Tattoo Removal with Lasers

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30 Tattoo Removal with Lasers

William Kirby, DO, FAOCD, Francisca Kartono, DO, and Rebecca Small, MD

The growing trend of tattooing has led to increased numbers of patients seeking tattoo removal. Studies note that 40% of Americans between the age of 26 and 40 currently have tattoos and 17% of these people are seeking removal.^1,² With more than 20,000 tattoo studios in the United States placing tattoos, the demand for removal is likely to continue to increase in the coming years.³

Multiple techniques can be used for tattoo removal. Early removal methods used mechanical destruction such as dermabrasion, chemical peels, and continuous-wave lasers. These methods left patients with unsatisfactory results and were associated with suboptimal removal and scarring (Figure 30-1). The current standard of using Q-switched lasers has revolutionized tattoo removal and offers patients a safe and effective means for removing tattoo ink.

FIGURE 30-1 Dermabrasion results for tattoo removal showing scarring, hypopigmentation, and residual ink.

(Copyright Rebecca Small, MD.)

In this chapter, we describe the physiology of a tattoo, the latest tattoo removal technology, and the current standard practice recommendations for tattoo removal with Q-switched lasers.

Tattoo Anatomy

During the tattooing process, tattoo ink is injected intradermally. The epidermis and upper papillary dermis are homogenized and ink particles (ranging in size from 2 to 400 nm) are deposited intracellularly and extracellularly. After 2 to 3 months, the skin layers are reestablished and ink is concentrated in the dermis within fibroblasts, beneath a layer of fibrotic scar tissue (Figure 30-2).

FIGURE 30-2 Tattoo placement and dermal incorporation of ink (A) immediately after tattooing, (B) 1 month, and (C) 2 to 3 months after.

Numerous chemicals and inks are used in the tattoo industry and the component ink compounds in a given tattoo are usually unknown by the patient at the time of presenting for tattoo removal. The Food and Drug Administration (FDA) does not regulate tattoo inks and, therefore, tattoo inks are not evaluated for safety. In general, amateur tattoos are often carbon based such as burnt wood or pen ink, and there is a lower density of pigment particles. Professional tattoos are typically composed of organic dyes mixed with metallic elements that give the color: red is often made from mercury; yellow from cadmium; green from chromium; blue from cobalt; white from titanium dioxide; and flesh color from iron oxide. Tattoo inks are usually combinations of colors, so a green, red, or light blue tattoo may also contain darker colors such as black ink.

Laser Principles

Tattoo ink serves as a cutaneous chromophore for lasers. Certain wavelengths of light are selectively absorbed by different ink colors.⁴ In this way, colored inks can be targeted and removed by laser light with minimal damage to surrounding tissues. The chromophore absorption spectrum of the tissue chromophores, melanin and oxyhemoglobin, as well as wavelengths used for tattoo removal, are shown in Figure 30-3. Wavelength selection for different tattoo colors is shown in Figure 30-4 and is as follows:

FIGURE 30-3 Chromophore absorption spectra and tattoo removal lasers.

FIGURE 30-4 Laser wavelengths used for different tattoo colors.

(Copyright Rebecca Small, MD.)

• Black and dark blue inks are best treated with a 1064 nm wavelength.

• Red ink (and variations of red such as orange and yellow) is best treated with a 532 nm wavelength.

• Green ink is best treated with 650, 694, or 755 nm wavelengths.

• Sky blue is best treated with a 585 nm wavelength.

• Purple is a combination color and can be treated with 585 and 532 nm wavelengths.

Laser parameters including wavelength, pulse duration, and fluence can be tailored to maximize tattoo ink destruction and minimize thermal damage to surrounding tissue. Short pulsed, Q-switched lasers further employ photoacoustic vibration to fragment tattoo ink into smaller particles. These smaller ink particles are eliminated through epidermal extrusion, lymphatic drainage, and macrophage phagocytosis. In addition, laser-treated ink particles have altered optical properties that render the ink remaining in the skin less visible to the eye.⁵

Laser Parameters and Tattoo Treatments

• Pulse width, or pulse duration (measured in nanoseconds) is the length of time that laser light is in contact with the skin. Q-switched lasers have fixed nanosecond pulse widths and this parameter cannot be adjusted for treatments.

