Overview of Laser Treatment of Pigmented Lesions
The term LASER is an abbreviation for Light Amplification by Stimulated Emission of Radiation. Essentially, lasers work by using electromagnetic radiation – a type of energy that can take the form of waves – to energize the tiny particles known as electrons. When these electrons calm down from their energized state, they release packets of light, also known as photons. These packets of light travel in a particular pathway called a wavelength. The wavelengths that we can see with our naked eyes fall between 400 and 700 nanometers, but there are many lasers that also use wavelengths we can’t see.
Since their introduction in the medical world in the 1960s, lasers have been adapted for use in many different areas of medicine. One of the key reasons lasers have become so useful in medicine is their ability to target specific colors using different wavelengths. This has been incredibly helpful in treating colored or pigmented skin conditions, like vascular skin lesions (a type of skin growth or spot), unwanted tattoos, and pigmented moles (known as nevi).
Before using lasers to treat pigmented skin conditions, it’s crucial to have a solid understanding of how lasers work, the related terms, and the safety measures involved. It’s also very important to understand the specific skin condition being treated so the right type of laser can be chosen. This discussion aims to give you the basic knowledge you need to understand this process.
Anatomy and Physiology of Laser Treatment of Pigmented Lesions
The way a laser works to bring about changes in our body’s tissue relies on it being soaked up by a certain part of our cells known as a chromophore. When choosing a medical laser, it’s important to know that the depth a laser can reach in the body is related to its wavelength – basically, the smaller the wavelength, the deeper the laser can go. But even the strongest laser won’t change all of the tissue it touches. Instead, a good laser will only affect its target tissue or chromophore.
In the simplest terms, a chromophore is a part of the cell that can absorb a specific type of laser. When a chromophore absorbs a laser, it heats up and causes the tissue to break down in a controlled way. This process doesn’t damage the tissues around the target area. Some common examples of chromophores include water, hemoglobin, melanin, and deoxyhemoglobin, all of which react to different wavelengths of light. Hemoglobin, melanin, and deoxyhemoglobin, are all colored, each in their own unique way.
If we use a laser to heat up chromophores in our body’s tissue, they might go through several changes, depending on the heat level and how long the heat lasts. These changes can include protein denaturation (where proteins lose their structure), bond breakage, or boiling of water within cells. We need to take these factors into consideration when deciding how much heat to apply. Also, it’s important to note, the time it takes for the tissue to cool to half its peak temperature (known as its thermal relaxation time) is directly related to the size of the target. This means small things like blood vessels will take longer to cool than other cellular structures.
Lasers can also produce what we call photomechanical effects, which are related to heat but in a slightly different way. If we apply a laser to a tissue for a short period of time, it causes the tissue to expand quickly, which sends a shockwave through the tissue and causes it to break down. This process can be useful when targeting small things like capillaries (the smallest type of blood vessel) versus larger structures like veins.
In this process, it’s crucial that the laser has a big effect on the chromophore and the tissue immediately around it, but a minimal effect on other tissues. That way inflammation and healing happen in a controlled area without causing damage to nearby areas. To achieve this, it’s important to understand how we measure laser energy. Joules, power, watts, fluence, and irradiance are all key terms. Joules measure the energy delivered by lasers that pulse on and off, power measures how quickly energy is delivered, and watts measure the power. But these terms only measure the amount of energy a laser gives off. They don’t show how intense the laser’s effect is on the skin or other tissues. For this, we use terms like fluence and irradiance. Fluence is used to measure the energy density of pulsed lasers, or in other words, how much energy is delivered within a specific area, which helps to consider how intense the laser is. Irradiance measures the energy delivered to the skin by continuous lasers.
Why do People Need Laser Treatment of Pigmented Lesions
Sometimes, noticeable spots or blemishes known as ‘lesions’ appear on your skin or inside your mouth. They are usually a different color from the surrounding areas because they contain high amounts of pigments, such as hemoglobin, melanin, and deoxyhemoglobin. One of the ways to treat these is by using medical lasers. The color contrast makes it easier for the laser to target and treat these blemishes effectively. With a basic understanding of common colored blemishes, we can determine when to use a laser for treatment.
