Lesion selection

Just as important as patient selection is evaluation of the lesion itself. Tattoos can be divided into amateur, professional, cosmetic, medical, and traumatic categories. In amateur tattoos, a steel needle is used to deposit ink, which may be at various depths of the skin, whereas in professional tattoos, a hollow needle is used to inject ink into the dermal layer of skin. Amateur tattoos typically contain pigment of unknown sources such as ash, coal, or India ink (Fig. 3.1). On the other hand, professional tattoo artists often combine ink pigments to achieve novel colors and shading. Cosmetic tattoos using skin-colored tones are important to distinguish, as are medical tattoos such as those used as radiation markers. For traumatic tattoos, it is important to understand the nature of the injury that caused it so as to be aware of the type of material implanted in the skin prior to treatment.

Figure 3.1 Amateur tattoo placed on the hand in a person with Fitzpatrick skin phototype IV.

It is critical when treating pigmented lesions other than tattoos that the lesion itself be evaluated for malignancy. Lasers should not be used for any kind of melanoma, as even with in situ melanoma recurrence rates are very high. Similarly, we recommend against the removal of dysplastic nevi with lasers even though studies have shown no significant increase in carcinogenic markers after laser stimulation of melanocytes.

Patient selection in general

At initial consultation for removal of a pigmented lesion, it is important to take a thorough medical history including a history of allergy to anesthetics (both topical and injectable), current medical conditions, and medications. If a patient is currently taking isotretinoin, laser treatment should be delayed until medication completion as, theoretically, there is a potential for increased scarring and delayed healing. In addition, it is important to note if the patient was ever treated with systemic gold therapy (e.g. rheumatoid arthritis therapy) as this is an absolute contraindication to QS laser treatment since darkening of gold-containing skin is immediate and irreversible. Prophylaxis is appropriate in patients with a history of herpes simplex virus if treating near the trigger point. A history of keloidal scarring and a tendency toward postinflammatory hypo- or hyperpigmentation should also be documented.

Patient selection for tattoo removal

Though tattoos are increasingly popular, they often become a source of personal regret as up to 50% of adults older than 40 with tattoos seek their removal. It is critical that a thorough history of the tattoo be taken prior to deciding upon a treatment plan to establish appropriate patient expectations (Box 3.1). Kirby et al recently published a scale to help practitioners estimate the number of treatment sessions needed for tattoo removal to appropriately guide patients who often enter the laser removal process of their tattoos with uncertainty and misconceptions (Table 3.1). In the scale, numerical values are assigned to six parameters: (1) Fitzpatrick skin phototype, (2) location, (3) color, (4) amount of ink used in the tattoo, (5) scarring or tissue change, and (6) ink layering. The points for each parameter are combined, which results in the approximate number of treatment sessions needed to successfully remove the tattoo, plus or minus 2.5.

In addition to setting a realistic number of treatment sessions for the patient, it is important to alert the patient that some tattoo pigment may still remain and that hypopigmentation may occur in the area, which will leave the outline of the tattoo sans ink. This is especially true in patients with Fitzpatrick skin phototypes IV–VI or in patients with a tan.

The ideal patient for tattoo removal is an untanned patient with type I or II skin and a dark-blue or black tattoo that has been present for at least a year. The older the tattoo, the better is the response to laser treatment as macrophages are already present in the skin and have been at work trying to actively phagocytose the foreign pigment particles. This natural attempt by the body to remove the foreign tattoo ink pigment is the reason why older tattoos are often illegible and have blurry or indistinct margins. Multicolored tattoos, regardless of background skin color, can be very difficult to remove completely with traditional laser systems and treatment should be performed only after the patient fully understands the potential for incomplete fading, pigmentary alterations or scarring. Treatment sessions should be spaced at least 6–8 weeks apart.

Patient selection for benign pigmented lesion removal

As with tattoo removal, it is important to assess the patient presenting for benign lesion removal (Box 3.2). The greater the contrast between background skin and pigmented lesion, the more likely the laser surgeon is to achieve success. At preliminary evaluation, a Wood’s lamp examination may be helpful to assess depth of pigment. Understanding whether the lesion is epidermal, present at the dermoepidermal junction, or dermal will guide laser selection and also allow the physician to set realistic expectations for removal.

