Tattoo removal
Encyclopedia
Tattoo removal has been performed with various tools during the history of tattooing. While tattoo
Tattoo
A tattoo is made by inserting indelible ink into the dermis layer of the skin to change the pigment. Tattoos on humans are a type of body modification, and tattoos on other animals are most commonly used for identification purposes...

s were once considered permanent, it is now possible to remove them with treatments, fully or partially. The expense and pain of removing tattoos will typically be greater than the expense and pain of applying them.

Pre-laser tattoo removal methods include dermabrasion
Dermabrasion
Dermabrasion is a surgical procedure that involves the controlled abrasion of the upper layers of the skin with sandpaper or other mechanical means. Nowadays it has become common to use CO2 or Erbium:YAG laser as well. The procedure requires a local anaesthetic...

, salabrasion (scrubbing the skin with salt
Salt
In chemistry, salts are ionic compounds that result from the neutralization reaction of an acid and a base. They are composed of cations and anions so that the product is electrically neutral...

), cryosurgery
Cryosurgery
Cryosurgery is the application of extreme cold to destroy abnormal or diseased tissue. The term comes from the Greek words cryo and surgery meaning "hand work" or "handiwork"....

 and excision
Excision
Excision is the alias of Jeff Abel, a dubstep DJ and music boss from British Columbia, Canada. He frequently works with fellow Canadian dubstep producers Datsik and Downlink. As one of the first dubstep producers and DJs in North America, he has played a significant role in the genre's growth in...

 which is sometimes still used along with skin grafts for larger tattoos. Some early forms of tattoo removal included the injection or application of wine, lime, garlic or pigeon excrement. Tattoo removal by laser
Laser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of photons. The term "laser" originated as an acronym for Light Amplification by Stimulated Emission of Radiation...

 was performed with continuous-wave lasers initially, and later with Q-switched lasers, which became commercially available in the early 1990s. Today, "laser tattoo removal" usually refers to the non-invasive removal of tattoo pigments using Q-switched lasers. Typically, black and darker colored inks can be removed more completely.

Motivation for tattoo removal

In the United States, about 17% of people with tattoos experience some regret. According to a poll done in 2008, the most common reasons for regret are "too young when I got the tattoo" (20%), it's "permanent" and I'm "marked for life" (19%), and I just "don't like it" (18%). An earlier poll showed that 19% of British people with tattoos suffered regret, as did 11% of Italian people with tattoos. Surveys of tattoo removal patients were done in 1996 and 2006 and provided more insight. These patients typically obtained their tattoos in their late teens or early twenties, and just over half were women. About 10 years later, the patient's life had changed, and more than half of the patients reported that they "suffered embarrassment." A new job, problems with clothes, and a significant life event (wedding, divorce, baby) were also commonly cited as motivations.

Cover-up

Some wearers decide to cover an unwanted tattoo with a new tattoo. This is commonly known as a cover-up. An artfully done cover-up may render the old tattoo completely invisible, though this will depend largely on the size, style, colors and techniques used on the old tattoo and the skill of the tattoo artist. Covering up a previous tattoo necessitates darker tones in the new tattoo to effectively hide the older, unwanted piece. Many tattoos are too bright to cover up and in those cases patients may receive laser tattoo removal to lighten the existing ink to make themselves better candidates for a cover up tattoo.

Methods

Tattoo removal is most commonly performed using lasers that react with the ink in the tattoo and break it down. The broken-down ink is then absorbed by the body, mimicking the natural fading that time or sun exposure would create. All tattoo pigments have specific light absorption spectra. A tattoo laser must be capable of emitting adequate energy within the given absorption spectrum of the pigment to provide an effective treatment. Certain tattoo pigments, such as yellows, greens and fluorescent inks are more challenging to treat than darker blacks and blues. These pigments are more challenging to treat because they have absorption spectra that fall outside or on the edge of the emission spectra available in the tattoo removal laser.

