Q-switched ruby laser irradiation of normal human skin. Histologic and ultrastructural findings.

The Q-switched ruby laser is used for treatment of tatoos. The effects of Q-switched ruby laser pulses on sun-exposed and sun-protected human skin, as well as senile lentigines, were investigated with clinical observation, light microscopy, and transmission electron microscopy. A pinpricklike sensation occurred at radiant exposures as low as 0.2 J/cm2. Immediate erythema, delayed edema, and immediate whitening occurred with increasing radiant exposure. The threshold for immediate whitening varied inversely with skin pigmentation, ranging from a mean of 1.4 J/cm2 in lentigines to 3.1 J/cm2 in sun-protected skin. Transmission electron microscopy showed immediate alteration of mature melanosomes and nuclei within keratinocytes and melanocytes, but stage I and II melanosomes were unaffected. Histologically, immediate injury was confined to the epidermis. There was minimal inflammatory response 1 day after exposure. After 1 week, subthreshold exposures induced hyperpigmentation, with epidermal hyperplasia and increased melanin staining noted histologically. At higher radiant exposures, hypopigmentation occurred with desquamation of a pigmented scale/crust. All sites returned to normal skin color and texture without scarring within 3 to 6 months. These observations suggest that the human skin response to selective photothermolysis of pigmented cells is similar to that reported in animal models, including low radiant exposure stimulation of melanogenesis and high radiant exposure lethal injury to pigmented epidermal cells.     

TREATMENT OF BENIGN PIGMENTED EPIDERMAL LESIONS BY Q-SWITCHED RUBY LASER

Background. Disorders of cutaneous pigmentation are a common problem, which can cause substantial cosmetic morbidity. Traditional treatments are often ineffective and sometimes associated with further hyperpigmentation, hypo-pigmentation, or scarring. Because the Q-switched ruby laser has proven useful for the treatment of tattoos and, in a small number of cases, benign disorders of the epidermal melanin, we decided to apply this modality systematically to additional benign pigmented lesions. Methods. Thirty-four benign pigmented epidermal lesions including lentigines, café-au-lait macules, and nevi spili in nine white patients were exposed to single pulses of a Q-switched ruby laser (694 nm, 40 ns pulse duration) at 4.5 and/or 7.5 J/cm². Results. After one treatment, substantial clearing occurred at each fluence in all lentigines and café-au-lait macules. Initial improvement was achieved in a small nevus spilus after two treatments at 4.5 J/cm², and a larger nevus spilus after one treatment at 7.5 J/cm² with complete removal of the junctional or compound nevi portion but no improvement in the cafe-au-lait portion. Complete return of the background pigment was observed by 1 year. There was no scarring. Immediately after treatment, histology revealed vacuolizaton of keratinocytes and melanocytes, and occasional subepidermal blisters. Conclusions. These findings show that while the Q-switched ruby laser may not be entirely useful for treating nevi spili, it does provide an effective treatment for lentigines and café-au-lait macules.     

Treatment of tattoos by Q-switched ruby laser. A dose-response study

Tattoo treatment with Q-switched ruby laser pulses (694 nm, 40 to 80 nanoseconds) was studied by clinical assessment and light and electron microscopy. Fifty-seven blue-black tattoos or portions thereof (35 amateur and 22 professional) were irradiated with 1.5 to 8.0 J/cm2 at a mean interval of 3 weeks. Substantial lightening or total clearing occurred in 18 (78%) of 23 amateur tattoos and 3 (23%) of 13 professional tattoos in which the protocol was completed. Response was related to exposure dose. Scarring occurred in one case, and persistent confettilike hypopigmentation was frequent. Optimal fluence was 4 to 8 J/cm2. Clinicohistologic correlation was poor. Q-switched ruby laser pulses can provide an effective treatment for tattoos.     

Light and electron microscopic analysis of tattoos treated by Q-switched ruby laser

Short-pulse laser exposures can be used to alter pigmented structures in tissue by selective photothermolysis. Potential mechanisms of human tattoo pigment lightening with Q-switched ruby laser were explored by light and electron microscopy. Significant variation existed between and within tattoos. Electron microscopy of untreated tattoos revealed membrane-bound pigment granules, predominantly within fibroblasts and macrophages, and occasionally in mast cells. These granules contained pigment particles ranging from 2-in diameter. Immediately after exposure, dose-related injury was observed in cells containing pigment. Some pigment particles were smaller and lamellated. At fluences greater than or equal to 3 J/cm2, dermal vacuoles and homogenization of collagen bundles immediately adjacent to extracellular pigment were occasionally observed. A brisk neutrophilic infiltrate was apparent by 24 h. Eleven days later, the pigment was again intracellular. Half of the biopsies at 150 d revealed a mild persistent lymphocytic infiltrate. There was no fibrosis except for one case of clinical scarring. These findings confirm that short-pulse radiation can be used to selectively disrupt cells containing tattoo pigments. The physial alteration of pigment granules, redistribution, and elimination appear to account for clinical lightening of the tattoos.     

