

These conditions are usually managed by healthcare professionals using various topical and oral medications, which can include retinoids, antibiotics and hormonal contraception. Treatment choice often depends on the patient’s preferences, the type of condition, severity and response to previous treatments.¹ When these standard treatments are ineffective or poorly tolerated, energy-based therapies such as light devices and lasers may be considered as adjunct options.  

Lasers are an innovative clinical tool first used for dermatological conditions around four decades ago.² Since then, the design and application of laser technology has been extensively researched and evolved considerably, resulting in a wide range of laser devices available for medical use. 

The British Association of Dermatology (BAD) recognises several skin conditions for which laser treatment may be beneficial, including seborrhoeic keratosis, actinic keratosis, and vascular birthmarks. However, these treatments are generally limited to specialist or private healthcare settings. For acne, the BAD emphasises that the evidence for laser treatment in active acne remains limited, with variable results. 

Continue reading to explore laser therapy, including its components, types of lasers, benefits, risks and limitations.

Principles of Laser Therapy 

What is Light?

We are constantly surrounded by invisible electric and magnetic fields around us, some from natural sources like the sun, and others generated by human activity. Together, these fields form the electromagnetic field, which is consists of waves. As these waves travel, they form electromagnetic radiation (EMR).  

The EMR spectrum contains a wide range of wavelengths, but only a small portion is visible to the human eye. This is known as visible light. 

Light is a part of the electromagnetic radiation spectrum. Each colour that we can see in day-to-day life has a different wavelength. For example, red has a longer wavelength than blue; our eyes detect these wavelengths and interpret them as different colours. A combination of various wavelengths of light creates white light. This light can originate from a natural source, like the sun, or an artificial source, like a torch. 

What is a laser?

The term “laser” stands for Light Amplification by Stimulated Emission of Radiation.

As mentioned earlier, natural light is made of different colours and travels in many directions. However, a laser produces light in a specific and controlled way by: 

• Exciting many atoms or molecules so they can store energy 
• A tiny packet of light called a photon is then released to hit one of those atoms, releasing another photon that is identical in colour, direction, and timing 
• This is called stimulated emission, which leads to lots of identical photons moving together in sync
• Mirrors or optical structures within the laser device help reflect (bounce) the light back and forth 
• This creates a beam of artificial light that is monochromatic (single wavelength) and straight

This makes lasers extremely precise and effective for medical applications, especially in dermatology, which is the branch of medicine focusing on the skin, hair, nails and mucous membranes.³

Types of Lasers and Their Applications 

Ablative vs Non-ablative Lasers 

In dermatology, lasers are broadly categorised as ablative or non-ablative types.. 

Ablative lasers work by removing the outer layers of the skin, stimulating a more intensive healing process. The aim is to strongly boost collagen production, a protein that helps the skin stay smooth and firm. By removing the outer layers of the skin, they can also be used to remove benign (non-cancerous) skin growths such as seborrheic keratosis. However, ablative treatments generally require a longer healing time and carry a higher risk of complications. Common examples include CO₂ lasers and Er: YAG lasers. 

Non-ablative lasers, on the other hand, target the middle layers of the skin without damaging the surface. This stimulates collagen production while leaving the surface layers of the skin intact, resulting in faster recovery times. One example of a non-ablative laser is the pulse dye lasers (PDL). 

Subtypes of Lasers 

Within the broad categories of ablative and non-ablative lasers, devices are further classified based on which part of the skin they target — known as the chromophore, or the specific structure in the skin that absorbs the laser’s energy.

Common subtypes include fractional, vascular, and excimer lasers.

Fractional lasers and their benefits 

Fractional lasers bridge the gap between ablative and non-ablative techniques. They work on the outer surface and the middle layers of the skin simultaneously. These lasers treat small columns of skin tissue, leaving surrounding areas untouched. They primarily target the water molecules in the skin tissue. This method allows for faster healing and results in fewer side effects.⁴ 

Examples include:

• Fractional CO₂ laser

Example conditions treated:

• Acne Scarring

Vascular lasers 

Vascular lasers specifically target blood vessels in the skin by focusing on the red pigment within them, called oxyhaemoglobin. They are used to treat redness, broken blood vessels, and vascular birthmarks such as port-wine stains. 