• The thermal relaxation time (measured in seconds) is defined as the time required for the absorbed energy within the target chromophore to cool to one-half its original value immediately after irradiation. To specifically target the chromophore ink and reduce unwanted thermal damage to surrounding tissues, very short pulse widths (shorter than the target thermal relaxation time) are used to heat and ablate the ink faster than heat is conducted to the surrounding tissue.

• Spot size (measured in millimeters) is the diameter of the laser beam on the skin surface. Use of a larger spot size results in less scatter of the photons and deeper laser beam penetration. This maximizes the distribution of laser light to the dermal ink and reduces epidermal injury. Larger spot sizes should be used as long as sufficient fluence can be obtained to achieve the desired clinical endpoint. A smaller spot size (e.g., 2 to 3 mm) has greater scattering of photons, delivers energy less efficiently, and causes more epidermal injury than larger spot sizes (e.g., 6 to 8 mm).

• Wavelength (measured in nanometers) is chosen based on the tattoo ink color. In general, as the wavelength increases, so does the depth of penetration.

• The energy output is known as fluence (measured in joules per square centimeter). More specifically, fluence is defined as the amount of energy delivered per unit area. Fluence should be sufficient to produce immediate whitening with tattoo treatment without bleeding or blistering. The fluence emitted with a given spot size is dependent on the device used. Adequately powered tattoo laser devices can maintain high fluences (e.g., more than 4.5 J/cm²) with large spot sizes (e.g., 6 mm).

Patient and Tattoo Selection

Lasers may be used for tattoo removal in patients of all skin types (Fitzpatrick types I through VI). However, patients with darker skin types (IV through VI) are at greater risk for side effects, specifically hypopigmentation and hyperpigmentation. Topical hydroquinone (2% to 8%) can be used preprocedure, and resumed once the skin is healed postprocedure, to reduce the risk of postinflammatory hyperpigmentation in patients with darker skin types. Additionally, patients of Asian or African descent have a greater predisposition to hypertrophic and keloidal scarring. In general, Fitzpatrick skin type VI patients have the greatest risk of complications with any aesthetic procedure, and providers should consider treatment of this skin type an advanced laser application.

Almost any tattoo is indicated for laser tattoo removal. Multiple treatments are needed to achieve satisfactory results. Due to great variation in tattoo ink depth, density, composition, and techniques used for placement, the number of treatments needed for removal can be difficult to estimate accurately. In general, professionally placed tattoos have a high ink density and require 9 to 14 treatments, whereas amateur tattoos typically require 4 to 8 treatments. Several other factors can affect the number of treatments necessary for removal: faded, older tattoos on paler skin types in more proximal locations tend to resolve with fewer treatments than intense, multicolored tattoos on darker skin types in distal locations.⁶ Patients should be questioned about other tattoo removal methods used previously. Methods that create scar tissue, such as burning or abrasion, can make tattoo removal with lasers less successful.

Certain types of tattoos are considered advanced, and treatment should not be undertaken until the provider is fully confident in his or her skill with artistic tattoo removal. Advanced tattoos include cosmetic tattoos, such as those used for permanent eyeliner or lip liner, flesh-colored inks, and traumatic tattoos.

Indications

Laser tattoo removal is indicated for the treatment of ectopic skin pigment. This pigment is usually from purposefully placed ink in tattoos (both professional and amateur artistic tattoos) as well as tattoos associated with medical procedures (e.g., radiation therapy tattoos). In rare cases ectopic pigment may be the result of trauma (traumatic tattoos) where materials such as asphalt are trapped in the dermis.

