The use of lasers in dermatology

Vascular lasers and IPLS: guidelines for care from the European Society for Laser Dermatology (ESLD)

Dermatology and dermatologic surgery have rapidly evolved during the last two decades thanks to the numerous technological and scientific acquisitions focused on improved precision in the diagnosis and treatment of skin alterations. Given the proliferation of new devices for the treatment of vascular lesions, we have considerably changed our treatment approach. Lasers and non-coherent intense pulse light sources (IPLS) are based on the principle of selective photothermolysis and can be used for the treatment of many vascular skin lesions. A variety of lasers has recently been developed for the treatment of congenital and acquired vascular lesions which incorporate these concepts into their design. The list is a long one and includes pulsed dye (FPDL, APDL) lasers (577 nm, 585 nm and 595 nm), KTP lasers (532 nm), long pulsed alexandrite lasers (755 nm), pulsed diode lasers (in the range of 800 to 900 nm), long pulsed 1064 Nd:YAG lasers and intense pulsed light sources (IPLS, also called flash-lights or pulsed light sources). Several vascular lasers (such as argon, tunable dye, copper vapour, krypton lasers) which were used in the past are no longer useful as they pose a higher risk of complications such as dyschromia (hypopigmentation or hyperpigmentation) and scarring. By properly selecting the wavelength which is maximally absorbed by the target--also called the chromophore (haemoglobin in the red blood cells within the vessels)--and a corresponding pulse duration which is shorter than the thermal relaxation time of that target, the target can be preferentially injured without transferring significant amounts of energy to surrounding tissues (epidermis and surrounding dermal tissue). Larger structures require more time for sufficient heat absorption. Therefore, a longer laser-pulse duration has to be used. In addition, more deeply situated vessels require the use of longer laser wavelengths (in the infrared range) which can penetrate deeper into the skin. Although laser and light sources are very popular due to their non-invading nature, caution should be considered by practitioners and patients to avoid permanent side effects. These guidelines focus on patient selection and treatment protocol in order to provide safe and effective treatment. Physicians should always make the indication for the treatment and are responsible for setting the machine for each individual patient and each individual treatment. The type of laser or IPLS and their specific parameters must be adapted to the indication (such as the vessel's characteristics, e.g. diameter, colour and depth, the Fitzpatrick skin type). Treatments should start on a test patch and a treatment grid can improve accuracy. Cooling as well as a reduction of the fluence will prevent adverse effects such as pigment alteration and scar formation. A different number of repeated treatments should be done to achieve complete results of different vascular conditions. Sunscreen use before and after treatment will produce and maintain untanned skin. Individuals with dark skin, and especially tanned patients, are at higher risk for pigmentary changes and scars after the laser or IPLS treatment.

The Relationship Between Location, Color, and Vessel Structure Within Capillary Vascular Malformations

The treatment of capillary vascular malformations by laser is well established. Despite this, only a minority of patients obtain full clearance of their lesion after treatment. Both anatomic location and color have been proposed as prognostic factors determining the amount of improvement seen after laser treatment. This study uses the technique of depth measuring video microscopy to examine the hypothesis that smaller and more deeply placed capillaries may be responsible for the poorer response seen in certain anatomic locations. Fifty sites on 44 previously untreated patients were examined resting in a temperature-controlled room at 28 degrees C. No statistically significant correlation was found between color, based on a Munsell color chart recording and capillary depth or diameter. Also, no correlation was found between diameter, depth, or type of capillary ectasia and anatomic site. The authors believe that other factors, such as alteration in blood flow between different anatomic regions, and not vessel morphology alone, may be responsible for this variation in response.