A Pilot Split-Neck Case Study to Compare the Efficacy of the Long-Pulsed 755 nm Laser and the 532 nm Picosecond Laser for Acrochordon Removal

Abstract

Cutaneous papillomas or acrochorda usually appear after the 4th decade of life in areas with skin folds. Conventional methods of removal are associated with bleeding problems, pain and prolonged sequelae. Thus, acrochorda removal with lasers has gained attention. In this study, we compared the efficacy of two popular laser types with different wavelengths and pulse widths for removal of skin tags. A 60-year-old Korean male noticed skin tags on his neck bilaterally. All tags were treated in a single session, on one side with a picosecond (ps)-domain 532 nm Nd:YAG laser and on the contralateral side with a long-pulsed (LP) 755 nm alexandrite laser. The endpoint for the ps-532 laser was immediate whitening, while that for the LP and quasi-LP (QLP) 755 lasers were visible changes on the surface of the lesion. Antibiotic ointment was applied, dressing was done and clinical photographs were taken. Both lasers effectively removed the skin tags at all settings in a single session without bleeding and with minimal discomfort. Crust formation occurred on both sides with natural shedding within 1 to 2 weeks. Transient erythema lasted longer in the tags treated with the ps-532 laser. At the 5th month of follow-up, residual lesions were detected on the field treated with the ps-532 laser. No persistent side effects such as scarring or postinflammatory hyperpigmentation (PIH) were observed. In conclusion, both the ps-532 nm Nd:YAG and the 755 nm alexandrite lasers ensured safe and effective removal of skin tags in a single session without adverse sequelae.

INTRODUCTION

Cutaneous papillomas, also known as soft fibromas, acrochorda and more commonly as skin tags, are soft excrescences of bunched up skin seen in 50% to 60% of the population with an almost 100% occurrence in recent years¹,². Common sites of occurrence include the eyelids, neck, axillae, and groin³,⁴. Although their etiology remains unclear, skin-skin friction has been implicated, because these tags are often found in areas with skin folds⁵.

Histopathological analysis of acrochorda reveals a mildly hyperkeratotic epidermis covering a fibrovascular core. The epidermis may be hyperpigmented to a certain extent, in the majority of lesions, and the tumor may be connected to the skin by a thin pedunculated stalk, or raised from the surrounding normal skin. The degree of vascularization of the core determines the amount of bleeding during removal.

Conventional methods of removal include electrocautery, snip excision, ligation or cryotherapy. However, skin tags are usually difficult to treat without some form of local anesthesia, and control of bleeding is important following surgical removal. In addition, wound dressing is frequently indicated for a certain period of time. Also, it may be associated with side effects such as post-inflammatory hyperpigmentation, longer healing time or scars. Use of lasers, such as carbon dioxide (CO₂) or Q-switched Nd:YAG lasers⁶,⁷, has gained popularity as it combines the cauterization and hemocoagulative powers of laser energy. In the present study, the efficacy of two different laser types, the 532 nm picosecond Nd:YAG laser and a long-pulsed (LP) 755 nm alexandrite laser, for skin tag removal was compared using both the LP and quasi long-pulsed (QLP) modes.

CASE REPORT

A 60-year-old Korean male noticed multiple skin tags on his neck bilaterally (Fig. 1). The skin tags on the right side were treated with a long-pulsed 755 nm alexandrite laser (ClarityII; Lutronic Corporation) with the following settings: spot size, 3 mm; pulse width, 3 ms; pulse energy, 45~60 J (LP-755 group): or spot size, 3 mm; pulse width, 300 µs (QLP); and pulse energy, 50 J (QLP-755 group). Skin tags on the left side were treated with a picosecond (ps)-domain 532 nm Nd:YAG laser (PicoPLUS; Lutronic Corporation) with the following settings: spot size, 2.3 mm; pulse width, 450 ps; fluence, 0.8 J/cm²; and pulse rate, 1 Hz (ps-532 group). Both sides of skin tags were treated mostly with 1 pass of laser exposure except few lesions that insufficient to reach primary endpoint. The endpoint for the ps-532 group was immediate whitening with a halo of erythema, whereas that for the LP- and QLP-755 groups were visible changes on the surface of the lesion with some erythema. Antibiotic ointment and a small dressing were applied for 2 days after the treatment. Clinical photographs were taken at baseline, immediately after treatment, and 1, 2, and 6 weeks after treatment. Pain was scored on a visual analogue scale (VAS).

Fig. 1. Acrochorda (skin tags) on the bilateral neck of a 60-year-old Korean male at baseline. The tags on the right side were assigned to treatment with a long-pulsed 755 nm alexandrite laser whereas those on the left to treatment with a 532 nm picosecond Nd:YAG laser.

Both lasers effectively removed the skin tags at all settings in a single session without bleeding and with minimal discomfort. VAS scores for the ps-532 and LP- and QLP-755 groups were similar (2 to 3), due to application of the topical anesthetic. Transient erythema was seen after all treatments, which was marginally higher and lasted longer in the ps-532 group. Crusting was seen in all treated tags and natural shedding of all crusts occurred between 1 and 2 weeks post-treatment. No adverse events or persistent side effects, such as postinflammatory hyperpigmentation (PIH) or scar formation, were observed in any of the treated tags. The findings immediately after treatment and at 2 weeks post-treatment are shown in Fig. 2, 3. The final assessment at 6 weeks after the treatment is shown in Fig. 4.