Alternative Therapies

The following alternatives to Q-switched laser tattoo removal methods are not recommended:

• Dermabrasion (not to be confused with microdermabrasion)

• Salabrasion

• Cryotherapy (liquid nitrogen)

• Continuous-wave lasers

• Chemical acids

• Thermal injury (electrocautery).

The results of using these alternative modalities are often unsatisfactory to both patients and health care professionals. These techniques significantly increase the risk of adverse effects including scarring, hypopigmentation, hyperpigmentation, depigmentation, incomplete resolution of ink, pain, prolonged healing time, infection, textural changes, and unpredictable outcomes. The advantage of these techniques is that they are relatively inexpensive and may offer faster ink resolution when compared to laser tattoo removal treatments. Some providers use surgical excision as a method of tattoo removal.

Products Currently Available

Q-switched lasers are now widely regarded as the gold standard for laser tattoo removal. Current Q-switched lasers available include:

• Q-switched Nd:YAG laser (1064 nm)

• Frequency doubled (532 nm)

• Dye modules (650 nm and 585 nm)

• Q-switched alexandrite laser (755 nm)

• Q-switched ruby laser (694 nm).

The Q-switched Nd:YAG (neodymium-doped yttrium aluminum garnet) produces a 1064 nm wavelength of light that is ideal for treating black ink. A primary disadvantage is its limited efficacy in removing yellow and green inks. With some devices, through a process called frequency doubling, an Nd:YAG laser can also produce light with a wavelength of 532 nm to treat red, orange, and yellow inks.²⁰ The Nd:YAG laser has an advantage of treating darker skinned patients with less risk of hypopigmentation, hyperpigmentation, and textural changes.⁷ This can be attributed to the increased dermal penetration of this longer wavelength and the lower melanin absorption. The wavelength of the light emitted by the Q-switched alexandrite laser is 755 nm. This wavelength has excellent absorption by black, good absorption by green and blue, but poor absorption by red ink. The ruby laser was one of the first Q-switched lasers, and it emits a 694 nm wavelength. It works well for darker colors (black, blue-black, and some green), but poorly on yellow and red ink. Although more effective for green ink than the Nd:YAG, the ruby laser commonly causes hypopigmentation and hyperpigmentation and, although usually transient, may be permanent.⁵

Recently, a number of lower cost, Q-switched devices have become available. Although considerably less expensive, these units have little to no long-term track records and are of unknown quality. Choosing a device with a more established company is recommended.

Contraindications ⁸

• Ink allergy.

Also see Chapter 26, Hair Reduction with Lasers, for additional laser contraindications.

Advantages of Laser Tattoo Removal

• Considered the “gold standard” for tattoo removal.

• Individual treatments are relatively quick.

• Provides the best cosmetic result when compared to other forms of tattoo removal.

Disadvantages of Laser Tattoo Removal

• Expensive.

• Painful.

• Multiple treatments are required.

• The procedure has risks of hyperpigmentation, hypopigmentation, depigmentation, and textural changes.

Equipment

• Q-Switched laser device

• Topical anesthetic

• Tongue depressors to apply anesthetic

• Gauze pads to remove anesthetic

• Sterile wipes or alcohol wipes to cleanse the treatment area

• Protective eyewear for patient and laser operator and any other personnel in the room

• Appropriate door sign indicating laser usage

• Ice packs

• Nonsterile gloves

• Face shield for laser operator (optional)

• Masks for laser operator (optional).

Although relatively reliable, Q-switched lasers, like any laser device, are made of sensitive components. Q-switched lasers should not be transported from location to location and all measures should be taken to move the device as little as possible. To ensure that calibration and mirror alignment within the laser arm are adequate, one can aim the laser on a wooden tongue depressor and observe the formation of concentric circles with a laser pulse. If this pattern does not appear, the equipment is due for a calibration. When not in use, the foot pedal should be properly stored and the key removed. Always take care to not damage the laser arm.