Patients should not be tanned when treated and it is important to stress that regular sunscreen use will aid in a durable result (especially in the case of solar lentigines). In patients with darker skin types, we recommend pre-treating pigmented areas with hydroquinone 4% and ceasing treatment 1 week prior to laser therapy. Post-therapy we recommend the use of low potency-topical corticosteroids for 3–4 days to prevent any pigment alteration due to inflammation from the treatment itself. Compared with patients with Fitzpatrick skin phototypes I–III, those with skin photoypes IV–VI have a higher risk of pigmentary alteration and scarring.

Lentigines can be treated most reliably, whereas postinflammatory hyperpigmentation (PIH) and nevi of Ota and Ito present more of a challenge.

Patient preparation

The area to be treated should always be free of any topicals. Removal of pigmented lesions and tattoos can be quite painful for the patient, especially if a large area is to be treated. On the face, we recommend topical anesthetic mixtures that can be compounded at the pharmacy consisting of betacaine, lidocaine, and tetracaine (a typical concentration is 7% of each), or the patient can use a commercial preparation such as LMX-4 or EMLA. A thick layer of this mixture is spread evenly over the treatment area with anesthesia taking place usually within 45 minutes. Penetration of the topical anesthetic can be enhanced by putting the medication under occlusion or applying warm towels over the area. Caution should be exercised if the area is large as topical anesthetics can produce toxicity. Anesthetic should always be completely removed prior to treatment.

Ice is another option, though we recommend ice cubes wrapped in frozen gauze rather than ice packs as the latter tend to not maintain an even temperature. The ice should precede the laser treatment with caution to ensure that no water is left behind. For dermal pigmented lesions on the face, such as nevus of Ota, we sometimes will anesthetize the area with 1% lidocaine.

After informed consent is obtained, pre-treatment photographs are taken. As with any medical procedure, universal precautions should be followed. All QS lasers employ a cone or cylinder placed between the handpiece and the skin to catch any skin debris ejected during laser treatment. Because the cones contain fragments of skin, it is important to use gloves when removing them from the laser after treatment.

Eye safety is also paramount when using lasers. Wavelength-specific protective glasses or goggles must be worn by the patient, provider, and staff at all times during a laser procedure. If the area to be treated is on the eyelid or near the orbit, in the case of the deeply penetrating Nd : YAG 1064 nm laser, internal metal eye shields should be placed for the patient.

In general

Prior to commencing full treatment in darkly pigmented individuals, it is advisable to perform test spots on pigmented lesions or tattoos. Test spots should be evaluated at 4–6 weeks for hypo- or hyperpigmentation and efficacy. When using a QS laser, the initial desired response for epidermal and dermoepidermal pigmented lesions is immediate lesion whitening or graying, which represents cavitation. This may be more difficult to gauge if using an IPL system in which the primary endpoint in pigmented lesions is subtle darkening (see Ch. 5). Within 20–30 minutes, this gray converts to erythema. In dermal lesions, the immediate whitening is less vivid.

A snapping sound is common with QS laser use as pigment particles and the cells that contain melanin or tattoo particles are heated and explode. The lesion is fully covered with laser pulses. The immediate whitening keeps additional light from entering the skin due to reflection. Pulse stacking should be avoided as this may increase the risk of scarring and unnecessary thermal injury. If significant energy is absorbed by a pigmented lesion, pinpoint bleeding may occur, as occasionally occurs with tattoos. Performing 2–4 treatments of a tattoo all in one day (waiting for the immediate whitening to fade between treatments) seems to increase the degree of fading achieved in one visit.

