Blistering and hyperpigmentation are a transient and temporary reaction to incorrect treatment. Blistering requires that the skin be kept clean and hydrated during the five to10 days of healing. Hyperpigmentation resolves in most cases within a few months. Whereas, hypopigmentation and scarring (now very uncommon) are often the result of a complication not correctly cared for during the post-procedure healing process. All complications are the result of unwanted heating of tissue during a light-based procedure which uses controlled heat through light to elicit wanted changes in skin. The uncontrolled heat is the hidden, and sometimes ignored, second edge to the double-edged sword of lasers and pulsed light devices (often known simply as intense pulsed light). Not just the right amount of energy, but also the right exposure time can control a successful outcome and reduce complication. Many get into trouble by simply using more energy when an endpoint or outcome is not seen. The best, safest outcome is the right combination of the right temperature and the right time with the right protective cooling for the surrounding tissues. Some sources have determined that pulsed light devices are capable of creating complications with a higher frequency if compared to lasers. As we examine that, and other claims, we must be reminded that it is not the device but the user who creates the complication. Here ignorance cannot be the excuse. These complications are the compelling motivation for demands for regulation of aesthetic devices and those who use them all across the nation. Repeatedly those who look at complications and drive regulation find that measured and quantified education of the user is the single greatest tool to reducing unwanted events.

Skin Anatomy
Skin is basically divided into the epidermis, the dermis, and the subcutaneous or hypodermis. The epidermis in most people is only about 100 microns thick, the thickness of a common sheet of paper. This body wrapper can vary slightly by age and skin health but is fairly uniform on any site on the body. The dermis is the living portion of the skin and can vary dramatically by body location, age and sex of the client. Men and darker skin types tend to have a thicker dermis and more sweat glands. Nevertheless, the point must be made that in Fitzpatrick skin typing the dermis and the epidermis are not the determining factor. The determining factor is commonly the epidermal/dermal junction (E/D junction) where many things can and do occur. The E/D junction is where ethnic color originates, where tanning originates, where blistering, hyperpigmentation, hypopigmentation and scarring initiate. It is also the location of most of the superficial nerves, an indication of how important and fragile this area can be and how closely the body monitors it. The E/D junction is a key tool in developing client selection and safety. In fact, many say the correct evaluation of a client has only two basic steps. What are the correct settings for the skin target and how is it adjusted or limited by the reaction of the E/D junction? Safe application often includes cooling or protection of the E/D junction before, during and after the light pulse. Cooling should not be used just for anesthesia, but more over for the ability to offset heating by light both entering during and exiting after the light pulse(s). In fact, cooling can prevent heating and complication of nontarget areas of the skin like the E/D junction and as deep as a few millimeters of the mid-dermis.

Patient Selection
While many agree that Fitzpatrick skin typing is either inadequate or incorrectly applied, it is still the most common way to determine client qualification or exclusion in light-based procedures. As a result, there needs to be a full understanding of its genesis and progenitors. Dr. Thomas Fitzpatrick, dermatologist and medical program chairman for many years, began the work of his 1978 published scale back in the 1950s. While living abroad, he became concerned about those getting sunburned and how to both identify and protect them. Much of the SPF sun protection work we now have began with his study in the 1950s. Consequently, the process of looking at eye, hair and skin color as a determination of sun exposure risk is commonly understood. But the six skin types of the Fitzpatrick chart have a deeper and much older history that most do not know. In the early 1900s, an anthropologist of note, Dr. Felix Van Luschan, developed a measurement system for determining ethnic history or a person’s genetic line. In short, where did your ancestors come from and what impact does it have on you? Luschan developed a series of 36 colored glass slides (in shades of brown from light to dark) that were compared in color tone to one’s skin in an untanned area. After some time, Luschan refined the process down to six major skin types without the required need of comparative slides. Fitzpatrick some half-century later adopted the same six skin types. Therefore a missing link in many evaluation processes of client risk to injury is family heritage, or more simply, differences. Does the client have different hair, skin or eye color than their family in the past three generations? Is there a hidden legacy for you to be more reactive then you appear? Additionally, it is important to remember that the Fitzpatrick risk is not only on skin, hair and eye color but also the ability to tan. By example, many Asian skin types look to fall in the Fitzpatrick III range when unexposed to sun while in fact they will react as Fitzpatrick V through VI clients when regularly exposed to sun, or briefly exposed to light-based treatment. In the final analysis, it is not the tone of skin but the ability to tan or adversely react to light that is the factor to watch in evaluation. And lastly, we Americans confuse the determination even more because we are oftentimes a mix of ethnic types. How will an Asian/Celtic (Irish/Scottish) mix, by example, react to light and what Fitzpatrick type are they?