Q-switched lasers can rupture blood vessels and aerosolize tissue, so a laser operator may choose to use a plastic shield or a cone device on the laser tip to protect from tissue and blood contact as well as a face shield and mask.

Procedure Preparation

1. Review the patient’s medical history to ensure there are no contraindications to treatment (see Contraindication section). If there is a history of herpes simplex in or near the treatment area, prophylactic antiviral medication is used 2 days prior and 3 days after the treatment. If the risk of herpes is low, antivirals may instead be started on the day of treatment.

2. Review the tattoo history: amateur/professional/cosmetic/traumatic, years present, flesh-colored or white ink, “cover-up” tattoo, previous methods used for removal and scarring at the tattoo site.

3. Determine the patient’s Fitzpatrick skin type (see Chapter 19, Aesthetic Principles and Consultation).

4. Perform a brief and focused physical examination to rule out ink allergy. Ink allergy presents with signs of an allergic contact dermatitis (erythema, edema, induration, and discomfort in previously tattooed areas). A severe red ink dermatitis is shown in Figure 30-5. Examine the tattoo carefully for areas of scarring; document if present and inform the patient.

5. Photograph the tattoo.

FIGURE 30-5 Red tattoo ink dermatitis, prior to laser treatment.

(Courtesy of W. Kirby, MD.)

Laser Tattoo Removal: Steps and Principles

The following guidelines are based on treatment of artistic tattoos using a Q-switched laser (HOYA ConBio RevLite), which is indicated for all Fitzpatrick skin types (I through VI). Manufacturer guidelines specific to the device used should be followed at the time of treatment.

General Treatment Technique

1. The appropriate wavelength is selected for the tattoo ink color to be treated. Colored inks are often a mixture of different colors and it is safest to use a 1064 nm wavelength for initial treatments of multicolored tattoos.

• Treatment 1: Use a 1064 nm wavelength regardless of the color of the tattoo.

• Treatments 2 through 4: Use a 1064 nm wavelength for multicolored tattoos in the dark areas (black, blue, purple, green), and a 532 nm wavelength for red-colored ink areas.

• Treatments 5 and greater: Treat the whole tattoo with a 1064 nm wavelength first and then treat specific colored areas with the wavelength appropriate for the color. For example, the fifth treatment for a green tattoo with red and sky blue ink would be as follows: 1064 nm to the whole tattoo, followed by 650 nm to the whole tattoo, 532 nm to the red areas, and 585 nm to the sky blue areas.

2. Start with larger spot sizes (e.g., 6 to 8 mm) for initial treatments and progress to smaller spot sizes (e.g., 4 mm) over the treatment series. Larger spots penetrate deeper and are less aggressive with fewer side effects.

3. The laser tip is moved smoothly in a painting motion over the tattoo and is not in direct contact with the skin.

4. Universal precautions should be used during and after the treatment due to possible tissue splatter and bleeding.

Planning and Designing

Treatment of thinner skinned areas such as the neck, breast, and below the knees can result in adverse reactions, so conservative settings with lower fluences and larger spot sizes are advised.

For large tattoos covering an entire extremity, consider performing the dorsal area in one session and volar area in a subsequent session to avoid circumferential edema and a possible tourniqueting effect.

“Cover-up” tattoos, in which a second tattoo has been placed on top of the initial tattoo, have a greater density of ink and should be treated with very low fluences initially to reduce the risk of overtreatment.

Anesthesia

Tattoo treatments are painful but can be performed relatively quickly. Some patients may forgo anesthesia altogether, but many patients require some form of local anesthesia. A topical anesthetic cream such as benzocaine:lidocaine:tetracaine (see the Resources list at the end of the chapter) may be used under occlusion with plastic wrap for 30 minutes in the office prior to the laser treatment. If complete anesthesia is desired, injections of 1% or 2% lidocaine with epinephrine subdermally may be used. Local injection is discouraged by the authors because clinical experience has shown increased bleeding and edema at the time of treatment, rendering treatments less effective.