Case Study 1

Uneven tissue response in a black tattoo

AR is a 39-year-old man with an amateur tattoo on the hand. The tattoo appears black and the patient reports that his ‘friend put it there’. The patient does not have a tan. After icing the area for 15 minutes, the tattoo is treated with the QS Nd : YAG laser at a fluence of 3.0 J/cm². The tattoo responds immediately and turns white and then erythematous. Unlike the rest of the tattoo, the central portion develops an erosion immediately upon treatment. This occurred because, in amateur tattoos, pigment is not placed at a uniform depth or in a uniform concentration. The tattoo was treated from the periphery to the center. While the periphery responded well, it was too much energy for the center, which led to immediate epidermal sloughing and pinpoint bleeding (Figs 3.1 and 3.2).

Figure 3.2 Amateur tattoo immediately after treatment with the QS Nd : YAG laser showing punctuate bleeding.

Patients and equipment for dark-blue or black tattoo treatment

Fitzpatrick skin phototypes I–III

In lighter-skinned patients (in the absence of a tan or bronzer), the practitioner has several options (Table 3.2). The QS alexandrite (755 nm), the QS ruby (694 nm), and the QS Nd : YAG (1064 nm) lasers are all effective for dark-blue and black tattoos (Fig. 3.3). In the case of traumatic tattoos that appear black, it is important to know the origin of the trauma since such tattoos may react with a small explosion (e.g. gun powder tattoo) after laser treatment.

Table 3.2 Laser choices based on tattoo ink color

Figure 3.3 Black amateur tattoo on the arm seen (A) preoperatively, and (B) 6 weeks later following a single treatment with the Q-switched ruby laser with only small speckles of ink remaining.

Patients and equipment for red tattoo treatment

The optimal laser wavelength for removing red tattoo ink is 532 nm (QS frequency-doubled Nd : YAG). This wavelength can cause both hyperpigmentation and hypopigmentation in darker-skinned patients so treatment should be limited to phototype I–III patients. It should be noted that red tattoo ink is often the culprit for allergic reactions after tattoo placement and granulomatous reactions in the tattoo itself (Fig. 3.4). Laser removal of the red ink can cause greater dispersion of the antigen resulting in urticaria or a systemic allergic reaction. In these cases, an ablative CO₂ or Er : YAG laser can be employed to vaporize the tattoo (Fig. 3.5). If a QS-laser is employed, the patient should be covered with systemic corticosteroids and antihistamines and the laser surgeon should proceed with caution (Case study 2).

Figure 3.4 Multicolored tattoo showed allergy to yellow ink. The area was successfully treated with Class I topical corticosteroids thus avoiding the need to remove the tattoos with laser.

Figure 3.5 Tattoo granulomas from an allergic reaction to the red (cinnabar or mercury tattoo ink) color in a multicolored tattoo seen (A) preoperatively, (B) immediately after removal of the tattoo and all granulomas with the vaporizational mode of the carbon dioxide laser, and (C) 3 months later showing the residual erythematous permanent scar.

Case Study 2

When laser removal is not an option

TV is a 53-year-old woman who decided to have a red daisy on a green stem placed on her ankle 1 year ago. Approximately 3 months after getting the tattoo, she complained of itching in the area and noticed a gradual thickening of the skin. She had not experienced this with her other tattoos and has one on the dorsal foot of the same lower extremity that was normal in appearance. She tried clobetasol cream to the area, which initially helped and then failed and then she used flurandrenolide (Cordran®) tape, which worked to alleviate the itch but not the size of the reaction in the area. On exam, the patient is skin phototype V with a thick plaque on the ankle in which one can begin to make out individual flower petals. No visible red ink remained but the green stem was still present. Given her background skin tone and history of red ink, the decision was made to forgo laser therapy of the area in favor of surgical excision. The pathology showed a pseudolymphoma resulting from a granulomatous reaction to the red ink. In this case, QS laser therapy would have been of minimal benefit and surgical therapy became the mainstay of treatment (Fig. 3.6).

Figure 3.6 Biopsy proven pseudolymphoma in the portions of the tattoo decorated with red ink.

Patients and equipment for green tattoo treatment

The optimal laser wavelength for removing green tattoo ink is the QS ruby laser (694 nm). Because this wavelength is well absorbed by melanin, caution should be used, as injury to melanocytes can lead to transient hypopigmentation and even permanent depigmentation as well as textural change. The goal of treatment should be immediate tissue whitening with minimal or no bleeding.