Keratinocytes in the depigmented epidermis of vitiligo are more vulnerable to trauma (suction) than keratinocytes in the normally pigmented epidermis, resulting in their apoptosis

BACKGROUND: Vitiligo may develop following minor physical trauma. However, in autologous epidermal grafting, depigmentation of the donor (normally pigmented) site from a suction blister is rare, even in cases displaying failure of repigmentation at the recipient (depigmented) site. OBJECTIVES: To examine whether the suction procedure is more likely to damage keratinocytes in the depigmented than in the normally pigmented epidermis of vitiligo, and to determine what kind of damage occurs to the keratinocytes. METHODS: Paired roofs of suction blisters from five patients with generalized vitiligo, five with localized and seven with segmental type, were used for the study. Multiple new lesions developed in two of the five patients with the generalized type. Apoptosis of keratinocytes in the epidermis was determined by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-digoxigenin nick end labelling (TUNEL) staining, with immunohistochemistry for Bax and active caspase 3. Expression of Bcl-2, Bax, FLIP and p53, activation of caspases 3, 8 and 9, and cleavage of poly(adenosine diphosphate ribose) polymerase (PARP) in the epidermis were analysed by Western blotting in four patients with each type. RESULTS: Apoptotic keratinocytes, which stained with TUNEL and anti-Bax and antiactive caspase 3 antibodies, were scattered in the blistered epidermis, mainly in the lower portions. The depigmented epidermis displayed significantly more apoptotic keratinocytes than the normally pigmented epidermis. The numerical difference between the paired epidermides was related to the disease activity and not to the type of lesions. The number of apoptotic keratinocytes in the normally pigmented epidermis was as high as that in the depigmented epidermis in the two patients with active generalized type vitiligo. Expression of Bax and p53 in the depigmented epidermis was higher than in the normally pigmented epidermis, whereas expression of FLIP was lower. In addition, the activation of caspases 3, 8 and 9, and cleavage of PARP, were increased in the depigmented compared with the normally pigmented epidermis. The degree of difference in expression and activation was parallel to the results of the TUNEL assay. CONCLUSIONS: The keratinocytes in the depigmented compared with the normally pigmented epidermis of vitiligo may become apoptotic more easily after suction.     

Q-switched ruby laser therapy of nevus of Ota.

BACKGROUND--The Q-switched ruby laser has been demonstrated to provide selective photothermolysis of pigmented tissue at a wavelength of 694 nm and a pulse width of 40 ns with dermal penetration. It was used to treat 15 patients with nevus of Ota involving the face with an age range of 6 to 52 years. Other methods of treatment for the nevus of Ota have either left scarring or were ineffective. The clinical efficacy of this laser treatment was evaluated in a comparative photographic analysis. OBSERVATIONS--Complete clearing was noted in four of the 15 patients and a minimum of 50% lightening of the original color in the remaining 11. Ten of the 15 patients were Asian, two were white, two were Hispanic, and one was Indian. The energy fluence used varied between 6 and 10 J/cm2, and the number of treatments ranged from 1 to 7. Significant lightening or clearing was found at the higher energy ranges of 9 to 10 J/cm2 with significantly less lightening noted at the lower energy range of 6 to 8.5 J/cm2. No scarring was noted in any of the 15 patients, and some isolated hypopigmentation was noted in one of the subjects. Transient postinflammatory hyperpigmentation of 2 months' duration was noted in only one patient. CONCLUSION--Q-switched ruby selective photothermolysis appears to be an effective and safe method of lightening or removing nevus of Ota.     

