molluscum contagiosum ( mc ) is a commonly encountered cutaneous viral infection in children , its hallmark being spontaneous resolution . despite its benign nature , active therapy may be desirable to prevent further spread , relieve symptoms , prevent scarring , and for cosmetic , and social reasons . parental concern is valid as these lesions appear unsightly and the affected children may face isolation by their peers . treatment modalities include : mechanical destruction by curettage , cryotherapy or evisceration ; chemical destruction of the lesions using potassium hydroxide ( koh ) or cantharidin ; immunomodulatory agents such as topical imiquimod , tretinoin and oral cimetidine ; and the antiviral agent cidofovir . in spite of options galore , no single therapy has consensus approval for the treatment of mc in the pediatric age group . mechanical destruction of lesions is the easiest method among adults , but in children , owing to fear and lower tolerance of pain , these methods can not be used routinely . studies examining response to laboratory pain stimuli in children have shown that asians demonstrated more pain sensitivity compared to other ethnic groups . furthermore , parents do not favor frequent visits to the hospital as children exhibit high levels of anticipatory anxiety . thus , there is a need for a therapeutic modality that can be used at home and is not painful . it has been used in various concentrations , that is , 5% , 10% , and 20% , for the treatment of mc . it has been shown to possess an excellent safety profile in the treatment of cutaneous viral diseases . taking this into consideration , we undertook a randomized comparative study to assess and compare the efficacies of 10% koh aqueous solution and 5% imiquimod cream for the treatment of mc in the pediatric age group . after obtaining permission from the institutional ethics committee , 40 patients between the age group of 1 - 18 years with minimum 3 lesions of mc were recruited to this study . patients with eyelid involvement , secondary infection and history of hypersensitivity to imiquimod were not enrolled in the study . details of symptoms , duration , family history , site , and number of lesions were recorded . patients were divided by the lottery method into two groups ; a and b , each containing 20 patients . patients in group a were given 5% imiquimod cream in 0.25 g sachets ( galderma ) and their parents advised to apply it as a thin layer , rubbing it until it was no longer visible . patients in group b were given 10% koh solution with instructions to the parents to apply using a tooth pick after covering the surrounding area with petrolatum and avoid any spillage over normal skin . both groups were advised to apply the respective agents at night and wash off in the morning , 3 times a week for 12 weeks or until the lesions cleared , whichever was early . patients were followed up at 4 , 8 and 12 week of treatment . on each visit , clinical response to treatment , efficacy , and tolerability parameters were evaluated . the clinical response to treatment was graded as complete clearance , partial clearance and no change . data were analyzed using chi - square test , fishers exact test and friedman test , whereas pairwise comparison was done by wilcoxon signed rank test and mann - whitney test . maximum number of cases were in the age group of 5 - 10 years ( 42.5% ) and females 24/40 ( 60% ) outnumbered males 16/40 ( 40% ) . there was no significant variation between the two groups in terms of age and gender . a positive family history was obtained in 18 of the 40 patients ( 45% ) . only three patients gave history of atopy , out of which 2 patients had eczema surrounding the lesions . most common site of occurrence was the face followed by chest and neck , which were involved in 22 , 9 , and 6 patients , respectively . at the end of this study , group a showed complete clearance of lesions in 10 ( 50% ) out of the 20 patients , with none showing clearance by 4 weeks , 2 patients showing complete clearance by 8 weeks and the rest by 12 weeks . group b showed total clearance of lesions in 17 ( 85% ) out of 20 patients , out of which 2 patients were cleared of lesions by 4 weeks , another 5 by the end of 8 weeks and 10 more patients by 12 weeks [ figure 1 ] . number of patients who showed complete disappearance of lesions initial distribution of number of lesions was statistically similar between two groups with p = 0.470 . a steady decline in the mean value of the lesions was noted in both the study groups throughout the follow - up period . the mean lesional count decreased from 7.20  3.381 standard deviation ( sd ) to 0.90  1.294 sd at the end of 12 weeks in patients treated with imquimod [ figure 24 ] . the comparison between the number of lesions at baseline and the number of lesions at week 12 was found to be statistically significant with p = 0.000 in group a patients . the mean lesional count decreased from 7.10  5.057 sd to 0.20  0.523 sd at the end of 12 weeks with 10% koh solution [ figure 57 ] . this reduction in the number of lesions at the end of 12 weeks was statistically significant p = 0.000 in group b patients . disappearance of lesions following treatment with imiquimod before and after treatment with imiquimod pigmentary disturbance seen following treatment with potassium hydroxide before and after treatment with potassium hydroxide overall , a better response was shown by patients who received koh as compared to those who received imiquimod , and the difference was statistically significant as p = 0.010 at 1 and 2 follow - up ; and p = 0.019 at the last follow - up [ table 1 ] . comparison of reduction in the lesional counts between the two groups five ( 25% ) of 20 patients receiving imiquimod developed new lesions whereas no new lesions were seen in those who received koh . of the 20 patients who received koh solution , 10 ( 50% ) showed adverse effects , whereas of the 20 patients who received imiquimod , only 4 ( 20% ) showed adverse effects . the result was significant statistically with p = 0.18 . the most common side effect observed after treatment with koh was pigmentary disturbances , 6 out of 20 patients showed hypopigmentation , whereas 4 showed hyperpigmentation and one patient showed ulceration [ figure 8 ] . five of these patients also complained of burning sensation . the most common adverse effect seen with imiquimod was erythema , ( 2 patients ) . a comparison of adverse effects seen in both the groups was highlighted in figure 9 . the faster onset of action and better efficacy of 10% koh can be ascribed to its potent tissue destructive ability whereas imiquimod acts by inducing cell mediated immunity , hence the delayed response . this can also explain the continued appearance of new lesions in patients receiving imiquimod and not koh as the early destruction caused by koh may prevent autoinoculation . at the end of 12 weeks , metkar et al . the authors found complete clearance of lesions in 8 ( 57% ) out of 14 patients with imiquimod , and 8 ( 42.1% ) out of 19 patients with koh . this is in contrast with the finding of our study . in the study by seo et al . , absolute clearance of lesions was seen in 8 ( 57% ) of 14 patients with imiquimod , and 10 ( 77% ) out of 13 patients with koh , which is in accordance with the sfindings of our study . this can be attributed to the fact that there was only one giant mc lesion in our study , the remaining being small lesions . in the study by mahajan et al . puri observed complete clearance of genital mc lesions in 27 ( 75% ) of the 36 patients with once daily application of 5% imiquimod . both the studies indicate that daily application of koh and imiquimod brings about better efficiency and at a faster rate . four ( 20% ) out of 20 patients receiving imiquimod showed adverse effects , with 2 showing erythema , 1 showing scaling and 1 showing hypopigmentation . in the study conducted by barba et al . this may be attributed to the daily application of imiquimod in this study , as opposed to thrice weekly in ours . mosher and lio reported febrile seizures and cytokine dermatitis with the use of imiquimod , which we did not come across . in those who received 10% koh , 10 ( 50% ) out of 20 patients showed adverse effects , 6 patients showed hyperpigmentation and 4 showed hypopigmentation , 5 of these patients complained of burning . ulceration with secondary infection , erythema , itching and scaling were seen in one patient each . parent of the patient who developed ulceration reported having applied excessive amounts of koh 10% hoping for a faster recovery . it was found that superficial ulceration could not be avoided even with brief careful application of koh by the parents . in the same study , 2 patients had to discontinue due to severe stinging . this could have occurred due to daily application of 20% koh in this study in contrast to thrice weekly application of 10% koh in our study . romiti et al . did a study on 5% koh in the treatment of mc and they found that it was tolerated well by children , the findings in the study by rajouria and co - workers further strengthened this view . thus , it can deduced that the unfavorable aftermath of koh can be reduced by using it in a lower concentration . in their comparative study , seo et al . observed adverse effects including erythema , ulceration , scaling and hyperpigmentation in 6 ( 46% ) out of 13 patients in the imiquimod group and 6 ( 42% ) out of 14 patients in the koh group . two patients in the imiquimod group and 1 in the koh group discontinued the treatment because they could not tolerate the local irritation . in the study conducted by metkar et al . , 15 ( 78.9% ) out of 19 on koh , whereas 10 ( 55.5% ) out of 18 patients on imiquimod developed adverse effects . systemic side effects of imiquimod were not seen and no patient discontinued the treatment due to adverse effects . both 5% imiquimod cream and 10% koh solution have turned out to be modalities that are safe , efficacious , and easily usable at home . in a resource poor country like ours , curettage would be the best option , but in the case of recurrence of lesions , children may not allow to repeat the procedure owing to pain and fear . in this scenario , judicious application of 10% koh solution seems to be prudent as it is inexpensive and efficient , albeit with a few minor adverse effects . if the parents can bear the cost without any serious detriment , then 5% imiquimod cream appears to be a better option as its adverse effects are almost negligible . further studies need to be done with respect to various concentrations of koh and a standardized mode of delivery of the drug . what 's new : 5% imiquimod cream , which has been used successfully in the treatment of genital warts , has proven its mettle in resolving lesions of mc . koh solution when used in the concentration of 10% is effective and safe in treating mc .
background : although molluscum contagiosum ( mc ) is a self - limiting condition , active therapy could prevent further spread and improve cosmesis . 
 most of the available treatment modalities traumatize the lesions and have to be undertaken in the hospital , therefore evoking panic in children . in the quest for an alternative therapy 
 , this study comparing 10% potassium hydroxide ( koh ) solution and 5% imiquimod cream was taken up.aims and objectives : to compare the efficacy and tolerability of 10% koh and 5% imiquimod in the treatment of mc.materials and methods : this comparative study was conducted over a period of 18 months from october 2011 to march 2013 , 40 patients between the age group of 1 - 18 years with clinically diagnosed mc were divided into two groups ( lottery method ) , 20 patients were treated with 5% imiquimod cream ( group a ) and the other 20 were treated with 10% koh solution ( group b ) . 
 patients were followed up on the 4th , 8th and 12th week of treatment.results:at the end of 12 weeks , out of 20 patients who received 10% koh , 17 patients showed complete disappearance , whereas out of 20 patients who received 5% imiquimod , only 10 patients showed total clearance of the lesions . 
 adverse events were more frequent with 10% koh , pigmentary disturbances being the most common.conclusion:with only minor adverse effects , 10% koh is an inexpensive and efficient modality for the treatment of mc in the pediatric age group . 
 although 5% imiquimod was effective in clearing the lesions with minimal adverse effects , the longer duration required for its efficacy may deter its wider use .