Widely considered the gold standard treatment modality to remove a tattoo, laser tattoo removal requires repeat visits. The newer Q-switched lasers are said by the National Institutes of Health
National Institutes of Health
The National Institutes of Health are an agency of the United States Department of Health and Human Services and are the primary agency of the United States government responsible for biomedical and health-related research. Its science and engineering counterpart is the National Science Foundation...

 to result in scarring only rarely and are usually used only after a topical anesthetic
Topical anesthetic
A topical anesthetic is a local anesthetic that is used to numb the surface of a body part. They can be used to numb any area of the skin as well as the front of the eyeball, the inside of the nose, ear or throat, the anus and the genital area. Topical anesthetics are available in creams,...

 has been applied. Areas with thin skin will be more likely to scar than thicker-skinned areas. There are several types of Q-switched lasers, and each is effective at removing a different range of the color spectrum
Visible spectrum
The visible spectrum is the portion of the electromagnetic spectrum that is visible to the human eye. Electromagnetic radiation in this range of wavelengths is called visible light or simply light. A typical human eye will respond to wavelengths from about 390 to 750 nm. In terms of...

. Lasers developed after 2006 provide multiple wavelengths and can successfully treat a much broader range of tattoo pigments than previous Q-switched lasers.

Another type of tattoo removal is the manual, or machine method. This practice is very unpredictable and uses a specialized type of gel, commonly mixed with saline, which is tattooed into the skin over the tattoo causing the ink in the dermis to bond with or be displaced by the gel and migrate to the surface of the epidermis. The incidence of scarring, tissue texture changes, keloids, prolonged healing, pain, discoloration (hyper- and hypopigmentation) and ink retention is extremely high with non-laser removal method; the person performing this treatment modality exposes him or herself to considerable liability. Methods like this are now only very rarely performed and in modern countries have been replaced by Q-switched laser treatment. Still other methods including thermal injury, dermabrasion and cryotherapy, are used but with the same unpredictable results and adverse side effects.

Mechanism of laser action

Experimental observations of the effects of short-pulsed lasers on tattoos were first reported in the late 1960s. In 1979 an argon laser was used for tattoo removal in 28 patients, with limited success. In 1978 a carbon dioxide was also used, but generally caused scarring after treatments It was not until the late 1980s that Q-switched lasers became commercially practical. One of the first published articles describing laser tattoo removal was authored by a group at Massachusetts General Hospital
Massachusetts General Hospital
Massachusetts General Hospital is a teaching hospital and biomedical research facility in the West End neighborhood of Boston, Massachusetts...

 in 1990.

Tattoos consist of thousands of particles of tattoo pigment suspended in the skin. While normal human growth and healing processes will remove small foreign particles from the skin, tattoo pigment particles are permanent because they are too big to be removed. Laser treatment causes tattoo pigment particles to heat up and fragment into smaller pieces. These smaller pieces are then removed by normal body processes.

Laser tattoo removal is a successful application of the theory of selective photothermolysis (SPTL). For laser tattoo removal, SPTL for the selective destruction of tattoo pigments depends on four factors:
  • The color of the light must penetrate sufficiently deep into the skin to reach the tattoo pigment.
  • The color of the laser light must be more highly absorbed by the tattoo pigment than the surrounding skin. Different tattoo pigments therefore require different laser colors. For example, red light is highly absorbed by green tattoo pigments.
  • The time duration (pulse duration) of the laser energy must be very short, so that the tattoo pigment is heated to fragmentation temperature before its heat can dissipate to the surrounding skin. Otherwise, heating of the surrounding tissue can cause burns or scars. For laser tattoo removal, this duration should be on the order of nanoseconds.
  • Sufficient energy must be delivered during each laser pulse to heat the pigment to fragmentation. If the energy is too low, pigment will not fragment and no removal will take place.


Q-switched lasers are the only commercially available devices that can meet these requirements.