‘Vascular anomalies’ is a term used to describe different types of spots and growths that usually require attention from a variety of doctors and treatments. Some vascular anomalies have pigments, and are commonly treated with lasers.
A common vascular anomaly in infants is called Infantile Hemangioma or a strawberry or cherry angioma. Just like strawberries and cherries, this tumor appears as a red or reddish-purple raised spot, commonly located in the head and neck region. Infantile Hemangiomas can be superficial and only affect the skin, or they can also be deep and affect the tissues underneath the skin. There are different types of this condition depending on how widespread it is on the body. It’s important to note that unlike other vascular anomalies, Infantile Hemangioma does not grow with the patient. Their growth peaks at around six months of age before entering a resting period. Then, over a span of several years, it gradually shrinks, often leaving a reddish mark on the skin.
Infantile Hemangiomas usually don’t need any treatment and can be left alone until they shrink naturally. However, treatment might be needed if it becomes too large and starts to affect the baby’s appearance or restrict their normal functions, such as blocking their vision or airway. In some situations, these spots can also bleed or create sores, or distort the skin and cartilage.
Another type of vascular anomaly is the Capillary Malformation, or more commonly known as the port-wine stain. These appear as red, lacy and flat spots that are present from birth. With time, if left untreated, they can get raised, become bumpy, and darken to a purplish color. Like most vascular anomalies, they are often seen in the facial and neck areas.
Another common vascular anomaly is Venous Malformations. These appear as soft, blue-tinged spots that can easily enlarge and often grow into the surrounding tissues. Over time, as they become larger and more extensive, surgical removal might cause noticeable loss of function and changes in appearance. Therefore, it might be better to manage them with more conservative measures like laser therapy.
Lastly, there are Arteriovenous Malformations. These are high-risk vascular malformations that can infiltrate and affect multiple tissues and organs. These can be fatal if left untreated. They can also become severely disfiguring. Laser therapies are used to manage them since complete removal is often not possible due to extensive vascular involvement and invasion of surrounding tissues.
Some conditions or syndromes are associated with vascular anomalies. For instance, when dealing with facial Infantile Hemangiomas, it may be necessary to check for a disease called PHACE syndrome. Similarly, a skin condition called Sturge-Weber syndrome is sometimes linked with port-wine stains (capillary malformations) on the upper face. Klippel-Trenaunay syndrome is also associated with venous malformations when seen along with capillary malformations and excessive growth in limbs. If a patient has Parkes Weber syndrome, they may have Arteriovenous Malformations in addition to capillary malformations and limb overgrowth.
Another type of capillary proliferation is the Pyogenic Granuloma, also known as lobular capillary hemangioma, a benign skin growth that may appear suddenly. Often it is seen on the mucosal surfaces in the head and neck region. Female hormones might aggravate them during pregnancy.
When a Person Should Avoid Laser Treatment of Pigmented Lesions
Being pregnant doesn’t mean that you cannot have a skin laser therapy. In the past, doctors often deferred such treatments until after the baby was born because they were afraid it might harm either the mother or the baby. Recent research, however, has shown that skin laser therapies do not pose any significant risks to the baby at any stage of pregnancy.
Similarly, having dark skin doesn’t completely rule out the possibility of having laser therapy. It does, however, make the risk of scarring worse due to the higher chance of pigmentation changes and scarring that dark complexions have. Further discussions on this matter are available in the “Issues that can arise” section.
Regarding the treatment of pigmented nevi (commonly known as moles) with lasers, there’s a bit of a debate. It can make it harder to monitor a mole for any changes in color or size, which could indicate malignancy (development of cancer). Therefore, any mole that looks suspicious for being malignant should not be treated with lasers. Patients with moles should be regularly monitored for any changes.
