Lasers for skin: which laser does what

Key takeaways

• Lasers work by matching a wavelength to a target: melanin (pigment and hair), haemoglobin (redness and vessels), water (resurfacing and scars) or ink (tattoos).
• Broadly, there are lasers for hair, for pigment, for redness, and resurfacing lasers for scars, texture and fine lines.
• Ablative lasers (CO2, erbium) remove thin layers of skin and need more downtime. Non-ablative and fractional approaches heat the skin with less downtime but need more sessions.
• Brown skin needs extra caution, because laser can cause darkening or lightening that may last a long time, especially with stronger resurfacing settings.
• Ask what the laser is targeting in your skin, how many sessions, what downtime, and what the plan is if your skin darkens.

How does a laser know what to treat?

See, what happens is, laser light is one pure wavelength. Different things in the skin absorb different wavelengths. Melanin in pigment and hair roots absorbs some. Haemoglobin in blood vessels absorbs others. Water, which is in every skin cell, absorbs the far infrared. Tattoo ink absorbs depending on its colour. The skill is in choosing the wavelength, the pulse length and the energy so the target heats up and the surrounding skin stays safe.

That is very important to understand in Indian skin. Our skin has more melanin in the surface layer. A laser aimed at a pigment spot or a hair root also "sees" the brown skin around it. If the settings are wrong, the surface skin gets heated too, and the result can be a burn, a dark patch or a pale patch.

Which laser does what?

This table is simplified from DermNet's overview of lasers in dermatology. The wavelengths are given in nanometres (nm).

In Indian skin, the longer wavelengths such as 1064 nm are often chosen because they pass the surface melanin more safely. The trade-off is that they can be less punchy on fine targets, so more sessions may be needed.

What is the difference between ablative, non-ablative and fractional?

• Ablative lasers, such as CO2 and erbium, vaporise very thin layers of skin. The skin then heals with new collagen. DermNet describes pulsed CO2 as a long-standing standard for facial resurfacing, with erbium giving similar results. Healing takes time, and redness can last for weeks.
• Non-ablative lasers heat the deeper skin without breaking the surface. Downtime is less, but you need a series of sessions for a smaller change each time.
• Fractional lasers, ablative or not, treat the skin in tiny columns with untouched skin between them. The untouched skin helps healing, so downtime is shorter than full resurfacing.

For brown skin, I lean towards fractional and gentler settings, spaced well apart, even if it means more sessions. DermNet says extreme caution is needed with ablative lasers in skin of colour because long-term pigment loss or patchy pigment can occur. I would rather go slowly than deal with that.

Can a laser treat melasma or tan?

Patients often ask for "a laser for my pigmentation". Normally, my first question is: which pigmentation? A freckle or a single sun spot can respond well to a pigment laser. A tattoo needs several sessions. Melasma is different. It is driven by hormones, heat and light, and aggressive laser can make it worse or bring it back darker. DermNet notes that treatment of pigmented lesions is unpredictable and that treated lesions may recur.

So for melasma I start with sunscreen and creams, and use low-energy laser or peels only as a support, not the main plan. I have explained this in treating melasma safely in Indian skin. Tan is usually best handled with sun protection and time, with a peel if needed, before thinking of laser.

What are the risks of laser on Indian skin?

DermNet lists the general side effects of laser: temporary pain, redness, bruising, blistering and crusting; infection, including cold sores flaring up; pigment changes that may be permanent in some cases; and scarring. In skin of colour, pigment change is the one I watch most closely.

You can reduce the risk on your side too: - Do not come for laser with a fresh tan. A beach weekend or a long Mumbai summer on a two-wheeler counts. - Tell me about medicines, especially acne tablets, antibiotics and anything that makes you sun-sensitive. - Tell me if you get cold sores. Some resurfacing treatments need a preventive medicine. - Stop strong acids and retinoids on the area for a few days before, unless I say otherwise. - After treatment, use sunscreen every day and avoid scrubbing or picking.

What should I ask before any laser?

Basically, five questions: 1. What exactly is the laser targeting in my skin? 2. Why this laser and not another for my skin type? 3. How many sessions, how far apart, and what is the total cost in writing? 4. What downtime should I plan for at work? 5. If my skin darkens or reacts, what is the plan?

A good answer to the last question tells you a lot about the clinic. There is more on this in questions to ask before any skin treatment.

Where do lasers fit with peels and creams?

Lasers are tools, not a plan. For acne marks I usually start with creams and sunscreen. For acne scars, a resurfacing laser is often part of a combined plan with other treatments, which I compare in acne scar treatments compared. For hair, laser is the main tool. For melasma, it is a minor helper. Chess taught me to think from the end: I decide what result we want in six months, then pick the tool that gets there with the least risk to your skin.

How we approach this at Dr Tvacha

I have used lasers since early in my practice, because I have always loved technology, and laser therapy and laser hair reduction are part of our skin services. At a Rs 499 skin consultation I tell you what is causing the problem first, and only then whether a laser suits it. You get the laser, number of sessions and fee in writing before you pay. The plan follows Diagnose, Treat, Protect, Maintain, as set out on the Second Layer Skin Plan page. For laser options for fine lines and texture, see our anti-ageing plan.

Written by

Dr Amit KarkhanisAesthetic Physician · MBBS, Dip. Dermatology (UK) · Reg. No. 2001/02/1124

Founder of Dr Tvacha, practising in Thane since 2005. Leads the weight loss and hair programmes.