Lasers in Dermatology

What is a laser?

A laser (an acronym for Light Amplification by Stimulated Emission of Radiation) is a device for producing a beam of intense light which can be controlled and precisely focussed. It works through the conversion of its light energy into heat at specific target points. The high power energy of the laser had been harnessed for use in many fields since the first working model was made by T.H. Maiman in America in 1960. Lasers have been widely used in medicine and new lasers have been developed which have extended and improved treatment possibilities.

Types of laser

Argon Laser

The Argon laser emits blue-green light at 488 nm and 514 nm. These wavelengths of light are preferentially absorbed by oxyhaemoglobin and, to a lesser extent, by melanin in the skin. The light energy absorbed by erythrocytes within blood vessels is converted to heat, leading to red cell destruction and thrombosis of small vessels.

Tunable Dye Laser 577 nm

By increasing the wavelength of light from 577 nm to 585 nm the penetration depth is increased from 0.5mm to 1.2 mm in port wine stained skin while maintaining the same degree of vascular selectivity.

Pulsed Tunable Dye Laser.

By using microsecond impulses it is possible to confine thermal injury to targetted blood vessels without heat diffusion to surrounding tissue.

Carbon Dioxide Laser

Carbon dioxide laser therapy removes tattoo pigment after vapourisation of the epidermis and superficial dermis and is used also for skin resurfacing. Although effective, this laser has a high incidence of scarring and pigmentary disturbances in inexperienced hands.

Ruby laser

Q-switching whereby high energy levels (5-10J/sqcm) are delivered in ultrashort pulse widths (10-80ns) of Ruby, Nd:YAG and Alexandrite lasers, has offered significant advances in the treatment of tattoos. Ruby lasers emit light at 694 nm. The Ruby laser can also be used to treat green tattoos.

Alexandrite Laser

The Alexandrite laser, with a wavelength of 755 nm produces slower results than the Ruby and Nd:YAG Q-switched lasers, but may be of value in the treatment of tattoo pigments of other colours.

Nd:YAG lasers

Nd :YAG lasers emit light at 1064 nm. Frequency doubling of Nd:YAG laser light produces green light of wavelength 532 nm. This green light can produce fading of red tattoo pigments.

Flash-lamp pulsed tunable dye lasers have been provided at six hospitals in the UK through the Disfigurement Guidance Centre's Laserfair Appeal, and the first of these NHS dedicated Laser Clinics became operational on 5th June 1990 at Bangour Hospital in Edinburgh. Port wine stains and other vascular lesions can be treated on the NHS at these six hospitals and, by now, at many other NHS and private hospitals throughout the UK. Your GP can refer you for treatment.

Some conditions treated by skin lasers

Vascular lesions

Cutaneous lesions with an abundance of blood vessels can be treated using these new lasers:

Pigmented lesions

Benign cutaneous pigmented lesions (hyperpigmented) such as: can be effectively removed in the absence of unneccesary loss of normal skin pigmentation at the treated sites.

Tattoos

Professional and non-professional, single or multi-coloured can be removed by the new generation of Q-switched lasers. An important issue here is that some lasers break the skin surface producing bleeding during treatment whereas others do not.

It is perhaps worth reflecting on the fact that we live and practice in a society that seeks perfection and instant gratification. Although dramatic improvement in most vascular lesions is now possible, patients (or parents) can be surprisingly disappointed with techniques that produce anything less than complete clearing, even if there are no adverse reactions. We should temper our enthusiasm with realistic treatment goals and timetables, and improve patient education. Each physician should make realistic promises to the patient based on his or her own personal experience and results.
McDaniel DH. Cutanesous Vascular Disorders: Advances in Laser Treatment. Cutis 1990 45:339-360
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