Tattoos

Jordan V. Wang

Macrene Alexiades

Nazanin Saedi

BACKGROUND

Tattoo removal using laser devices has gained in popularity, especially as the medical technology continues to advance. According to the American Society for Dermatologic Surgery (ASDS), nearly 70 000 laser, light, and energy-based tattoo removal procedures were performed by members in 2016 alone.¹ With the increased demand by consumers and the availability of several light-based devices in the market, it is crucial for practitioners to be well-versed in laser tattoo removal.

Laser tattoo removal was first performed with argon and CO₂ lasers.² However, they led to significant adverse events because of their nonselective nature. With the advent of devices based on the theory of selective photothermolysis, the concept of targeting specific chromophores with matched wavelengths, the tattoo removal field evolved.³ Application of a wavelength of light that is selectively absorbed by a tattoo pigment causes a rapid rise in temperature leading to a pressure wave that exceeds the tensile strength of the pigment particles and shattering them into smaller fragments. The use of quality-switched (QS) nanosecond lasers subsequently became the standard of care for tattoo removal.² The short pulse durations allow for photoacoustic and photomechanical destruction of pigment without significant collateral thermal damage.

In comparison with other pigments, tattoo pigments have a significantly short thermal relaxation time (TRT), which means that delivering energy in shorter pulse durations—measured in picoseconds—may prove more efficacious.⁴,⁵,⁶ The newest development of picosecond (PS) lasers has now taken advantage of this phenomenon, which has begun to show a trend toward increased effectiveness for tattoo removal.⁷,⁸,⁹ For improved cosmetic outcome and reduction of adverse effects, the approach to tattoo removal should involve the appropriate choice of laser devices and treatment settings.

PRESENTATION

Patients present expressing a desire to remove a tattoo.

In laser tattoo removal, the target chromophore in the skin is the deposited tattoo pigment. In order
to produce different colors, tattoo pigments are composed of unique ingredients¹⁰ (Table 1.3.1). Different pigments preferentially absorb different wavelengths of light. Therefore, the laser of choice should emit a wavelength that is tailored to the targeted pigment. In cases of multicolored tattoos, multiple lasers may be required.

TABLE 1.3.1 Tattoo Pigments and Their Common Ingredients

Tattoo Pigments	Common Ingredients
Black	India ink, ferrous oxide, magnetite, carbon, logwood
Blue	Cobalt aluminum oxide, chromium oxide, copper phthalocyanine
Brown	Iron oxides
Green	Chromium oxide, lead chromate, copper or aluminum phthalocyanine, malachite, ferrocyanides and ferricyanides
Purple	Manganese ammonium pyrophosphate, aluminum salts, quinacridone, dioxazine/carbazole
Red	Mercuric sulfide, cadmium selenide, ferric hydrate, sandalwood, brazilwood, aromatic azo compounds, quinacridone
White	Zinc oxide, titanium dioxide, lead carbonate, barium sulfate
Yellow	Cadmium sulfide, curcuma, chrome yellow

DIAGNOSIS

Clinical Diagnosis

Because of the importance of color, the analysis of tattoo composition is a crucial step in the consultation for laser tattoo removal. Based on the colors in the tattoo, the composition of each pigment may be deduced (see Subtypes section).

Amateur tattoos are often light in color and usually black. Cosmetic tattoos or “permanent makeup” are often found on the eyebrows, eyelid edges, or lip lines and are often a dark brown or gray-black color. However, the inks used often contain reds, browns, and whites made of ferric oxide or titanium dioxide that are resistant to laser treatment or can cause paradoxical darkening. Traumatic tattoos are often jagged and deeply situated, causing a dark blue color and may be composed of carbon. Tattoos are used in medicine to mark radiotherapy sites, and these are usually a dark blue color.

The color of the patient’s skin is also an important consideration, because this can influence adverse effects, such as dyspigmetation. Hypopigmentation and hyperpigmentation are common consequences of any laser treatment. This may prove to be especially untoward for those with darker skin types. If patients have a significant tan, they should be instructed to return after the tan has largely faded. The introduction of the 1064-nm QS Nd:YAG laser has reduced the risk of dyspigmentation compared with other lasers in those with dark skin,¹¹ and it has traditionally been considered the laser of choice for darker skin types. Its picosecond counterpart can also be safely used to treat darkly pigmented tattoos in darker skin types.

For patients with known history of allergic reactions to tattoo pigments, caution should be exercised. Whether previous reactions were considered to be local or systemic, they can potentially reoccur following laser treatment.¹² For moderate to severe cases, laser treatment is not recommended because generalized reactions can ensue. Other modalities, such as surgical excision, should instead be considered in these cases. Practitioners should also be cognizant about the potential for new-onset reactions in patients.¹²,¹³,¹⁴

Histopathology

Histology of tattoo demonstrates aggregated pigment granules within the dermis either extracellularly or phagocytosed in dermal and perivascular macrophages. Overlying fibrosis of the papillary dermis is seen in older tattoos, whereas granulation tissue may be seen in the papillary dermis in newer tattoos. If the tattoo is older, a greater proportion of pigment is found within macrophages than free within the dermis, and there is a decreased amount of total pigment.¹⁵ The size of the pigment particles varies depending on color, with black pigment granules being approximately half the size of red and turquoise pigment particles, but with 99.94% of tattoo particles of six colors measuring under 100 nm in diameter.¹⁶

Subtypes

Table 1.3.1 describes the common ingredients in tattoo pigments.

PATHOGENESIS

Tattoo pigments are deposited into the dermis using sterilized needles dipped in various pigments that repeatedly puncture the skin. The needles are soldered together in groups ranging from 1 to 100 individual needles and in various shape arrangements depending on the intended tattoo technique (eg, outlining vs shading). The needles vary in diameter from 0.2 to 0.4 mm and typically penetrate 1 to 2 mm into the dermis.

TREATMENT

Patient counseling should always be the first step in any laser tattoo removal consultation. Patients should be thoroughly informed and counseled about what the procedure entails, the realistic expectations of outcomes, and the potential for any adverse effects. Multiple treatment sessions are required for maximum improvement, especially for tattoos with larger surface areas, increased depth, and multiple colors. In general, 6 to 10 treatment sessions are considered to be sufficient, but up to 20 sessions may be required in some cases. Potential side effects include local pain, erythema, blistering, bleeding, infection, dyspigmentation, and scarring. Portraying realistic expectations for complete or near-complete tattoo removal is important to maintaining high patient satisfaction. For that reason, no guarantee for complete removal is recommended. It is also suggested that photographs be taken before each treatment session in order to help gauge and better visualize progress. See Algorithm 1.3.1 for lasers employed depending upon color of tattoo ink being treated.

Medical

Medical treatment of tattoos are limited and typically used as adjunctive to laser therapy.

ALGORITHM 1.3.1 Treatment algorithm for tattoos. (Courtesy of Macrene Alexiades, MD, PhD.)

Topical

Imiquimod. Topical application of imiquimod alone has been reported to result in tattoo lightening.¹⁷

Other Agents. Other topical agents that have been reported in years past for tattoo removal include ingredients such as kojic acid, glycolic acid, lactic acid, and trichloroacetic acid.¹⁷ These agents may work by creating a layer of dermal remodeling to overlie and mask the tattoo particles.

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