Continuing Education Activity
Intense pulsed light (IPL) therapy was first developed in 1992 to treat leg telangiectasias. Its effectiveness was initially demonstrated in studies on rabbit ear veins, showcasing its ability to thermocoagulate vessels with minimized purpura and epidermal damage. This activityprovides an in-depth review of the physics underlying IPL therapy, covering its indications, contraindications, and technical aspects of delivery. It emphasizes the pivotal role of the interprofessional healthcare team in administering IPL treatments, fostering a comprehensive understanding of this versatile technology's applications. Since the FDA's approval of the first IPL device in 1995, continuous innovation has expanded its clinical applications, making it a safe and effective option for various pigmented and vascular disorders, hair removal, and addressing signs of photoaging.
IPL devices stand out for their use of flashlamps and bandpass filters, enabling the generation of pulsed light with varying wavelengths, durations, and fluences. This versatility makes IPL an invaluable tool in dermatology, effectively treating conditions such as melasma, lentigines, telangiectasias, and rosacea. This activity underscores the significant advancements in IPL technology and its increasing affordability, highlighting its present status as a widely utilized modality in addressing both functional and cosmetic dermatological concerns.Learners will gain a comprehensive understanding of IPL therapy, empowering them to integrate this technology effectively into their clinical practice for enhanced patient outcomes.
Objectives:
Differentiate between the specific dermatologic conditions for which intensepulsedlight therapy and laser energy are optimal, considering factors such as pigmentation and vascularity.
Identifydermatologic conditions appropriate for intense pulsed light therapy, considering factors such as pigmentation and vascularity.
Implement standardized safety protocols for intensepulsedlight therapy in order to avoid post-treatment complications.
Collaborate with members of the interprofessional team to ensure a clear understanding ofintensepulsedlight therapy indications, patient concerns, and posttreatment care plans.
Introduction
Intense pulsed light (IPL) therapy was first developed in 1992 by Doctors Goldman, Fitzpatrick, and Eckhouse for the treatment of leg telangiectasias. Proof-of-concept studies were conducted on rabbit ear veins, demonstrating IPL's ability to thermocoagulate vessels while minimizing purpuraand epidermal damage.[1]Since the first United States Food and Drug Administration (FDA)-approved IPL device wasbrought to the market in 1995, thistechnology has undergonesignificant innovation and improvement in its clinical applicationsand affordability.[2][3]
IPL devices are unique in that they employ flashlamps and bandpass filters to produce pulsed light ofvarying wavelengths, durations, and fluences.Thesecharacteristicsprovide IPLversatility inaddressing numerous dermatological conditions.[4][5]IPL issafe and effective in treating benign pigmented and vascular disorders as well as performing hairremoval and reducing signs of photoaging.[6]Currently, IPL is an invaluable tool in dermatology and is frequently used to address a broad range offunctional and cosmetic concerns.[7]
Anatomy and Physiology
IPLuses aflashlamp to emit polychromatic light across a broadwavelength spectrum of approximately 400to 1400 nm, which makes it fundamentally different from a laser (light amplification by stimulated emission of radiation), whose light is necessarily monochromatic (of a single wavelength), collimated (with waves running in parallel), and coherent (with waves in phase).[6] The advantage ofbroadband light is that it allows for greaterversatility in treating a variety of skin types and conditions. Furthermore, the wavelength of light emitted from an IPL machine can be adjusted by applying filters thatprevent the delivery of light with wavelengthsshorter than the desired value (seeImage. XXX). The result is that the desired wavelength is delivered along with longer wavelength light (such as infrared), but shorter wavelength light (such as ultraviolet) does not reach the patient.
Lasers and light energy delivery devices produceaclinical effect when theirphotonsare absorbed by the skin, resulting in thedeposition ofthermal energy.[8]Chromophores (eg, hemoglobin, water, melanin) in the skin absorb the photons and are subsequently heated, causing their destruction through thermocoagulation. This phenomenon of selective photothermolysis is the underlying basis of IPL technology.[9]
Indications
The FDA has approved IPL therapy for:
Telangiectasias
Photorejuvenation
Facial wrinkles
Hyperpigmentation
Lentigines
Ephelides
Melasma
Rosacea
Acne vulgaris
Poikiloderma of Civatte
Port-wine stains
Hemangiomas
Legveins
Venous malformations
Removal of unwanted hair[10]
IPL was also recently introduced to ophthalmology to manage dry eye disease due to meibomian gland dysfunction.[11]
Contraindications
IPLtreatment sessions aregenerally safe and tolerable. However, it may be beneficial toavoid IPL in certain individuals, such as those with a recent sunburn andin pregnant or breastfeeding women. IPL has also been found to induce herpes simplex virus (HSV) outbreaks, similar to laser treatments, via transient hyperthermia and reactivation of latent HSV in the trigeminal ganglion.[12] In patients with a previous history of HSV infection, starting prophylactic antiviral therapy (oral acyclovir, valacyclovir, or famciclovir) may be warranted a day before IPL treatment and continue for up to2 weeks afterward.[13][14]
Equipment
The underlying mechanism of IPL therapy involves4 crucialconcepts: wavelength, pulse duration, fluence,and spot size.