Equipment used for Laser Treatment of Pigmented Lesions
A laser is a kind of light source that is extremely focused and controlled. This light has a single color and it travels in one direction over long distances without spreading out. The essential parts of a laser are located in a special chamber. This chamber contains a strong energy source and mirrors. The mirrors bounce the light energy around and intensify it, creating what we call a laser beam. One of the mirrors is partially see-through, which lets the extremely focused light escape as the laser beam. This beam can be aimed accurately and can either remain on (continuous) or flash on and off (pulsed).
To use a laser more precisely, there are tools to help control where the beam goes. Some lasers create light that humans can’t see. In this case, a visible ‘aiming beam’ is used to show where the invisible laser is pointed. Aiming beams can also be guided through fiber optic cables to work in hard-to-reach places.
Another important part of working with lasers is cooling. Some lasers generate heat, which can cause discomfort and even harm the skin. Cooling devices can protect the skin by reducing the heat produced by the laser. There are different ways to cool the skin, like cooling before, during or after the laser contact. One method is called contact cooling, where something cold is physically touching the skin to take away the heat. These could be metal parts attached to the laser, or even cold gels or ice packs. Another method doesn’t involve direct contact and works by blowing cold air or spraying a cooling liquid on the skin, which help take away heat by causing it to evaporate.
Who is needed to perform Laser Treatment of Pigmented Lesions?
When a doctor uses a laser for your treatment, they aren’t working alone. They are part of a special team called the “laser team”. These team members are trained in how lasers work and how to use them safely. They must be familiar with the rules of laser safety.
Now, the person using the laser, called the “laser operator,” should have special training too. They need to complete a certified course that specifically teaches them about laser safety.
Then, there is a very important person on the team called the “laser safety officer” (LSO). This role was established in the late 1990s. Their job is to handle anything to do with laser safety in the hospital. They also manage any risks that might come with using the laser. The LSO stays in contact with everyone in the hospital who will be dealing with the laser.
Preparing for Laser Treatment of Pigmented Lesions
When having a laser treatment, protecting the eyes – of both the patient and the medical team – is extremely important. This why everyone in the room during the procedure should wear special safety goggles. These are specifically designed to protect against the type of light being used in the treatment. The goggles should fit well and feel comfortable.
Patients who are getting laser treatment near their face or eyes will also need to use eye shields for added protection. These shields are usually made of metal or plastic and are placed over the eyes to protect them during the procedure. It’s important to note that while eye injuries can happen with these shields, you’re more likely to get an injury without them.
In terms of managing pain during the laser treatment, a benefit of this procedure is that it can often be done without heavy-duty anesthesia. This means you can often have it done in a regular doctor’s office rather than having to go to a hospital. To help control the pain, your doctor can apply special creams or do a local nerve block, which blocks pain from a specific area.
However, there might be times when these local anesthetics aren’t enough to manage the pain, especially in children. In these cases, your doctor will talk to you and your child about the possibility of using general anesthesia, which puts you to sleep so you don’t feel pain during the procedure.
Finally, to help control the heat and limit actal damage during the laser procedure, the area being treated can be cooled. This can be done with a special device, or simply with ice packs applied after the treatment. This helps to soothe the area and speed up recovery.
How is Laser Treatment of Pigmented Lesions performed
Two types of lasers are used to diminish red and blue skin blemishes including birthmarks (infantile hemangiomas, capillary malformations, arteriovenous malformations, pyogenic granulomas) and tattoos: the flash pulsed/pump dye laser (FPDL) and the Neodymium: yttrium aluminum garnet (Nd: YAG) laser.
The FPDL targets oxyhemoglobin, a substance in our blood that gives it its red color and is particularly effective at treating red skin blemishes. This laser works best for lesions close to the skin surface because it can only penetrate about 1.2mm deep. The size and intensity of the laser beam can be adjusted for different effects. Since the laser heat can cause damage to skin cells, it’s important to use a coolant, like a spray, during treatments to protect the skin. Though one treatment is often not enough, several sessions may significantly fade the red pigment of a skin lesion.