Examples include:

• Pulse dye laser (PDL)
• Long-pulsed Nd:YAG laser
• KTP laser 
• Dye laser
• Argon laser 
• Ruby laser 

Example conditions treated:

• Port-wine stains 
• Spider angioma 

Excimer lasers 

Excimer lasers are a special type of gas-based laser that emits UVB light. Unlike other laser types, which work primarily through heat, excimer lasers work via immune modulation and repigmentation.

Examples include:

• 308 nm XeCI excimer laser 

Example conditions treated:

• Vitiligo
• Psoriasis 
• Alopecia Areata⁵

Benefits of Laser Therapy

Laser therapy offers several key advantages:

• Lasers allow for precise, targeted treatment, meaning the specific molecules in the skin can be selectively targeted. These include: 
  • Melanin - the pigment that gives skin its colour and protects it from UV light
  • Haemoglobin - absorbs light and contributes to the pink or  red appearance of the skin
  • Water - absorbs light
• One review discusses how laser therapy allows  ‘multi-dimensional skin improvements’, meaning it can enhance multiple aspects of skin health:
  • Active acne – by reducing sebaceous gland activity and Cutibacterium acnes (formerly known as P. acnes) bacteria
  • Scarring – through collagen remodelling and resurfacing 
  • Erythema and pigmentation – via selective photothermolysis of blood vessels and pigment cells

This suggests that laser treatments can simultaneously improve skin texture, tone, and inflammation by acting on various mechanisms within the skin.

• Some studies also suggest patients report increased satisfaction and confidence after treatments. Therefore, lasers can have important psychological and social benefits, beyond their physical benefits.⁶

Risks and Limitations

Risks 

The main risks associated with laser therapy involve potential harm to the eyes or the skin.

Risks to the eyes include:

• Corneal burns 
• Keratojunctivitis 
• Cataracts

Risks to the skin include: 

• Hyperpigmentation 
• Hypopigmentation
• Scarring 
• Scabs 
• Blistering 

The overall level of risk depends on several factors, such as skin type, laser type, and the expertise of the practitioner. Suitable protective measures and professional supervision should be undertaken to minimise such risks.

Limitations

Laser therapy also has several limitations. These include high treatment costs, limited access to laser therapy clinics, and the requirement for multiple sessions. Results can also vary between individuals, as the effectiveness of treatment depends on skin type, condition severity, and healthcare professional expertise.⁷

Additionally, many studies on laser therapy are small-scale and short-term, making it difficult to determine how long the benefits really last. There is also limited evidence comparing the cost-effectiveness of laser treatments to more conventional therapies, such as topical or oral medications.

According to the National Institute for Health and Care Excellence (NICE) and the BAD, laser treatments can be useful for certain patients. However, procedures should only be performed by trained specialists. NICE also highlights the need for more long-term and independent studies to fully understand the risks, benefits, and costs of laser use in dermatology. Due to limited research evidence and mixed outcomes, laser therapy is not currently recommended for the management of acne vulgaris. 

Summary 

In summary, laser therapy offers a targeted and non-invasive approach to managing numerous skin conditions, including vascular lesions, scarring, and seborrhoeic keratosis. Lasers operate on the principles of light to create specific light wavelengths to produce a powerful beam of light that can penetrate or heat the skin to stimulate healing and collagen production. 

Broadly, lasers are classified as ablative or non-ablative, depending on whether they remove the skin’s surface layers or work on deeper layers. The NICE and the BAD recognise the effectiveness of lasers in certain conditions, such as vascular malformations, benign growths and pigmentary disorders. However, they also highlight that results can vary; thus, treatment should only be recommended and performed by trained healthcare professionals, typically as adjunct therapies after standard first-line treatments. 

Beyond their cosmetic benefits, laser therapies can provide psychosocial advantages, such as improved confidence and quality of life, by enhancing skin texture and appearance. Nevertheless, it is important to highlight that laser therapies are not without risk, and further high-quality research is needed to establish their long-term safety and effectiveness. 

Overall, while lasers are not considered a first-line treatment, they may serve as a valuable adjunct for selected patients.