Laser parameters that affect results

Several colors of laser light (measured as wavelengths of laser energy) are used for tattoo removal, from visible light to near-infrared radiation. Different lasers are better for different tattoo colors. Consequently, multi-color tattoo removal almost always requires the use of two or more laser wavelengths. Tattoo removal lasers are usually identified by the lasing medium used to create the wavelength (measured in nanometers (nm)):
  • Q-switched Frequency-doubled Nd:Yag: 532 nm. This laser creates a green light which is highly absorbed by red and orange targets. Useful primarily for red and orange tattoo pigments, this wavelength is also highly absorbed by melanin (the chemical which gives skin color or tan) which makes the laser wavelength effective for age spot or sun spot removal.
  • Q-switched Ruby: 694 nm. This laser creates a red light which is highly absorbed by green and dark tattoo pigments. Because it is more highly absorbed by melanin this laser may produce undesirable side effects such as pigmentary changes for patients of all but white skin.
  • Q-switched Alexandrite: 755 nm. Similar to the Ruby laser, the Alexandrite creates a red light which is highly absorbed by green and dark tattoo pigments. However, the alexandrite laser color is slightly less absorbed by melanin, so this laser has a slightly lower incidence of unwanted pigmentary changes than a ruby laser.
  • Q-switched Nd:YAG: 1064 nm. This laser creates a near-infrared light (invisible to humans) which is poorly absorbed by melanin
    Melanin
    Melanin is a pigment that is ubiquitous in nature, being found in most organisms . In animals melanin pigments are derivatives of the amino acid tyrosine. The most common form of biological melanin is eumelanin, a brown-black polymer of dihydroxyindole carboxylic acids, and their reduced forms...

    , making this the only laser suitable for darker skin. This laser wavelength is also absorbed by all dark tattoo pigments and is the safest wavelength to use on the tissue due to the low melanin absorption and low hemoglobin
    Hemoglobin
    Hemoglobin is the iron-containing oxygen-transport metalloprotein in the red blood cells of all vertebrates, with the exception of the fish family Channichthyidae, as well as the tissues of some invertebrates...

     absorption. This is the wavelength of choice for tattoo removal in darker skin types.
  • Dye modules are available for some lasers to convert 532 nm to 650 nm or 585 nm light which allows one laser system to safely and effectively treat multi-color tattoo inks.


Pulsewidth or pulse duration is a critical laser parameter. All q-switched lasers have appropriate pulse durations for tattoo removal. However, lasers with a shorter pulses have a safer and more efficient removal method because the peak power of the pulse is greater.

Spot size, or the width of the laser beam, affects treatment. Light is optically scattered in the skin, like automobile headlights in fog. Larger spot sizes slightly increase the effective penetration depth of the laser light, thus enabling more effective targeting of deeper tattoo pigments. Larger spot sizes also help make treatments faster.

Fluence or energy level is another important consideration. Fluence is measured in joules per square centimeter (J/cm²). Its important to get treated at high enough settings to fragment tattoo particles.

Repetition rate helps make treatments faster but is not associated with any treatment effect.

Number of laser tattoo removal treatment sessions needed

Complete laser tattoo removal requires multiple treatment sessions, typically spaced at least eight weeks apart. At each session, some but not all of the tattoo pigment particles are effectively fragmented, and the body removes the smallest fragments over the course of several weeks. The result is that the tattoo is lightened over time. Remaining large particles of tattoo pigment are then targeted at subsequent treatment sessions, causing further lightening. The number of sessions and spacing between treatments depends on various parameters, including the area of the body treated and skin color. Tattoos located on the extremities, such as the ankle, generally take longest. As tattoos fade clinicians may recommend that patients wait many months between treatments to facilitate ink resolution and minimize unwanted side effects.