In contrast, the Nd: YAG laser is typically used to treat blue lesions, or venous malformations. This laser is effective because it specifically targets deoxyhemoglobin, a blue substance found in venous blood. Unlike the FPDL, the Nd: YAG laser can penetrate deeper into the skin, reaching up to 5-6mm, and it also possesses blood clotting properties. When treating the skin, there is a variant of the Nd: YAG laser called the Gentle YAG laser which delivers a cryogen spray as a coolant to prevent skin damage from the heat. For treatment inside the mouth where a coolant is not used, the laser is delivered on a fiber placed close to the tissue. You can see the targeted area shrink right after the treatment. Just like with red lesions, blue lesions generally require repeated treatments as well.
The same Nd: YAG laser, as well as others such as the Q-switched ruby laser and the Q-switched alexandrite laser, are also commonly used for tattoo removal. Different lasers are needed to target different tattoo ink colors in the skin. The detailed process of how lasers fade tattoos is still unclear, but it’s thought that they might shatter the tattoo pigments by using heat, chemicals or vibrations, thus changing the way these color pigments look.
Laser treatments are also employed in the removal of nevi—the medical term for moles. When removing nevi, doctors use either non-specific lasers or specific lasers. Non-specific lasers target water, a common component of human tissue, and are used to resurface the entire uppermost layer of the skin. Specific lasers, on the other hand, target pigment cells in the skin and break them down. Some of the specific lasers used include the Q-switched ruby laser, the Q-switched alexandrite laser, and the Nd: YAG laser. During the treatment, the intensity and spot size of the lasers can be varied just like when treating vascular anomalies. Typically, deeper lesions require larger spot sizes and higher energy levels for better penetration.
Possible Complications of Laser Treatment of Pigmented Lesions
Lasers used in medical treatments can sometimes inadvertently harm the eye, an outcome that is commonly known as ocular damage. Some lasers, like the Nd: YAG laser, are absorbed by the dark pigment, melanin, in the retina, which can lead to bleeding or scarring in the eye. Other lasers can harm the lens and the outer surface of the eye, particularly if the laser beam is invisible or barely visible. Research highlights the necessity for protective eye wear, like shields and safety goggles, to minimize such risks.
Lasers can also cause unwanted changes to the skin. Some changes, like temporary redness and small patches of minor skin bleeding (known as purpura), are normal. But skin blistering, scarring, and changes in skin color are not expected and happen due to the heat injury caused by lasers. To minimize these risks, doctors often test how a small area of skin reacts to the laser before treating the entire affected area. It’s also important for doctors to explain to patients what skin changes are normal after laser treatment. For example, if a QSRL laser is used, the skin area may turn white initially. This change usually fades within minutes. Patients should also expect swelling, redness, skin peeling, and flaking about a week or so after the treatment.
Patients with darker skin need to be aware that they might experience more side effects from laser treatments. This happens because melanin, the pigment that gives skin, hair, and eyes their color, absorbs laser energy leading to a heat injury. Also, the abundance of melanin in darker skin can reduce the effectiveness of laser treatments aimed at coloring issues. However, patients with deeply pigmented skin can still undergo laser treatments with certain precautions. Mainly, lasers with longer wavelengths should be used as they are absorbed less by melanin and can penetrate more deeply into the skin. The important point to understand here is that melanin’s absorption of laser energy decreases as the wavelength of the laser increases. Therefore, for patients with darker skin, lasers with longer wavelengths should be used whenever possible.
What Else Should I Know About Laser Treatment of Pigmented Lesions?
Laser therapy is a technique that uses a gentle procedure to handle colored or pigmented marks that appear on the skin or the mucosa, the soft tissue that lines the inside of certain body parts. Laser therapy has been proved useful in managing the growth of vascular abnormalities, which are unusual blood vessel formations. These could otherwise lead to distorted body features or problems in functioning if not treated.
Besides vascular anomalies, lasers can effectively treat other pigmented lesions. These might not be growing or getting worse, but they could still make patients feel self-conscious about their appearance. Therefore, for any healthcare provider caring for patients with pigmented lesions, laser therapy is an essential tool to have in their toolkit. It’s a simple and effective way to manage these conditions, offering patients relief from both physical and emotional discomfort.