Treatment of vitiligo: current methods and new approaches

Vitiligo is an acquired idiopathic hypomelanotic disorder characterized by circumscribed depigmented maculae. It can be treated in many ways. The choice of therapy is individually adjusted depending on various factors, such as the patient age, type and stage of disease, and affected body site. Current treatment modalities include psoralen with exposure to ultraviolet A (PUVA) radiation therapy, narrow-band UVB therapy, topical corticosteroids, depigmentation therapy with monobenzylether of hydroquinone, and surgical treatments (minigrafting, thin split-thickness grafting, suction blister grafting, micropigmentation). There are also some new treatment modalities, such as 308-nm excimer laser, vitamin D analogues, tacrolimus, depigmentation with Q-switched ruby laser, and grafting of cultured melanocytes.     

Low-fluence carbon dioxide laser irradiation of lentigines

Low-fluence carbon dioxide (CO2) laser irradiation of skin has previously been shown to induce damage limited primarily to the epidermis. To evaluate whether this technique was therapeutically effective for pigmented epidermal lesions, ten lentigines caused by methoxsalen and ultraviolet light therapy were treated in one patient using the CO2 laser at fluences ranging from 3.0 to 7.7 J/cm2 for 0.1-s exposures with 4.5-mm spot size. Based on substantial clearing in seven of ten lesions treated, 146 solar lentigines were treated in five patients at fluences of 3.0, 3.7, or 4.4 J/cm2. Biopsies were performed on a total of 30 lesions immediately and 24 hours, seven days, and six weeks after irradiation. Of 125 lesions followed up clinically for six weeks, 12 cleared completely, 81 lightened substantially, and 28 remained unchanged. Only two demonstrated atrophic change. Hyperpigmentation or hypopigmentation did not occur. All lesions that improved had been treated at 3.7 or 4.4 J/cm2. Immediate histologic injury consisted of vacuolar and spindly change and subsequent vesiculation limited to the basilar epidermis. Twenty-four hours later there was epidermal necrosis with regeneration, 0.1 mm of dermal basophilia and stromal condensation, and a mild inflammatory infiltrate. These alterations were dose-dependent, with near complete epidermal necrosis and superficial dermal involvement at the highest fluence, and only focal epidermal necrosis at the lowest. At seven days, epidermal regeneration was complete with traces of melanin remaining in keratinocytes. Melanophages first appeared at seven days and persisted at six weeks, by which time the inflammatory infiltrate had cleared. No lentiginous proliferation was evident and epidermal pigmentation had become normal. Low-fluence CO2 laser irradiation is an effective means of damaging the epidermis with only minimal dermal change. This mode of therapy is an effective way to lighten the pigmentation of lentigines without substantial scarring.     

Effects of cryogen spray cooling and high radiant exposures on selective vascular injury during laser irradiation of human skin

BACKGROUND: Increasing radiant exposure offers a means to increase treatment efficacy during laser-mediated treatment of vascular lesions, such as port-wine stains; however, excessive radiant exposure decreases selective vascular injury due to increased heat generation within the epidermis and collateral damage to perivascular collagen. OBJECTIVE: To determine if cryogen spray cooling could be used to maintain selective vascular injury (ie, prevent epidermal and perivascular collagen damage) when using high radiant exposures (16-30 J/cm2). DESIGN: Observational study. SETTING: Academic hospital and research laboratory. PATIENTS: Twenty women with normal abdominal skin (skin phototypes I-VI). INTERVENTIONS: Skin was irradiated with a pulsed dye laser (wavelength = 585 nm; pulse duration = 1.5 milliseconds; 5-mm-diameter spot) using various radiant exposures (8-30 J/cm2) without and with cryogen spray cooling (50- to 300-millisecond cryogen spurts). MAIN OUTCOME MEASURE: Hematoxylin-eosin-stained histologic sections from each irradiated site were examined for the degree of epidermal damage, maximum depth of red blood cell coagulation, and percentage of vessels containing perivascular collagen coagulation. RESULTS: Long cryogen spurt durations (>200 milliseconds) protected the epidermis in light-skinned individuals (skin phototypes I-IV) at the highest radiant exposure (30 J/cm2); however, epidermal protection could not be achieved in dark-skinned individuals (skin phototypes V-VI) even at the lowest radiant exposure (8 J/cm2). The red blood cell coagulation depth increased with increasing radiant exposure (to >2.5 mm for skin phototypes I-IV and to approximately 1.2 mm for skin phototypes V-VI). In addition, long cryogen spurt durations (>200 milliseconds) prevented perivascular collagen coagulation in all skin types. CONCLUSIONS: Cryogen spurt durations much longer than those currently used in therapy (>200 milliseconds) may be clinically useful for protecting the epidermis and perivascular tissues when using high radiant exposures during cutaneous laser therapies. Additional studies are necessary to prove clinical safety of these protocols.     