The amount of time required for the removal of a tattoo and the success of the removal varies with each individual. Factors influencing this include: skin type, location, color, amount of ink, scarring or tissue change, and layering. In the past health care providers would simply guess on the number of treatments a patient needed which was rather frustrating to patients. A predictive scale, the "Kirby-Desai Scale", was developed by Dr. Will Kirby and Dr. Alpesh Desai, dermatologists with specialization in tattoo removal techniques, to assess the potential success and number of treatments necessary for laser tattoo removal, provided the medical practitioner is using a quality-switched Nd:YAG (neodymium-doped yttrium aluminum garnet) laser incorporating selective photothermolysis with eight weeks between treatments.

The Kirby-Desai Scale assigns numerical values to six parameters: skin type, location, color, amount of ink, scarring or tissue change, and layering. Parameter scores are then added to yield a combined score that will show the estimated number of treatments needed for successful tattoo removal. Experts recommend that the Kirby-Desai scale be used by all laser practitioners prior to starting tattoo removal treatment to help determine the number of treatments required for tattoo removal and as a predictor of the success of the laser tattoo removal treatments. Prior to 2009, clinicians had no scientific basis by which to estimate the number of treatments needed to remove a tattoo and the use of this scale is now standard practice in laser tattoo removal.

Factors contributing to the success of laser tattoo removal

Multiple factors contribute to the success of laser tattoo removal one of which is a patient's own immune system. A healthy patient will get the best results. Adequate hydration, eight hours of sleep a night, maintaining a healthy weight, eating a well balanced diet, exercise, and non-smoking improve results. Treatment on some patients with immune systems problems are contraindicated.

Pain management during treatment

Laser tattoo removal can be uncomfortable but is very tolerable in most cases. The pain is often described to be similar to that of hot oil on the skin, or a 'slap' from an elastic band. Depending on the patient's pain threshold, and while some patients may forgo anesthesia altogether, most patients will require some form of local anesthesia. Pre-treatment might include the application of an anesthetic cream under occlusion for 45 to 90 minutes prior to the laser treatment session. In very rare cases, if complete anesthesia is necessary, it can be administered locally by injections of 1% to 2% lidocaine with epinephrine.

Anecdotal reports have noted that patients receiving anesthesia by local injection will require additional treatments as the injection causes mechanical edema, spreading out the tattoo ink, which in turn makes it more difficult for the laser light to act on specific ink particles. It has been reported that infiltration of local anesthesia will add an additional treatment or two.

Post-treatment considerations

Immediately after laser treatment, a slightly elevated, white discoloration
with or without the presence of punctuate bleeding is often observed. This white color change is thought to be the result of rapid, heat-formed steam or gas,
causing dermal and epidermal vacuolization. Pinpoint bleeding represents vascular injury from photoacoustic waves created by the laser's interaction with tattoo pigment. Minimal edema and erythema of adjacent normal skin usually resolve within 24 hours. Subsequently, a crust appears over the entire tattoo, which sloughs off at approximately 14 days post treatment. As noted above, some tattoo pigment may be found within this crust. Post-operative wound care consists of topically applied antibiotic ointment and a non-occlusive dressing.
Fading of the tattoo will be noted over the next eight weeks and re-treatment energy levels can be tailored depending on the clinical response observed.

Side effects and complications

About half of the patients treated with Q-switched lasers for tattoo removal will show some transient changes in the normal skin pigmentation. These changes usually resolve in 6 to 12 months but may rarely be permanent.

Hyperpigmentation is related to the patient's skin tone, with skin types IV,V and VI more prone regardless of the wavelength used. Twice daily treatment with hydroquinones and broad-spectrum sunscreens usually resolves the hyperpigmentation within a few months, although, in some patients, resolution can be prolonged.

Transient textural changes are occasionally noted but often resolve within a few months, however, permanent textural changes and scarring very rarely occur. If a patient is prone to pigmentary or textural changes, longer treatment intervals are recommended. Additionally, if a patient forms a blister or crust post treatment, it is imperative that they do not manipulate this secondary skin change. Early removal of a blister of crust increases the chances of developing a scar. Additionally, patients with a history of hypertrophic or keloidal scarring need to be warned of their increased risk of scarring.