Fig. 2. Clinical photography of findings immediately after treatment (front view). The right side was assigned to a long-pulsed 755 nm alexandrite laser and the left side was assigned to 532 nm picosecond Nd:YAG laser.

Fig. 3. The findings immediately after treatment (lateral view); (A) 532 picosecond Nd:YAG laser and (B) 755 nm long-pulsed alexandrite laser. The findings at two weeks after treatment; (C) 532 picosecond Nd:YAG laser and (D) 755 nm long-pulsed alexandrite laser.

Fig. 4. The findings at the final assessment, six weeks after the single treatment. The left side was treated with the 532 picosecond Nd:YAG laser and the right side with the 755 nm long-pulsed alexandrite laser. Both systems have successfully cleared the acrochorda with no postinflammatory hyperpigmentation or scarring.

There were no differences between the ps-532 and LP- and QLP-755 groups 1 and 2 weeks after the treatment. But at the 5th month of follow-up, minor residual acrochorda lesions were observed on the left side, but not new lesions, which was treated with ps-532 nm Nd:YAG laser. There was no difference between LP- and QLP-755 groups at the 5th month period. We received the patient’s consent form about publishing all photographic materials.

DISCUSSION

Acrochorda may be cosmetically displeasing to some individuals, and are prone to inflammation in the event of frictional contact with clothing or jewelry. Considering their predominantly benign nature, removal should ideally be painless, swift and devoid of side effects. Conventional methods require anesthesia and have been associated with bleeding, PIH, and scar formation.

The efficacy of lasers, particularly the ablative CO₂ and Er:YAG lasers, for acrochorda removal has gained attention considering their high affinity for water and ‘color blind’ nature⁶,⁷. CO₂ laser is preferred as it leads to deposition of a layer of secondary thermocoagulation, the residual thermal damage (RTD) which is the holy grail for full-face ablative resurfacing⁸. The RTD zone ensures good hemocoagulation in skin tags with a strong vascular component. In contrast, the Er:YAG laser must be used with caution, as it does not produce deep secondary coagulation owing to its order of magnitude better absorption in water. Therefore, it may be associated with the potential for hemorrhage.

The CO₂ and Er:YAG lasers have photothermal ability, depending on the conversion of light energy to heat on absorption by the target tissue. More recently, the ps-laser has gained attention in the removal of pigmented lesions and skin rejuvenation⁹,¹⁰. Unlike the Q-switched nanosecond domain laser, the ps-laser exerts its effect through a photomechanical mechanism with a minor photothermal component, owing to its ultra-short pulse width combined with extremely high peak power densities. Accordingly the present pilot study was designed to compare the efficacy of the ps-532 nm laser at a 450 ps pulse width for skin tag removal with a LP 755 nm alexandrite laser with two different pulse widths, 3 ms and 300 µs, both purely photothermal in their mechanism of action. To our knowledge, this is the first study to compare this aspect.

The results demonstrated that both lasers rapidly and effectively removed the target lesions nearly in a single pass of laser exposure with minimal pain and no persistent side effects. This has strength in that it shortens time and improves treatment efficacy compared with conventional lasers destruction which usually requires multiple passes for removal. In addition, using both lasers reduces the risk of control of bleeding non-invasively and shortens healing time than conventional treatment while achieving comparable efficacy. Erythema was marginally more evident in the ps-532 group than in the LP- and QLP-755 groups. To deliver fluence of 0.8 J/cm² over the 2.3 mm spot, as used in this study, the system has to develop an extremely high peak power density of 1.8 GW/cm². The power density or irradiance is the prime determinant of tissue reaction. The tissue reaction is almost athermal and nonlinear, approaching, if not exceeding the threshold of tissue optical breakdown in cases of high power density and ultra-short pulse width. This resulted in the white change in the skin of the target lesions and should not be confused with the so-called frosting which is the usual endpoint when the ns-domain 532 nm wavelength is used for removal of discrete epidermal pigmented lesions. In other words, there was a combination of a photoosmotic and photoacoustic shocks, resulting in the overall photomechanical effect that cleanly destroyed the skin tags. The 5th month follow-up result showed that residual skin tag lesions persisted in the ps-532 group. It is considered that the LP 755 nm alexandrite laser provides deep coagulation; therefore, skin tags were removed more efficiently in the LP- and QLP-755 groups based on the morphological type of the tags.

Another interesting aspect was the comparison of the irradiances delivered by the 755 nm alexandrite laser and the two pulse widths used. The spot size for both was 3 mm, and the energies for the 3 ms and 300 µs pulse widths were 45~60 J and 50 J, respectively. First, the difference between the pulse widths was significant, wherein 3 ms is a true LP, whereas 300 µs is a micropulse, or QLP. Furthermore, the thermal relaxation time (TRT) for skin in general is ≤1 ms; thus, the 3 ms pulse was above, whereas the 300 µs pulse was below the TRT. Despite the short sub-TRT pulse width, the resulting photothermal effect was greater in the QLP-755 treated acrochorda, and the final erythema was similar in both the LP- and QLP-755-treated tags.

The major limitation of the present pilot study is that, despite being a split-neck study, it was performed on a single subject; therefore the results cannot be generalized without further studies in larger populations. Also, further studies about different endpoints and treatment responses in other ethnic groups such as Caucasian or Black persons might be needed.

Acrochorda on the neck were successfully removed in an Asian skin-type patient with minimal pain in a single session using a ps 532 nm Nd:YAG and LP- and QLP-755 nm alexandrite lasers. Our results suggest that both laser modalities can be considered a novel, simple and rapid treatment option for troublesome skin tags.