Wavelength
Flashlamps emit polychromatic light within a wavelength spectrum of approximately 400to 1400 nm.[15] The wavelength of light that reaches the patient can beadjustedusing cut-off filters, which allow certaintissues to be targeted via selective photothermolysis. The skin contains different chromophores(molecules that absorb light of a specific wavelength), thereby converting it to thermal energy.Whenselecting a wavelength, the healthcare provider should be aware of competing chromophores within the treatment area. For example, melanin in the epidermismay shield the targetedchromophoreslocated in a deeper layer of the skin.
This concept is particularly important when administering IPL in patients with darker skin types, as special attention must be given to treating them safely and preventing dyschromia. Since melanin tends to absorb light atshorter wavelengths, selecting longerwavelengths that penetrate deeper and spare the epidermis may benefit patients with darker skin. Given this same principle, shorter wavelengths effectively treat pigmented lesions in patients withlighter skin.[16]
Pulse Duration
Selection of the pulse duration is based on the thermal relaxation time (TRT) of the chromophore, or the timerequired for the temperature in the heated tissue to decrease to 37%of its peak.[17]To minimizethermal damage to the target tissue, the pulse duration (ie, the length of time the energy is being delivered) should be shorter than the target tissue's TRT.If the target is reheatedbefore the TRT has elapsed after the last pulse of light is delivered, thesurrounding tissue maysuffer subsequent scarring or hypopigmentation.
Some IPL devicescan only producea single pulse,whereas others can produce multiple sequential pulses. Delay times between sequential pulses are routinely10to 12 ms to accommodate epidermal TRT, whereas a 20-to-40 ms TRT is advisedfor patients with darker skin types.Thermal relaxation time is also adjusted to account for chromophore and lesion size. Larger chromophores, such as hair follicles, require more time to cool down due to their longer TRT. Allowing appropriateTRT between pulsesminimizes the risk of complications bypreventing epidermal temperatures from rising above 70 ºC.
Fluence
Fluence, or energy density, describes the amount of energy delivered per unit area. IPLcan deliver afluence of up to 40 J/cm^2,whereaspigmented lesionsare usuallytreated with a fluenceof only 16to 20 J/cm^2. A higher fluence may be used if a target is located deep within the skin or the chromophoresareinefficient at absorbing light. Importantly, side effectstend to occur more frequently at higher fluences and in darker-skinnedindividuals.[18] Cooling devices assist with the delivery of higher fluences while protecting the epidermis from damage (epidermal bypass), as the thermal energy is delivered todeeper tissue.[19]
Cooling systems
Cooling systemsprovide epidermal protection and permit greater fluences to reach deeper targets. Cooling systems can be internal, such as integrated chilled tips, pulsed cryogen sprays, or cooled glass chambers. External cooling methods include ice packs, forced-air cooling,or cold ultrasound gel applied to the skin before a treatment session. The cold gel reduces the friction of the handpieceon the skin, diffuses the surface heat releasedfrom the handpiece, anddecreases the refractive index between air and skin,allowing for better penetration and light absorption.
Spot Size
Spot size is the diameter of light that is emitted from the flashlamp. Increased spot size allows for light to penetrate deeper because scattering isminimized. Thus, a smaller spot size will require higher fluences to target deeper dermal targets effectively. Spot size is controlledusing interchangeable aperture pieces (seeImage.XXX).
Personnel
IPLght treatments, like many laser treatments, are typically provided in the outpatient clinic setting. A physician or surgeon may perform them, but it is frequently a midlevel healthcare provider, such as a physician assistant or a nurse practitioner, providing the treatments. In some regions, registered nurses are permitted to provide laser and IPL treatments as well. Regardless, having a physician, such as a plastic surgeon or dermatologist, involved in the care team ensures that an experienced clinician can manage complications promptly should they arise.
Preparation
Preparation for IPL treatment requires finding the patient a comfortable, private treatment room to expose whatever skin area is problematic without fear of embarrassment. The IPL machine requires a few square feet of floor space and frequently a 220-V outlet for power, which is not uniformly available in the United States. A cold gel is also helpfulfor improving patient comfort as well as energy transmission from the handpiece to the skin.
IPL can damage pigmented ocular tissues such as the retina; therefore, eye protection with the appropriate optical density is critical for the patient and the IPL treatment provider. Eye shields should not berepositioned midprocedure, as this may interfere with the treatment session and lead to inadvertent ocular damage.