Treatment of acquired junctional melanocytic naevi by Q-switched and normal mode ruby laser

BACKGROUND: Acquired junctional melanocytic naevi are harmless pigmented lesions of the epidermis, which can be of cosmetic concern. Various therapeutic approaches have been used in the treatment, but all these methods produce postoperative scarring or alterations in skin texture. Pigment laser treatment of benign pigmented lesions has shown a low potential for scarring by selectively targeting melanosomes in melanocytes and keratinocytes. OBJECTIVE: To find a fast, effective and safe treatment for the removal of acquired junctional melanocytic naevi. PATIENTS/METHODS: We first studied the effect of the Q-switched and normal mode ruby laser on 12 patients (eight women and four men) with acquired melanocytic naevi. The effect was monitored by histology and clinical photography. RESULTS: If the response to one treatment with the Q-switched laser mode was not completely effective, the lesions were subsequently treated with one or two sessions with the laser in normal mode. All flat lesions responded completely. After a follow-up period of 1 year they had not recurred. Slightly elevated lesions showed only a partial response, e.g. disappearance of the junctional part of the naevus but recurrence of the dermal part of the naevus. Red-brown junctional naevi as seen in skin types I and II did not respond well to ruby laser treatment. CONCLUSIONS: The Q-switched ruby laser was very successful in completely removing flat (non-palpable) acquired junctional melanocytic naevi, but not compound naevi, with one to three treatment sessions, without any scarring or pigmentary disturbance.     

Successful Treatment of Dark-colored Epidermal Nevus with Ruby Laser

The pulsed ruby laser has a selective thermolytic effect. Recently, it has been available for the treatment of superficial pigmented disorders. We studied 5 cases of epidermal nevus treated with the pulsed ruby laser. In comparison with the usual methods including electrocautery, cryotherapy and skin abrasion, ruby laser therapy is an excellent tool due to technological ease and rapid improvement. Depigmentation after treatment in 2 cases was the only side effect of this therapy. Bose cases had a dark pigmentation of the skin. Despite of the risk of discoloration, the ruby laser is one of the most effective tools for therapy of pigmented epidermal nevus.     

Depigmentation therapy

ABSTRACT: Depigmentation therapy is a treatment option for patients with widespread, treatment-resistant vitiligo. The most commonly employed technique is the application of monobenzylether of hydroquinone (MBEH), also known as monobenzone, to areas with residual pigment. Prior to instituting therapy, the patient must be aware of the cost, treatment time course, risk of distant sites of depigmentation, probable permanency of depigmentation, side effects such as contact dermatitis, and the potential for repigmentation via follicular melanocytes. The social ramifications of depigmentation therapy also must be discussed, especially for patients with skin types IV and V. The sequential use of 4-methoxyphenol and Q-switched ruby laser also has been reported as a successful form of depigmentation therapy.     

Long-pulsed Nd:YAG laser-assisted hair removal in pigmented skin: a clinical and histological evaluation.

OBJECTIVE: To determine the safety and effectiveness of a long-pulsed Nd:YAG laser at 1064 nm in effecting long-term hair reduction in patients with darkly pigmented skin. DESIGN: Nonrandomized before-after clinical and histological trial. SETTING: Private practice, ambulatory care facility. PATIENTS: Twenty women with skin phototypes IV through VI and dark brown to black terminal hair on the face, axillae, or legs. INTERVENTION: A series of 3 long-pulsed (50-millisecond) 1064-nm Nd:YAG laser treatments at fluences ranging from 40 to 50 J/cm(2) were delivered to the identified treatment areas on a monthly basis by a single operator. MAIN OUTCOME MEASURES: Global clinical grading scores of comparable before-after treatment photographs were determined by 2 independent medical assessors during each laser session and 1, 3, 6, and 12 months postoperatively. A dermatopathologist reviewed unmarked histological specimens obtained at baseline, immediately after the initial laser treatment, and at 1 and 6 months after the final laser session. RESULTS: Substantial hair reduction was seen after each of the 3 treatment sessions. Prolonged hair loss was observed 12 months after the final laser treatment (70%-90% hair reduction). Axillary hair was substantially more responsive to laser irradiation than was hair located on the legs and face. Adverse effects included mild to moderate treatment pain and rare occurrences of vesiculation and transient pigmentary alteration without fibrosis or scarring. Histological tissue changes mirrored clinical response rates, with evidence of selective follicular injury without epidermal disruption. CONCLUSION: The long-pulsed 1064-nm Nd:YAG laser is a safe and effective method of long-term hair reduction in patients with darkly pigmented skin.     

