Cosmetic Tattoos

 

Treatment of cosmetic tattoos is challenging. Cosmetic tattoos are traditionally treated by Q-switched lasers but it is very difficult to have satisfactory results. Although Q-switched lasers are very effective for removing black tattoos, some cosmetic tattoos are difficult to treat and can even develop a paradoxical color shift due to reduction of the metallic component in the inks. Physicians should be very careful when dealing with tattoo inks other than black color.

 

White ink contains white titanium dioxide, and brown ink contains ferric oxide. These pigments turn dark by a reduction reaction upon laser excitation. Dr. Fur-Jiang Leu et al. studied on the Effects of tattoo ink’s absorption spectra and particle size on cosmetic tattoo treatment efficacy using Q-switched Nd-YAG laser (532 nm, 3-mm spot size, 2.5 J/cm2; 1,064 nm, 3-mm spot size, 6.5 J/cm2) two sessions in a 1-month interval.

 

They found black tattoo ink’s excellent response to Q-switched lasers was associated with its strong absorption and small particle size. In contrast, white tattoo ink’s poor response was associated with its poor absorption, even after laser darkening, and large particle size.

 

Since the introduction of fractional laser, its most application was for depressed acne scar in Taiwan. Because of the difficulties in removing cosmetic non-black colored tattoos, Dr. Chia-Chen Wang et al. studies the effect of a 1,550 nm, erbium-glass fractional laser system with energy settings of 17 mJ and 169 MTZ/cm2, 2 passes (total density of 338 MTZ/cm2) for five sessions at 1-month intervals on rats.

 

They found this non-ablative fractional laser successfully removed white and flesh-colored cosmetic tattoos by transepidermal elimination of tattoo pigments through the disrupted dermal–epidermal junction. In another similar study, they used carbon dioxide (CO2) ablative fractional resurfacing (120 μm spot size, 17.5 mJ, 10% density) to treat white and flesh-colored cosmetic tattoos on rats for five sessions at 1-month intervals.

 

Although CO2 ablative fractional resurfacing is theoretically more effective than non-ablative fractional laser, they found CO2 ablative fractional resurfacing was as effective as non-ablative fractional laser. Through Dr. Wang’s studies, they introduced a novel treatment modality to approach cosmetic tattoos.

 

Spotted Leucoderma

Dr. Chian-Yaw Hwang et al. once reported a rare case of spotted leucoderma after treatment of facial hyperpigmentation on hemodialysis patients employing 1,064 nm Q-switched Nd-YAG laser (6-mm spot size, 3.9 J/cm2, 6 sessions at 8-day intervals). This patient was treated with a significant improvement after three treatment sessions, but spotted leucoderma developed at the fourth visit. Neither residual facial hyperpigmentation nor spotted leucoderma subsequently improved following two additional sessions of 1,064-nm Q-switched Nd-YAG laser at a lower fluence (3.0-3.5 J/cm2) with topical hydroquinone and 12 sessions of low-level energy He-Ne laser.  

 

Treating a melasma or facial hyperpigmentation patient with a high fluence and a too short interval usually results in complications such as spotted hypopigmentation or leucoderma. A fluence of more than 3.0 J/cm2 is regarded as a high fluence in 1,064 nm Q-switched Nd-YAG laser. Thus, the treatment interval should be around 3–4 weeks. The higher the fluence, the longer the treatment interval should be. Also, treatment sessions should be limited if a higher fluence is applied.

 

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Pico Lasers

The new development of pico-second lasers recently brings the treatment of pigment to another brand new field. Initially, it was developed for treatment of cosmetic tattoos in the western countries. Soon, it was used to treat various hyperpigmented lesions in Taiwan. There are currently 4 different picosecond lasers (PicoWay, PicoSure, Pico Q/enlighten, Discovery PICO) on the Taiwan market, each with various specifications and parameters (Table 1). Although very popular indeed, there is still no scientific data on Asian people published yet. It is therefore hard to tell which one is better than the others. It is hoped that the application data and parameters of pico-second lasers for treatment of pigmentation on Asian people will soon be established.

 

Table 1: The different specifications of 4 pico lasers in Taiwan.