Preprocedure informed consent is important for IPL treatments, as it is for any procedure, and the discussion should focus on the development of reasonable expectations, particularly with respect to final outcome, anticipated number of treatments required to achieve the desired result, postprocedure precautions, like avoiding sun exposure, and the potential for complications, such as temporary or permanent hyper or hypopigmentation, erythema, crusting, blistering, and scarring.[20][21]
Technique or Treatment
In contrast to lasers, IPL devices produce noncoherent, polychromatic light with a broadrange of wavelengths. Their fluence, pulse duration, spot size, and filterwavelength can be adjustedin order to target specific chromophores. Thus, IPL devices can treat a wide variety of lesions and skin types. Lesion clearance oftendepends on the frequency of treatment sessionsbecause the effect of pulsed light is cumulative, routinely requiring 3to 6 treatments every2to 4 weeks for the full clinical effect to be achieved.[4]
Lesions that are more heavily pigmented may require a higher number of treatment sessions.Lesions deeper within the dermis may also requiremore treatments asthey are more challenging to reach. Comparedwith laser devices, IPL is associated with a shorter recovery time and lower equipment costs. Disadvantages of IPL include incorporating the lampand cooling device into the handpiece, which contributes to device heaviness (seeImage.XXX). Cold gel applied to the skinalso diminishesthe visibility of immediate local skin reactions.[6]
Selection of the appropriate filter is critical to achieving the desired results, just as setting appropriate fluence and pulse duration is essential for avoiding complications. The default settings on most IPL devices are designed to provide safe treatments with minimal risk of complications, but using thesecautious settings may prove less clinicallyeffective than more aggressive energy delivery parameters (seeImage.XXX). Starting a course of treatment with conservative settings, however, is advisable. Shorterwavelength filters permit less skin penetration than longer wavelength filters. Typical filter wavelengths and their indications are listed in the table below:
Table
IPLFilter Settings Indication
Complications
Although side effects of IPL are typicallyrare and minimal in severity, the most common adverse events include pain and erythema.Other reported side effects includeedema, bullae, hematoma, crusting, hyper- or hypopigmentation, leukotrichia, scarring, keloid formation, and infection.[21]For untrained medical providers, theuse of inappropriatedevicesettings and administration of excess energycanlead to nonspecific thermal damage and complications. IPLisparticularly challenging to use on dark-skinned individuals, and careful consideration must be given to these patients.
Shorter wavelengths are generally reserved for fair skin types, as these wavelengthsare absorbed bymelanin and lead to pigmentation changes in patients with darker skin. However, device-related cooling technology has helped minimize these side effectsin patients with darker complexions. Skin reactions typically last for about 2to 48 hours after treatment and often depend on the fluence, pulse duration, and specific treatment area. Higher fluences and pulse durations, thinner skin, and darker skin types may increase the likelihood of adverse events.
In patients undergoing hair removal,the adverse effect of paradoxical hypertrichosis may occur.[22] This is the phenomenon of the growth of fine, dark hair in areas close to the target tissue, especially in patients with darker skin types (Fitzpatrick III-VI). The underlying mechanism has not been fully elucidated. Still, potential causes include IPL stimulating hair follicular stem cells to promote hair growth and inducing the release of cytokines and growth factors with the conversion of vellus hairs to terminal hairs.[23][24]Treatment options include increasing the energy, decreasing the interval between treatments, using more cooling, changing the wavelengths (eg, from IPL to 1,064-nm Nd:YAG laser), and using topical eflornithine to slow down hair regrowth after treatments.
Clinical Significance
IPLutilizes high-intensity light sources to treat a wide range of dermatological conditions. IPL technology has evolved tremendously since the 1990s with theaddition of higher-intensityflashlamps,cut-off filters, and cooling systems. These features haveenabledIPL to be an ideal tool fortreating a variety of pigmented lesions, including solar lentigines and ephelides, vascularlesions such as telangiectasias, port-wine stains, hemangiomas, and leg veins, as well as unwanted hair andphotoaging.[25][26] Newer IPL devices also allow for more specific targeting with increasedaccuracy and less light scattering.
Enhancing Healthcare Team Outcomes
Achieving the best outcomes with intense pulsed light therapy involves an interprofessional team ofhealthcareproviders, including a skilled dermatologist or plastic surgeon and often a physicianassistant or nurse practitioner, aesthetician, medical assistant, and office staff. The patient should beeducated on what to expect during and after the procedureas well as potential side effects. For example, thepatient should be counseled on cold gel application before IPLdelivery and usingprotective eyewear during sessions as well as the importance of sun protection after treatment. It is also important to gauge the patient's expectations andassess clinical improvement accordingly. Patients should be informed that thebest results are achieved after a series of at least2 or more IPL treatments.
Figure
Commonly used filters for an intense pulsed light delivery system. These prevent the transmission of light with wavelengths shorter than the number marked on the filter. Contributed by Marc H Hohman, MD, FACS
Figure
Interchangeable apertures permit selection of appropriate spot size for intense pulsed light delivery. Contributed by Marc H Hohman, MD, FACS
Figure
Handpiece used for intense pulsed light delivery, with filter inserted and aperture attached. Contributed by Marc H Hohman, MD, FACS
Figure
Touchscreen interface for intense pulsed light delivery system that permits adjustment of fluence, pulse width, pulse frequency, and cooling. Contributed by Marc H Hohman, MD, FACS
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Disclosure: Anita Gade declares no relevant financial relationships with ineligible companies.
Disclosure: Gabriella Vasile declares no relevant financial relationships with ineligible companies.
Disclosure: Marc Hohman declares no relevant financial relationships with ineligible companies.
Disclosure: Richard Rubenstein declares no relevant financial relationships with ineligible companies.