Level of Sun Exposure
Once the Fitzpatrick type has been determined, the next step is acutely dynamic. Many simply say clients tanned at the treatment site should not be treated, or at least avoided, for a period of one month post exposure on average. Not a bad rule, but let us look deeper at that statement. When skin is exposed to sun, the melanocytes at the E/D junction (about two sheets of paper or 200+ microns deep of the skin) react. Their function is to protect the surrounding cells by combining dihydroxyphenylalanine (DOPA) and tyrosine to produce a tanned umbrella covering the exposed side of the adjacent cells. These tanned cells will progress through the epidermis and slough naturally, as will all epidermal cells, in about one month. This darkened barrier to light transmission does create and issue of overheating and a complication when compared to similar untanned skin. But there is a very dynamic component to the process that is just as important. When was the skin last exposed to sun in a level of time or intensity triggering melanocyte activity? A tan is evidence of previous, and possibly repeated, sun exposure. But the skin is most reactive during the actual tanning process. Light-based treatment post recent sun exposure, or vice versa, can drive the active melanocyte to even higher levels of reaction and therefore elevate the propensity to hyperpigment. An evaluation question used by many is, “When were you last in the sun for more than 30 minutes without protection, or more than an hour with protection?” Again, the question is pointed to the treatment site, so an afternoon at the soccer fields may not preclude a bikini or arm pit treatment if it has been covered during the exposure time. During 14 to 28 days after sun exposure and 14 to 28 days after treatment, the client has a higher risk of blistering and hyperpigmentation. In some areas this may restrict when, during the calendar year, some procedures may be safely performed. It is known by experience in the Sun Belt of the United States that an existing tan is a lower risk than recent sun exposure. In fact, some experienced users exclude tan as a risk and only look to recent sun exposure as a limiting or contraindicating factor. Always be cautious of both and the risk of complication from tan or sun exposure can be managed. Know the published experience of the device you are using and honestly evaluate the user skill level. Pulsed Light devices (IPLs) have a higher known risk with tan and sun exposure than lasers. Lastly, the most common miscalculation of skin reaction or limitation due to sun exposure comes from poor user evaluation or misrepresentation by the client. Therefore, clients need to be very aware that the desire for treatment today cannot reduce or eliminate the need for safety from tan and sun exposure. During initial consultation, they should be shown what complications can happen if they misrepresent their sun exposure. To reduce tanned or ethnically colored skin’s ability to react to light, some consider use of hydroquinone, kojic acid or other tyrosine inhibitor prior to treatment. These are not bleaching agents for post-procedure application, but pre-treatment solutions that temporarily reduce or restrict tyrosine production thereby possibly reducing pigment production from light-based stimulation. (Refer to literature and manufacturer for correct use.) When treating clients with procedures, like the well-known “photofacial,” it is also preemptive to look at the treatment areas under an ultraviolet Wood’s lamp. These treatments not only react to unwanted reds and browns but also to sun damaged skin. The level of invisible sun damage can be seen as nonflorescence under the Wood’s lamp. Such an indication shows a more remarkable and perhaps complicated outcome at what would normally appear to be a safe setting. It is also important to note that between hyperpigmentation and hypopigmentation there is a zone of trauma that will create immediate oozing and possible scabbing. On darker skins types (IV to VI), the resolution of the scab at about 10 days may expose pink, unpigmented skin. Under normal sun protected conditions, the site will normally repigment quickly. This is known as transient depigmentation and it is commonly accepted that the appearance of pink skin beneath the wound is a good sign for recovery. A white appearance may be the indication of permanent hypopigmentation and often no possibility of resolution.

Lasers Versus IPL
Both pieces of equipment can do many similar things. Some procedures are better, more safely performed, with a laser. Some procedures are better performed with IPL. A laser commonly has a single monochromatic wavelength that will selectively locate a specific skin target by size, type and color intensity. IPLs produce a band of light, often involving both visible and invisible light in the Infrared A, or near Infrared, to look within a level of skin for unwanted targets. In a simple analogy, the laser knows to select the location, address of a target – avoiding all else. Whereas, the IPL knows the neighborhood of a target and tries to bias energy away from the unwanted targets and into the selected target while working to circumvent any undesired targets above it in the skin structure. With that analogy, it is easy to understand that more caution should be applied with IPL use than laser due to the fact that lasers usually have a better ability to avoid the nontarget.