Patients and equipment for epidermal lesions

Solar lentigines, lentigo simplex, and ephelides

Pigment that is in the epidermis accounts for lesions such as solar lentigines, lentigo simplex, and ephelides. Any laser system that damages the epidermis will therefore result in improvement in 1–2 treatment sessions (Fig. 3.7). Conversely, if the epidermal damage is part of a deeper destruction, there may be scarring or dyspigmentation afterward. Fractional photothermolysis can be considered for these conditions especially if the lesions are widespread (see Ch. 6), but the mainstay lasers are the QS alexandrite, QS Nd : YAG (532 nm), and QS ruby lasers. Long-pulsed lasers and IPL can also be effective (see Ch. 5).

Figure 3.7 Multiple small brown lentigines on the back of the hand seen (A) preoperatively, and (B) with nearly complete resolution 6 weeks after a single treatment with the Q-switched Nd : YAG laser.

Pearl 5

After treatment of solar lentigines or ephelides it is important for the patient to practice regular, diligent sun protection to prevent recurrence of pigment. Mineral sunscreens are preferable as they provide a physical block to ultraviolet rays. Even if the patient reports minimal outdoor exposure, the physician should remind the patient that even driving can cause repigmentation since windshield glass does not filter UVA light.

Labial melanotic macules

Melanotic macules on the lip vermilion are a feature of several entities including physiological racial pigmentation, Laugier-Hunziker syndrome, and Peutz-Jeghers syndrome. These can be treated using the QS ruby or QS alexandrite or frequency-doubled QS Nd : YAG lasers. In the case of the syndromes, patients should be made aware that new macules will develop over time (Fig. 3.8).

Figure 3.8 Multiple small lentigines of the oral mucosa seen with Peutz-Jeghers syndrome seen (A) preoperatively, and (B) 6 weeks after three treatments with the Q-switched ruby laser showing excellent fading without scarring.

Pearl 6

A mental nerve block using 0.3–0.5 mL of lidocaine provides adequate anesthesia for treatment of labial melanotic macules on the lower lip while an infraorbital nerve block provides anesthesia for the upper lip. Both can be achieved quickly via an intraoral approach. For the upper lip, inject between the first and second premolars angling the needle upwards towards the mid-pupillary line. For the lower lip, inject between the first and second lower premolars.

Café au lait macules and nevus spilus

Café-au-lait macules (‘CALM’) vary in color, size, and shape but histologically the excess pigment is found at the basal layer. When darker macules exist with the CALM, it is referred to as a nevus spilus. Before treating CALMS, one should always take a careful history to rule out neurofibromatosis (if multiple macules exist). Lasers that are usually used to treat these lesions include the QS Nd : YAG, QS ruby, and QS alexandrite lasers. Patients with darker skin are at risk for hyperpigmentation and hypopigmentation. Light-skinned patients are the ideal candidates for CALM removal, but recurrences, residual hyperpigmentation, and incomplete pigment removal are common. Treatment sessions are spaced at least 8 weeks apart and clearance requires at least 2–4 treatment sessions (Fig. 3.9).

Figure 3.9 Solitary café au lait patch on the leg showing the complication of hyperpigmentation of the lateral portion of the lesion 12 weeks after testing with the Q-switched Nd : YAG laser.

Patients and equipment for dermoepidermal lesions

Lesions in this category include Becker’s nevus, melasma, postinflammatory hyperpigmentation, drug-induced hyperpigmentation, and nevocellular nevi. Pigment is present at the dermoepidermal junction and, in the case of a Becker’s nevus, in addition to the pigment there are often terminal hairs in the lesion itself. Nevocellular, junctional, and compound melanocytic nevi should be treated with laser only if the operator is certain that they are benign.