Performing the Procedure

1. Remove any reflective jewelry that may scatter laser light.

2. Apply topical anesthetic (such as benzocaine:lidocaine:tetracaine) in the office and remove after 30 minutes of contact time.

TIP: Patients will experience discomfort in spite of analgesic measures used, and reminding patients to breathe during treatments will assist with pain management. Squeezing the treated area is also a useful distraction technique.

3. Position the patient on the treatment table in a comfortable position allowing for exposure of the tattoo.

4. Cleanse the treatment area with a sterile wipe or alcohol and allow to dry.

5. Provide wavelength-specific protective eyewear to all people in the room. If working on the face, provide the patient with lead extraocular goggles.

6. The laser operator should be positioned comfortably, often sitting, as opposed to leaning over the patient. This will allow for comfortable manipulation of the headpiece while depressing the foot pedal that is used with most laser systems.

7. The wheels on the device should be placed in the locked position to ensure that the unit does not roll during treatment.

8. Select the appropriate wavelength for the tattoo color (see the General Treatment Technique section earlier in this chapter).

9. Select the appropriate spot size based on the patient’s Fitzpatrick skin type using the manufacturer’s guidelines. In general, for initial treatments, larger spot sizes (e.g., 8 mm) should be selected for darker Fitzpatrick skin types (V and VI) and smaller spot sizes (6 mm) for lighter skin types (I through III).

10. Confirm again that everyone in the room is wearing appropriate eyewear at all times and all doors are fully closed.

11. Hold the handpiece at a 90-degree angle to the skin.

12. Instruct the patient not to move if he or she experiences discomfort and, to inform you if a short rest is needed during the treatment.

13. Perform a test spot on the darkest area of the tattoo using the 1064 nm wavelength (regardless of the tattoo ink color) and observe for clinical endpoints. The amount of ink present is highly variable and settings will be determined by the tissue response to the test spot performed. Desirable clinical endpoints include:

• Whitening of the tattoo ink. Figure 30-6 shows whitening of a black ink tattoo using a 1064 nm Q-switched laser (HOYA ConBio RevLite).

• Audible and palpable snapping felt during laser pulses due to photoacoustic vibration.

• Edema.

• Petechiae are desirable endpoints and indicate aggressive settings. This is more commonly seen with shorter wavelengths, such as 532 nm.

TIP: If the tattoo ink appears yellowish or brown immediately after the laser pulse, increase the fluence to obtain a white spot.

TIP: Dark tattoos with high concentrations of ink will require lower starting fluences and larger spot sizes than lighter faded tattoos.

14. Pinpoint bleeding results from vascular injury and represents an overly aggressive treatment. The fluence should be reduced if this occurs. Some of the newer tattoo laser technologies available have modified beam profiles, which have reduced the occurrence of pinpoint bleeding.

15. The initial treatment session may be performed with conservative settings and minimal endpoints to determine how a patient will respond, particularly with darker skin types and very dark tattoos.

16. At subsequent visits the tattoo ink will lighten and the fluence should be increased or spot size reduced for more aggressive treatments to achieve desired endpoints. Typically, the fluence is increased first, based on the manufacturer’s recommended treatment parameters. After maximizing the fluence over several visits, the spot size is then decreased with an associated reduction in fluence.

TIP: A test spot should be performed at each visit prior to initiating treatment to determine the appropriate settings.

CAUTION: Watch for vasovagal signs of light-headedness, perspiration, and fatigue and discontinue treatment if these occur.

FIGURE 30-6 Laser tattoo removal treatment showing immediate clinical endpoint of whitening.

(Copyright Rebecca Small, MD, using HOYA ConBio RevLite™.)

