warts are benign epithelial neoplasms of the skin and mucosa resulting from human papillomavirus ( hpv ) infection .
they are a common dermatologic complaint , with an estimated incidence of 10% in children and young adults ( 1 ) .
even if disease progression is naturally self - limited , the course of the disease is unpredictable , and treatment may be necessary .
several treatment methods are available for treatment of warts ; however , most methods have specific disadvantages and side effects .
topical management requires the application of drugs for long durations and treatment success is , therefore , highly dependent on patient compliance ( 2 ) .
laser treatment is based on the principle of photodermal or photomechanical destruction of the target tissue .
depending on the pulse duration and energy density , this may result in the coagulation ( photodermal effect ) or blasting ( photomechanical effect ) of these structures ( 2 ) .
many studies have used 585-nm pulsed dye lasers for the treatment of warts , with the wart blood vessels as the target tissue ( 1 - 4 ) .
this is because hemoglobin in blood has strong absorption peaks at wavelengths ranging from 585 to 595 nm ( 5 ) .
moreover , hemoglobin has a significant , albeit more modest , absorption peak between 800 and 1,100 nm .
therefore , it has been postulated that 1,064-nm nd : yag lasers could be used in the treatment of telangiectases ( 5 ) .
in addition , since there is decreased light absorption by melanin at this wavelength , there is reduced risk of pigmentary side effects ( 4 ) .
previous studies have shown that 1,064-nm nd : yag lasers used at longer widths can be used to treat telangiectasias of the lower extremities ( 5 ) , face ( 6 ) , and venous lake ( 7 ) .
we used a long - pulsed nd : yag laser in the treatment of warts , with the wart blood vessels as the target , and evaluated clinical outcomes .
over the course of 1 yr , 369 patients ( mean age , 21 yr ; range , 3 - 67 yr ) ( table 1 ) with recalcitrant or untreated warts were treated with a long - pulsed nd : yag laser .
informed written consent was obtained from all participants before inclusion in the study . in all , 21 patients were lost during follow up , and therefore , the data of 348 patients were evaluated .
warts were classified into three types - verruca vulgaris ( 212 patients ) , deep palmoplantar warts ( 68 patients ) , and periungual warts ( 68 patients ) .
prior to the study , photographs of all the lesions were taken and the size of each lesion was recorded .
the study employed a 1,064-nm long - pulsed nd : yag laser ( cutera , inc . ,
the following parameters were used : spot size , 5 mm ; pulse duration , 20 msec ; and fluence , 200 j / cm . prior to laser treatment
, warts were treated with emla cream or a local lidocaine injection and were peeled with a razor blade .
one or two courses of slightly overlapping laser pulses were applied to each wart , covering the wart itself and a 1-mm margin on the surrounding skin . around the third treatment date , crusts were found to be formed on the treated parts . at 1 to 2 weeks after treatment
, the crusts were removed , and the warts were cleared , leaving only a small scar ( figs . 5 - 7 ) .
clearance was defined as the complete absence of a clinically apparent wart , and treatment failure was defined as a persistent lesion after four treatments .
over the course of 1 yr , 369 patients ( mean age , 21 yr ; range , 3 - 67 yr ) ( table 1 ) with recalcitrant or untreated warts were treated with a long - pulsed nd : yag laser .
informed written consent was obtained from all participants before inclusion in the study . in all , 21 patients were lost during follow up , and therefore , the data of 348 patients were evaluated .
warts were classified into three types - verruca vulgaris ( 212 patients ) , deep palmoplantar warts ( 68 patients ) , and periungual warts ( 68 patients ) .
prior to the study , photographs of all the lesions were taken and the size of each lesion was recorded .
the study employed a 1,064-nm long - pulsed nd : yag laser ( cutera , inc . ,
the following parameters were used : spot size , 5 mm ; pulse duration , 20 msec ; and fluence , 200 j / cm . prior to laser treatment
, warts were treated with emla cream or a local lidocaine injection and were peeled with a razor blade .
one or two courses of slightly overlapping laser pulses were applied to each wart , covering the wart itself and a 1-mm margin on the surrounding skin . around the third treatment date , crusts were found to be formed on the treated parts . at 1 to 2 weeks after treatment
, the crusts were removed , and the warts were cleared , leaving only a small scar ( figs . 5 - 7 ) .
clearance was defined as the complete absence of a clinically apparent wart , and treatment failure was defined as a persistent lesion after four treatments .
the average number of treatment sessions required for clearance was 1.49 ( range , 1 - 4 sessions ) ( fig .
64% of warts were cleared , while 96% ( 336/348 ) of warts were cleared after the fourth treatment ( fig .
2 ) . verruca vulgaris responded better than the other types of warts and required fewer treatments for clearance ( mean , 1.35 sessions ) .
1 ) . the clearance rate after the first treatment was also higher in the verruca vulgaris group ( 72.6% ) than 64.7% in the periungual warts group and 44.1% in the deep palmoplantar warts group ( fig .
the size of the warts was reduced by an average of 10% based on the diameter .
this was observed in 69.1% of the verruca vulgaris warts , 52.5% of the periungual warts , and 27.4% of the deep palmoplantar warts .
histopathologic examination after treatment showed separation of the dermoepidermal junction , epidermal necrosis , and red blood cell ( rbc ) extravasation .
destroyed blood vessels surrounded by a dense inflammatory infiltrate were also shown in the dermis ( fig .