Histological hair removal study by ruby or alexandrite laser with comparative study on the effects of wavelength and fluence.

BACKGROUND: Several different laser systems are currently used to remove unwanted hairs. In this study, we studied follicular changes following hair removal with ruby or alexandrite lasers at different fluences. METHODS: Unwanted hairs were treated with a ruby laser (Chromos 694, ICN PhotonIcs, UK) at 10, 14 or 18 J/cm2 or with an alexandrite laser (LPIR, Cynosure, USA) at 11, 14 or 17 J/cm2. A 3 mm skin punch biopsy was taken immediately after each laser exposure and also 1 month later. Specimens were stained for histological observation. They were observed using immunohistochemistry with antibodies recognizing factor VIII related antigen or PCNA, and also by the TUNEL method. Similarly, electron microscopic observation was examined. RESULTS: Immediately after the laser exposure, moderate follicular damage was observed following treatment with either type of laser. One month later, cystic formation of hair follicles and foreign body giant cells were observed in skin treated with either type of laser. A similar fluence with either laser treatment resulted in similar histological changes. CONCLUSION: In this study, the histological changes following treatment with a ruby or an alexandrite laser at the same fluence are similar.     

A clinical and histologic prospective controlled comparative study of the picosecond titanium:sapphire (795 nm) laser versus the Q-switched alexandrite (752 nm) laser for removing tattoo pigment

BACKGROUND: Theory predicts that picosecond lasers should be more effective than the currently available nanosecond lasers in removing tattoo ink. In addition to thermal confinement, such pulse widths cause optimal photomechanical disruption of the target. OBJECTIVE: This study compared the efficacy of the picosecond titanium:sapphire (795 nm, 500 psec) laser and the Q-switched alexandrite (752 nm, 50 nsec) laser in the treatment of tattooed guinea pigs. METHODS: Six albino guinea pigs, each with 6 uniformly 1 cm circular black tattoos, were treated. Three of the tattoos were divided into 2; one half was treated with the titanium:sapphire laser and the other half with the alexandrite laser. Fluences used for both lasers were 6.11, 4.24, and 2.39 J/cm2 with spot sizes of 1.25, 1.5, and 2 mm, respectively. The remaining spots served as control. Clinical evaluation and biopsies were performed at baseline and at 11 and 16 weeks after a single laser treatment. RESULTS: Greater clearance of tattoo was observed in titanium:sapphire laser-treated areas in 2 of the 4 surviving guinea pigs. In some areas total clearing was observed after the single titanium:sapphire laser treatment. Clearing improved with higher fluences. No scarring was present. Histologic results showed similar findings. CONCLUSION: Our findings suggest that the picosecond titanium:sapphire laser is more effective than the Q-switched alexandrite laser in removing tattoo pigment and may be of significant clinical utility.     

Alterations in cutaneous immune reactivity to dinitrofluorobenzene in graying C57BL/vi.vi mice

The fur of the C57BL/vi.vi mouse is black at 6 weeks of age. By 6 months of age the animals are white and there are no identifiable pigment cells within the epidermis or hair bulbs. Human subjects with vitiligo exhibit loss of epidermal pigment cells. The loss of pigment cells in human subjects with vitiligo has been associated with loss of cutaneous immune reactivity to contact allergens. Therefore, studies were performed to determine whether loss of pigment cells in these depigmenting mice also was associated with loss of the cutaneous immune response. The number of Ia-positive (Ia +) Langerhans cells (LC)/mm2 on the back and the ear, the sites of sensitization and challenge with dinitrofluorobenzene (DNFB), was quantified before, during, and after depigmentation. We observed that there were fewer LC/mm2 on the back and the ear before and after pigment loss in the graying mice than in the normal control C57BL/6 mice. The young pigmented C57BL/vi.vi mice were capable of developing moderate contact hypersensitivity; the older depigmented mice did not sensitize to DNFB. We conclude that the depigmented mice, like human subjects with vitiligo, have a loss of contact hypersensitivity associated with a loss of pigment cells within the epidermis. In the mouse, loss of melanocytes is associated with a decrease in the population density of Ia + cells.     