Patient History and Consultation
The best way to preempt complications is by gathering a thorough patient history and conducting an in-depth consultation. In a client consultation, the goals, realities and limitations of treatment should be discussed. In the era of the Internet, many clients have researched before their visit. However, much of that information is unfiltered and unverified – and some of the information is just wrong. First, make sure the expectation of the client (outcome, numbers of treatments and cost) and the possibilities of the procedure match in both ability and outcome. There are no absolutes – like total hair removal. Second, affirm that the client is aware that treatments may be recommended, but not cures. Remind them that aesthetics, even those including light, often fall in a continuum of repair or improvement of the unwanted blemish. Furthermore, there are things that induce the unwanted target like lifestyle and sun exposure so continued maintenance may be needed to prolong the improvement, and often prevention can extend the time between the maintenance visits by reducing the exposure that produces the unwanted blemish. And thirdly, there are things the client will need to do before and after treatment to get the best safe outcome.

Determining the Baseline to
Avoid Complications
The manufacturer’s clinical guidelines apply primarily to the first treatment only. Rather than trusting a single test spot review, after 10 to 15 minutes for a safe treatment level, it is often better to start with a baseline treatment developed by baseline recommendations by the manufacturer and conditioned by user experience. Many use the phrase, “We know the device well, but we do not know your level of response so we will start conservatively to avoid complication.” After that the user needs to understand that reevaluation is based on previous outcome. Immediate success should be gauged by endpoints without complications. Endpoints are isolated controlled collateral trauma. Perifollicular edema or Perifollicular erythema are good examples. Safe and effective outcomes today are keys to safe, effective outcomes on subsequent treatments, thereby providing a guide to how treatment parameters (energy and time) will be adjusted. Laser endpoints for nonablative procedures are often within 10 to 15 minutes. The most common and mildest complication, blistering, can often be seen in that same time frame. Whereas, other complications generally cannot be seen until later. IPLs often take a few hours to demonstrate endpoints. Therefore it is imperative, for the safety of this procedure and the safe settings for the next, to call the client within 24 hours post-procedure to evaluate the outcome. Many determine safe and effective outcome as a hot, stingy (sunburn) sensation for 30 to 45 minutes – followed by a few hours of possible redness spread out at the treatment site. Know the expected post-procedure outcome for your device and treatment, and prepare the client for the follow-up call the next day. The follow-up call will confirm that the series is on track for the best, safe outcome. A challenge today is that we learn endpoints as a safe indication for success. Knowing, again, that the endpoint is a controlled collateral irritation is now being eliminated by better defined energies and pulse times for procedures, and especially the introduction of good controlled cooling of the skin before, during and immediately after the IPL. Good cooling may completely hide the immediate endpoint, making the follow-up call the only gauge of safe success. As we progress through the treatment series, the risk of complication may increase. Often the series requires the pulse times to shorten and the energies to elevate for success with changing the target. Therefore, reconsent before treatments beyond the first are strongly recommended to avoid complication. Ask the same basic questions as the initial consultation and add questions that may indicate a different target, skin response or complication risk than were not seen before. Many will ask before the second treatment and beyond if the client has made any changes or additions in medication, sun exposure or skin applications like lotions or cosmeceuticals. This is important because treatment improvement often prompts the client to start doing other things to improve skin heath and appearance. As a result, make sure to always ask what is new or different, and begin the treatment visit with cleaning the client’s skin, making sure there is nothing on the skin that you cannot see, such as lotion or moisturizer. Sometimes, Nikolsky’s separation, where the epidermis and the dermis are temporarily separated, can be the result of a good, safe treatment. Commonly unseen by just looking, this separation usually resolves in 24 to 36 hours as the skin glues itself back together. However, immediate post-procedure sweating or mechanical irritation like tight clothing can convert the treated site to blistering. If this complication arises, both areas should be avoided for at least one to two days after treatment.
Before you perform your first treatment, have a written complication plan in place, making sure to detail several questions and answers within the document. It is imperative that the document is reviewed and amended at least once a year. How is complication avoided? What cautions or direction does the client need to follow to avoid complication? What actions does the client need to follow if complication is seen? What is the procedure for care of the complication and possible (probable) referral to a physician for review and care? In addition, pre-treatment photographs should also be a mandatory part of a client consultation, for all procedures, especially if there is a high risk of complication then a post-procedure photograph may also be wise.
In closing, know the abilities and limitations of the device you are using. Know your skill level and do not exceed it. Know how to assess skin type and risk. Know how to deal with a complication through consultation, care and possible referral. Know how to preempt the complication by correct selection and use of contraindications and refusal to treat those you question. Be keen to misinformation from the client about things like sun exposure. And always keep your eyes open for abnormal responses and stop immediately if you see something unusual. Stay current on education and compassionate in your attention to the needs of the client.

Patrick Clark has been active in clinical light applications since 1988. In 1992, he was selected as the founding director of the laser program at the University of Texas Southwestern Medical Center at Dallas and the allied hospitals. He is consistently called upon to assist in development, testing, application and safety of light on tissue worldwide. He has direct experience in complete hospital programs, outpatient and freestanding surgery centers, the beginnings of office and spa applications, and the development of light applications for nonprofessional and home use.