Results

Immediately after a Q-switched laser treatment, the tattoo will have a white discoloration. Figure 30-6 shows a blue-black tattoo during treatment with immediate whitening. This white color change is thought to be the result of rapid, heat-formed steam, causing dermal and epidermal vacuolization. Patients may perceive this as reduction of ink, but this positive change is only temporary and typically lasts for 20 minutes or less. Ink color will gradually fade during the month following each treatment. Results from laser treatments for removal of tattoo ink are cumulative and results from some treatments will be more noticeable than others.

Figure 30-7 shows a blue-black professional tattoo (A) before and (B) after five treatments with a Q-switched laser using 1064 nm wavelength (HOYA ConBio Medlite) demonstrating typical tattoo clearance. Figure 30-8 shows a multicolor professional tattoo (A) before, (B) midway through treatment with lightening of the black ink and hypopigmentation, and (C) after completion of treatment with a Q-switched laser using 1064, 532, and 585 nm wavelengths for black/blue, red/yellow, and sky blue inks, respectively (HOYA ConBio Medlite).

FIGURE 30-7 A blue-black professional tattoo (A) prior to and (B) after completion of five treatments with a Q-switched laser using a 1064 nm wavelength.

(Courtesy of W. Kirby, MD, using HOYA ConBio Medlite™.)

FIGURE 30-8 A multicolor professional tattoo (A) before, (B) midway through treatment with lightening of the black ink and mild hypopigmentation, and (C) after completion of treatment showing resolution of hypopigmentation with a Q-switched laser using 1064, 532, and 585 nm wavelengths for black/blue, red/yellow, and sky blue inks, respectively.

(Courtesy of R. Anderson, MD, and S. Kilmer, MD, using HOYA ConBio Medlite™.)

Occasionally colored inks may darken with treatment due to darker constituent inks. Figure 30-9A shows a red ink tattoo prior to treatment. This tattoo was initially treated with a Q-switched laser using a 1064 nm wavelength (Medlite, Hoya ConBio) and the tattoo ink darkened and became black in color (Figure 30-9B). Subsequent treatments were performed using a 1064 nm wavelength for black and a 532 nm wavelength for red ink areas.

FIGURE 30-9 Red tattoo ink (A) prior to and (B) after treatment with a Q-switched laser using a 1064 nm wavelength demonstrating paradoxical darkening.

(Courtesy of W. Kirby, MD, using HOYA ConBio Medlite™.)

Aftercare

Laser tattoo removal treatment normally results in temporary swelling, redness, and tenderness of the treated area, which may take a few hours to resolve. Ice is applied immediately after treatment for patient comfort and for 15 minutes every 1 to 2 hours on the day of treatment to reduce the risk of blistering.

If the treated skin is fully intact and in an area that will not be abraded, a broad-spectrum sunscreen (containing zinc or titanium) with an SPF of 30 or greater can be applied without a dressing. If the skin is not intact, an occlusive ointment, like Aquaphor, should be applied and loosely covered with a nonadherent dressing and tape that is changed once daily, for moist wound healing. Care should be taken not to macerate the treated area with excessive occlusion. Once the skin is intact, a daily broad-spectrum sunscreen should be applied for the duration of the tattoo removal treatments.

A crust may appear over the treated area that sloughs off at approximately 14 days post-treatment. The treated skin appears slightly shiny until the area has fully healed. Crusts or blisters should not be removed and patients cautioned against picking, which increases the risk of scarring. Mild pruritus is part of the healing process and is common during the first few weeks following treatment.

Strenuous exercise and exposure to water should be avoided until the skin is intact. Elevation of treated extremities can reduce edema.

Follow-Up

A 6 to 8 week interval between treatments is necessary to allow the skin to heal completely. This interval may be extended without any reduction in efficacy and, in fact, treated tattoo ink may continue to fade slightly over time. The tattoo is appropriate for retreatment once the skin is fully intact, without a crust and the shiny appearance to the skin has resolved. Patients often request more frequent treatment sessions as they are usually highly motivated to remove their tattoos. However, treating too frequently, such as every 4 weeks, may increase the chances of textural changes, scarring, and hypopigmentation.