Ultrastructure: effects of melanin pigment on target specificity using a pulsed dye laser (577 nm)

It has been shown recently that brief pulses of 577 nm radiation from the tunable dye laser are absorbed selectively by oxyhemoglobin. This absorption is associated with highly specific damage to superficial vascular plexus blood vessels in those with lightly pigmented (type I-II) skin. To determine whether pigmentary differences in the overlying epidermis influence this target specificity, we exposed both type I (fair) and type V (dark) normal human skin to varying radiant exposure doses over 1.5-microsecond pulse durations from the tunable dye laser at a wavelength of 577 nm. Using ultrastructural techniques, we found in type I skin that even clinical subthreshold laser exposures caused reproducible alterations of erythrocytes and adjacent dermal vascular endothelium without comparable damage to the overlying epidermis. In contrast, degenerated epidermal basal cells represented the predominant form of cellular damage after laser exposure of type V skin at comparable doses. We conclude that epidermal melanin and vascular hemoglobin are competing sites for 577 nm laser absorption and damage, and that the target specificity of the 577 nm tunable dye laser is therefore influenced by variations in epidermal pigmentation. This finding is relevant to the clinical application of the tunable dye laser in the ablative treatment of vascular lesions. We also found on ultrastructure that the presence of electron-lucent circular structures of approximately 800 A in diameter were observed only at and above clinical threshold doses in those with type I skin and at the highest dose of 2.75 J/cm2 in type V skin. It has been proposed that these structures might be heat-fixed molds of water vapor. Both this and ultrastructural changes of epidermal basal cells demonstrate mechanisms responsible for alteration of tissue after exposure to 577 nm, which are discussed.     

A case of extramammary Paget's disease with depigmented macules as the sole manifestation

Summary We report a 76-year-old man who had four depigmented macules in the genital area as the sole manifestation of extramammary Paget's disease (EMP). Histologically, many scattered, dissociated, plump Paget cells, and small intraepidermal nests of these cells were seen in all four lesions. The distribution of Paget cells extended beyond the margin of the depigmented areas into adjacent normally pigmented skin. Fontana–Masson staining revealed a reduction in, or absence of, melanin deposition along the basal layer of the depigmented lesions, in contrast with an abundance of melanin along the basal layer of the adjacent normal skin. Pigment-blockade melanocytes and melanophages were seen within or below the affected epidermis. The depigmentation in this case could have been caused by a symbiotic disorder between melanocytes and keratinocytes (including melanocyte destruction), and by a disorder in melanosome transmission to the keratinocytes. This case illustrates that a depigmented macule may be a diagnostic feature of EMP. Moreover, depigmentation is probably one of the earliest clinical features of EMP, and not a neighbouring secondary change such as occurs in the Sutton's halo naevus phenomenon.     

Successful treatment of disseminated superficial actinic porokeratosis with Q-switched ruby laser

Porokeratosis, a cutaneous disorder that is characterized histologically by the presence of a "cornoid lamella", is a progressive disease with limited therapeutic modalities. We report a case of a 61-year-old man suffering from disseminated superficial actinic porokeratosis, one of the clinical types of porokeratosis, treated with Q-switched ruby laser, commonly used for the treatment of pigmented skin diseases. The laser therapy provided striking improvement and no clinical recurrence was noted.     

Laser therapy of pigmented lesions: pro and contra

Although frequently performed, laser removal of pigmented lesions still contains certain controversial issues. Epidermal pigmented lesions include solar lentigines, ephelides, café au lait macules and seborrheic keratoses. Dermal lesions include melanocytic nevi, blue nevi, drug induced hyperpigmentation and nevus of Ota and Ito. Some lesions exhibit both an epidermal and dermal component like Becker's nevus, postinflammatory hyperpigmentations, melasma and nevus spilus. Due to the wide absorption spectrum of melanin (500-1100 nm), several laser systems are effective in removal of pigmented lesions. These lasers include the pigmented lesion pulsed dye laser (510 nm), the Q-switched ruby laser (694 nm), the Q-switched alexandrite laser (755 nm) and the Q-switched Nd:YAG laser (1064 nm), which can be frequency-doubled to produce visible green light with a wavelength of 532 nm. The results of laser therapy are usually successful. However, there are still many controversies regarding the use of lasers in treating certain pigmented lesions. Actually, the essential question in removing pigmented lesions with lasers is whether the lesion has atypical features or has a malignant potential. Dermoscopy, used as a routine first-level diagnostic technique, is helpful in most cases. If there is any doubt whether the lesion is benign, then a biopsy for histologic evaluation is obligatory.