4 ) . since most ( 82% ) patients who were anesthetized with emla cream complained of serious pain during treatment , local lidocaine injections were administered during the second treatment .
other side effects included transient numbness ( 15% ) , hemorrhagic bullae ( 7% ) , hyperpigmentation ( 5% ) , and hypopigmentation ( 4% ) .
in addition , 2% of patients with periungual warts experienced nail dystrophy . during a median follow - up period of 2.24 months ( range , 2 - 10 months ) ,
warts are very common , with an incidence of approximately 10% in children and young adults .
approximately 70% of these patients were between 10 and 39 yr of age , and 50% presented to a dermatologist .
these complications , along with cosmetic embarrassment and risk of translocation to other areas of the skin , are indications for treatment , which can be challenging .
many different types of therapy have been used in the treatment of warts ( 9 - 13 ) .
commonly used methods of physical destruction include surgical excision , electrodesiccation , cryosurgery , and pulsed dye or carbon dioxide laser therapy .
chemical destruction can be induced with salicylic acid , cantharidin , formaldehyde , or glutaraldehyde , among other agents .
more recently , immunomodulators such as interferon , systemic retinoids , cimetidine , and topical imiquimod have been used ( 14 - 16 ) .
this prospective study evaluated the efficacy of long - pulsed nd : yag lasers in the treatment of warts .
the results show that long - pulsed nd : yag lasers are a safe and effective approach to wart treatment , with clearance rates higher than those achieved with other common therapies .
previous studies of cryotherapy in the treatment of warts report clearance rates ranging from 63% to 69% ( 10 , 17 , 18 ) . in a study using imiquimod , 56% of the patients reported total clearance ( 19 ) .
the pooled data from six randomized controlled studies demonstrated a cure rate of 75% in those treated with salicylic acid compared with 48% in the control group ( 21 ) .
one study performed using bleomycin prick method demonstrated complete resolution of warts in 92% of participants ( 22 ) .
long - pulsed nd : yag lasers emit a visible light spectrum at 1,064 nm .
when a 1,064-nm long - pulsed nd : yag laser is used on the skin , a short , strong laser pulse is absorbed by red structures such as cutaneous blood vessels . as a result , blood vessels heat up rapidly and burst . upon blood vessel rupture ,
the mechanism of action of a long - pulsed nd : yag laser in the treatment of warts is not fully understood .
dilated vessels in the papillary dermis are a characteristic feature of warts ( 23 ) .
light microscopic evaluation of treated areas at 7 days after treatment in this study showed separation of the dermoepidermal junction , epidermal necrosis , and rbc extravasation .
in addition to these findings , destroyed blood vessels in the dermis were found to be surrounded by a dense inflammatory infiltrate .
this destruction may obliterate the nutrient supply to the wart or destroy the rapidly dividing epidermal cells that contain hpv .
minimal destruction of the surrounding tissue is anticipated with long - pulsed nd : yag lasers . in our study , the overall clearance rate was 96% ( 336 of the 348 treated warts were eradicated ) . the clearance rate of verruca vulgaris after the first treatment was very high ( 72.6% ) , whereas the clearance rate of deep palmopantar warts after the first treatment was low ( 44.1% ) .
the average number of treatments required for clearance was 1.49 . during a median follow - up period of 2.24 months ( range , 2 - 10 months ) ,
11 relapses were seen ( recurrence rate 3.3% ) . this low recurrence rate seems to be due to the short follow - up period in this study ; therefore , a study with a longer follow - up period and examination of recurrence is needed . the clearance rate after pulsed dye laser treatment , which employs the same mechanism of action as the nd : yag laser , has been reported to be 48% to 92% ( 1 - 4 ) , while the laser used in the current study showed a higher clearance rate ( 96% ) . therefore , a comparative study between these two types of lasers is required .
side effects noted in our study included transient pain during treatment ( 82% ) , posttreatment numbness ( 15% ) , hemorrhagic bullae ( 7% ) , hyperpigmentation ( 5% ) , and hypopigmentation ( 4% ) .
side effects were generally mild and did not prevent normal activity . in conclusion , long - pulsed nd : yag lasers are a safe and effective treatment for warts , with response rates higher than those obtained with conventional therapies .
no single optimal treatment has been inclicated for warts ; therefore , long - pulsed nd : yag lasers should be considered a reasonable addition to the therapeutic options available .
future studies examining optimal laser parameters and treatment intervals would expand our knowledge on how best to use long - pulsed nd : yag laser therapy in managing warts .
 various treatment methods have been adopted in the management of warts ; however , there is still no consensus on first - line treatment . 
 this study was designed to evaluate the efficacy of long - pulsed nd : yag laser in the treatment of warts . over the course of 1 
 yr , 369 patients with recalcitrant or untreated warts were exposed to a long - pulsed nd : yag laser . 
 the following parameters were used : spot size , 5 mm ; pulse duration , 20 msec ; and fluence , 200 j / cm2 . 
 no concomitant topical treatment was used . in all , 21 patients were lost during follow up ; hence , the data for 348 patients were evaluated . 
 the clearance rate was 96% ( 336 of the 348 treated warts were eradicated ) . the clearance rate of verruca vulgaris after the first treatment was very high ( 72.6% ) , whereas the clearance rate of deep palmopantar warts after the first treatment was low ( 44.1% ) . during a median follow - up period of 2.24 months ( range , 2 - 10 months ) , 
 11 relapses were seen ( recurrence rate , 3.27% ) . in conclusion , 
 long - pulsed nd : yag laser is safe and effective for the removal or reduction of warts and is less dependent on patient compliance than are other treatment options . 
INTRODUCTION
MATERIALS AND METHODS
Patients
Treatment
RESULTS
DISCUSSION