Local allergic responses to many tattoo pigments have been reported, and allergic reactions to tattoo pigment after Q-switched laser treatment are also possible. Rarely, when yellow cadmium sulfideis used to "brighten" the red or yellow portion of a tattoo, a photoallergic reaction may occur. The reaction is also common with red ink, which may contain cinnabar (mercuric sulphide). Erythema, pruritus, and even inflamed nodules, verrucose papules, or granulomas may present. The reaction will be confined to the site of the red/yellow ink. Treatment consists of strict sunlight avoidance, sunscreen, interlesional steroid injections, or in some cases, surgical removal. Unlike the destructive modalities described, Q-switched lasers mobilize the ink and may generate a systemic allergic response. Oral antihistamines and anti-inflammatory steroids have been used to treat allergic reactions to tattoo ink.

Studies of various tattoo pigments have shown that a number of pigments (most containing iron oxide or titanium dioxide) change color when irradiated with Q-switched laser energy. Some tattoo colors including flesh tones, light red, white, peach and light brown containing pigments as well as some green and blue tattoo pigments, changed to black when irradiated with Q-switched laser pulses. The resulting gray-black color may require more treatments to remove. If tattoo darkening does occur, after 8 weeks the newly darkened tattoo can be treated as if it were black pigment.

Very rarely, non Q-switched laser treatments, like CO2 or Argon lasers, which are very rarely offered these days, can rupture blood vessels and aerosolizes tissue requiring a plastic shield or a cone device to protect the laser operator from tissue and blood contact. Protective eye-wear may be worn if the laser operator choose to do so.

With the mechanical or salabrasion method of tattoo removal, the incidence of scarring, pigmentary alteration (hyper- and hypopigmentation),and ink retention are extremely high.

The use of Q-switched lasers could very rarely produce the development of large bulla. However, if patients follow post care directions to elevate, rest, and apply intermittent icing, it should minimize the chances of bulla and other adverse effects. In addition, health care practitioners should contemplate the use of a cooling device during the tattoo removal procedure. While the infrequent bulla development is a possible side effect of Q-switched laser tattoo removal, if treated appropriately and quickly by the health care practitioner, it is unlikely that long term consequences would ensue.

Risks

Although laser treatment is gold standard method to remove a tattoo, unwanted side effects of laser tattoo removal include the possibility of discoloration of the skin such as hypopigmentation (white spots, more common in darker skin) and hyperpigmentation (dark spots) as well as textural changes. Very rarely, burns may result in scarring but this usually only occur when patients don't care for the treated area properly. Rarely, "paradoxical darkening" of a tattoo may occur, when a treated tattoo becomes darker instead of lighter. This seems to occur more often with flesh tones, pink, and cosmetic make-up tattoos.

Some tattoo pigments contain metals that could theoretically break down into toxic chemicals in the body when exposed to light. This has not yet been reported in vivo but has been shown in the lab;. Laser removal of traumatic tattoos may similarly be complicated depending on the substance of the pigmenting material. In one reported instance, the use of a laser resulted in the ignition of embedded particles of firework debris.

Further reading

  • Kirby W, Kartono F, Small R. (September 2011). "Chapter 30: Tattoo Removal with Lasers. Dermatologic and Cosmetic Procedures in Office Practice". Elsevier. pp: 367-376. ISBN 978-1-4377-0580-5
  • Wysong P, "Tattoo Removal Comes Of Age - An Expert Interview With Dr. William Kirby and Dr. Rady Rahban" Medscape, August 16, 2011 http://www.medscape.com/viewarticle/747828
  • Kirby W, Kartono F, Desai A, Kaur R, Desai T, Treatment of Large Bulla Formation after Tattoo Removal with a Q-Switched Laser,Journal of Clinical and Aesthetic Dermatology, January,2010 http://www.jcadonline.com/2210/treatment-of-large-bulla-formation-after-tattoo-removal-with-a-q-switched-laser/#more-2210
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