Postinflammatory hyperpigmentation

PIH occurs due to hemosiderin and / or melanin deposition. Because this condition arises due to inflammation, it is important to use low fluences and ensure that the patient does not develop significant post-treatment erythema to provoke additional PIH. For this reason, test spots are encouraged prior to treating large areas. The laser system currently used most often for PIH is the fractional photothermolysis system, even though treatment with this laser has been reported to induce PIH itself (see Ch. 6). PIH can occur on the face, but can also be a result of hemosiderin deposition after sclerotherapy. For post-sclerotherapy hyperpigmentation, the QS ruby or IPL (see Ch. 5) can be used (Fig. 3.10). All patients being treated for PIH on the face should use topical hydroquinone 4% cream along with a broad-spectrum sunscreen before and after treatment. Before using a laser for facial PIH, we recommend a trial of topical retinoids and a series of chemical peels to try to improve the discoloration with laser as the final step. Recurrence is frequently seen, especially after sun exposure.

Figure 3.10 Area of postinflammatory hyperpigmentation following sclerotherapy for small leg veins seen (A) preoperatively, and (B) 6 weeks after multiple treatments with the Q-switched ruby laser.

Pearl 7

Controversy exists regarding the long-term use of hydroquinone. Although it is reasonable to offer patients peels, there are over-the-counter preparations that are hydroquinone free if the patient wishes to maintain their post-laser results. Ingredients in these hydroquinone-free products include compounds such as kojic acid, anisic acid, and arbutin.

Patients and equipment for dermal lesions

Dermal lesions have pigment deeper in the dermis that require devices with longer wavelengths. Examples of such lesions include nevi of Ota, Ito, and Hori, and congenital dermal melanocytosis also known as Mongolian spots. Argyria is an additional example of a dermal process that manifests as a result of ingestion of silver and can be treated with QS laser.

Nevi of Ota, Ito, and Hori

Nevus of Ota presents on the face as a blue-black, brown, or gray patch that develops after birth or in adolescence with a unilateral distribution that may involve the sclera. Nevus of Ito is similar, but its location is usually on the shoulder. Hori’s nevus is typically bilateral and located in the malar region. In darker-skinned (type IV–VI) patients, the QS Nd : YAG laser at 1064 nm is usually the safest laser to lighten a nevus of Ota, Ito or Hori. In lighter-skinned patients, QS ruby laser at 694 nm and QS alexandrite laser at 755 nm can also be used (Fig. 3.11). Recently, a fractionated 1440 nm Nd : YAG laser has been reported to clear nevus of Ota. Treatments are usually spaced 3–4 months apart with up to 10 treatment sessions needed for clearance with QS lasers, and 2–3 treatment sessions with the fractionated laser. Nevus of Ota patients should be made aware that the sclera component of the lesion is not amenable to treatment with current technology.

Figure 3.11 Small nevus of Ota is seen: (A) preoperatively, (B) 6 weeks after two treatments with the Q-switched ruby laser showing some fading, and (C) with nearly complete fading 6 weeks after the fourth treatment.

Troubleshooting for tattoo removal

When evaluating a tattoo patient prior to initiating therapy, carefully palpate and examine the site to be sure that no pre-existing scarring, hypopigmentation, or induration is present. Many patients may not realize that the actual tattooing procedure can cause both scars and loss of normal pigmentation.

Incomplete removal of the tattoo is a common problem following laser treatment. If treatment is ineffective, an increase in energy fluence may be necessary, but care must always be taken to stay within safe treatment parameters to avoid scarring or pigmentary alterations. In some cases, changing to a different laser may be worthwhile due to the intrinsic differences in wavelengths, pulse durations, and spot sizes.

Troubleshooting for pigmented lesion removal

As with tattoos, incomplete removal of benign pigmented lesions following laser treatment is the chief problem. However, unlike tattoos, only a few additional treatments will usually lead to total or near-total removal of CALMs, lentigines, and nevi of Ota and Ito. Increasing the energy fluence often produces improvement in resistant lesions. When treating lentigines, if the patient has lesions on both their hands and face, it is always best to treat the hand lesions first so that if an untoward reaction results it will result in less patient unhappiness than if the same problem had developed on the face. This is especially true in patients with darker skin types. However, the face heals much faster and tends to be more forgiving than the hands.

Side effects and complications

Special situations