Complications

• Hyperpigmentation

• Hypopigmentation/depigmentation

• Blistering

• Bleeding

• Textural changes

• Scarring (including hypertrophic and keloids)

• Prolonged healing

• Infection (e.g., herpes simplex, varicella zoster)

• Paradoxical tattoo darkening (flesh-colored ink or permanent makeup)

• Allergic reactions with local dermatitis/nodules or systemic allergic response (rare).

A fine line exists between expected side effects and true complications from laser tattoo removal treatments. For example, discomfort, swelling, blistering, and itching are commonly associated with the treatment ⁸ but extreme pain, limb edema, bulla, and intractable pruritus are rare and indicate treatment complications.

About half of the patients treated with Q-switched lasers for tattoo removal will show some transient changes in the normal skin pigmentation (hyperpigmentation or hypopigmentation).^5,⁹ These changes usually resolve in 6 to 12 months but rarely may be permanent.^7,¹⁰ The risk of hyperpigmentation and hypopigmentation is greatest with skin types IV, V, and VI, regardless of the wavelength used. Areas that blister and bleed are more likely to have pigmentary and textural changes.¹¹ Twice daily treatment with hydroquinone and broad-spectrum sunscreens on fully healed skin usually resolve hyperpigmentation within a few months, although in some patients resolution can be prolonged. Shorter wavelengths, such as 532 nm, are more commonly associated with blistering and hypopigmentation than longer wavelengths.

Transient textural changes are common and typically resolve within a few months; however, permanent textural changes and scarring can occur.¹⁰ If a patient is prone to pigmentary or textural changes, longer treatment intervals are recommended. Additionally, patients with a history of hypertrophic scarring need to be warned of their increased risk of scarring.

Local allergic responses to tattoo pigments have been reported at the time of tattoo placement, and allergic reactions to tattoo pigment can also occur after Q-switched laser treatment.¹³^–¹⁸ For example, photoallergic reactions have been reported to yellow cadmium sulfide, a pigment commonly added to tattoos to brighten red or yellow inks. This reaction is also reported with red ink, which may contain cinnabar (mercuric sulfide), green (chromium), and blue (cobalt).^21,²² Erythema, pruritus, and even inflamed nodules, verrucose papules, or granulomas may occur. The reaction is confined to the site of the red/yellow ink. Treatment consists of strict sunlight avoidance, use of sunscreen, intralesional steroid injections, or in some cases, surgical removal.²² Q-switched lasers mobilize the ink through the lymphatic system and systemic allergic responses are extremely rare complications. Oral antihistamines and anti-inflammatory steroids may also be used to treat allergic reactions to tattoo ink.²³

Treating Specific Lesions

Caution should be used with cosmetic ink appearing pink, flesh colored, or peach because these may contain iron oxide or titanium oxide pigments.²⁵ These pigments, when treated with a Q-switched laser, may turn brown or black in a phenomenon known as paradoxical darkening.⁹ Although this brown or black color usually responds well to continued treatment, it can be disconcerting to patients as the effect of early treatment will often leave the tattoo looking darker than it did prior to treatment. If tattoo darkening does occur, after 8 weeks, the newly darkened tattoo can be treated as if it were black pigment with 1064 nm.

One of the newest forms of tattoo ink is an iridescent pigment that is only observable under a black light. Patients refer to these tattoos as “glow-in-the-dark.” These patients should not be treated because their ink contains no chromophore for selective absorption.

Occasionally patients will present with tattoos that are slightly raised. Prior to laser treatment, if a tattoo is palpable, it will still be palpable when the treatment series is completed. It is important to remember that Q-switched lasers only treat ectopic pigment and are not intended to improve the texture of the skin.

Traumatic tattoos resulting from asphalt or “road rash” can be effectively treated with laser tattoo removal methods.²⁴ Obtaining a proper history is imperative when treating any traumatic tattoo because case reports of laser ignition from flammable debris have been reported.^12,²⁶