Molluscum contagiosum virus is an important human skin pathogen. It can cause disfigurement and suffering in children, in adults it is less common and often sexually transmitted. Several treatment options, medical as well as surgical, are available but none can be said to be ideal. Potassium hydroxide ranging from 2.5% to 20%6-17 has been found to be relatively cheap, painless, safe and effective treatment modality.The index study was undertaken to study the comparative efficacy and adverse effects of 5% and 10% KOH in patients with MC attending the Skin OPD at Geetanjali Medical College and Hospital, Udaipur.
During the study period of one year ranged from December 2016 to December 2017, a total of 38 patients attended the Skin OPD with an incidence 0.2%. However, worldwide incidence ranging from 2% to 8% has been documented. MC is considered to be more common during childhood, In our study majority of the patients were children belonging to the age group of 6-15 years ( 50.0%) followed by 16-25 years ( 26.3%) , < 5 years (15.8%) and < 26 years ( 7.9%). Males outnumbered females in our study ( M: F= 1.71:1). The same has been reported in some other studies too. However, no sex predilection has also been reported.
The mean number of lesions was 7.19; the number ranging from 1 to 27. In another study on 40 patients, the mean lesion count of 22.2 was reported; the number of lesions varying from 4 to 96.
The commonest site involved was face followed by upper limb, neck, genital, buttock , abdomen and back. Face as the commonest site affected has also been reported in a study while extra facial sites have reported to be more commonly involved in other studies. Urban patients (29; 76.3%) significantly outnumbered rural patients ( 9; 23.7%); the urban: rural ratio being 3.22:1. It may be due to easy access to a tertiary health care centre and better health awareness among urban subpopulation. Despite lesions being more common on the face and preponderance of urban patients, only 21.1% patients reported for treatment in less than one month. Majority (30; 78.9%) of the patients had not sought any treatment for MC. The delayed treatment seeking attitude could be due to asymptomatic and self limiting nature of the disease. Although MC is contagious, the family history was present in 1/6th patients only. However in one study, one third of siblings had MC reinforcing that infection is acquired by direct contact and via fomites.
In our study atopy was associated in 3 (7.9%) patients followed by trauma 3 ( 7.9%). In a Greek study a statistically significant association has been reported between MC and AD. Atopic dermatitis is said to be a predisposing factor for MC possibly due to impaired epidermal barrier and local cellular immunity. In another study from Quebec, AD was reported in 43.9% children with MC compared to 15% to 20% of their general population.
Topical therapy remains the mainstay of management approach for MC. Although many topical agents are available but the optimal treatment approach has not been determined yet. KOH used in various concentrations has been proved to be safe, painless and effective. In the index study the therapeutic efficacy of KOH was assessed in terms of reduction in mean lesion count, percentage reduction in number of lesions and complete clearance of lesions. The lesions decreased progressively and significantly with KOH 5% as well as 10%. A comparison between both solutions revealed that the percentage reduction was maximum with 10% KOH followed by 5% KOH.
Amongst the various studies available on this subject, there has not been any uniformity in the study design in terms of number of patients, strengths of KOH used , frequency and duration of application, follow up period and recurrence rate. Some of the studies using 10% KOH in MC have shown variable outcomes. In one of the pioneer study, 10% KOH was used twice daily in 35 patients until clearance of all the lesions. Of these, 32 patients completed the study and all achieved the complete clearance of lesions in a mean period of 30 days. In another study, 40 patients who applied 10% KOH twice daily achieved complete clearance of lesions in 37 (92.5%) patients after a mean period of 4 weeks. Handjani et al in a study on 15 patients reported complete clearance of lesions at the end of 4 weeks in 86.6%, partial response and no response in 6.7% each. Short et al in a double blind randomized placebo controlled study compared 10% KOH with normal saline ( placebo) and reported complete clearance in 7 of the 10 patients in an average time of 54 days. Metkar et al, in a study on 19 patients used 10 % KOH three day per week at night and observed total clearance of lesions in 8 (42.1%). Out of these 8 patients, 6 patients were cleared of lesions by 4 weeks and the other 2 patients by 8 weeks. The response to treatment was seen irrespective of duration of disease and site of involvement. Seo et al reported a complete clearance of lesions in 10 (77%) out of 13 patients. Of these, 6 were cleared of lesions by 4 weeks and the other 4 by 8 weeks.
In our study 10% KOH one daily application at bed time regularly for 8 weeks period showed complete clearance of lesions in 10 (52.6%) patients at the end of 8 weeks while 3 (15.7% ) patients showed complete clearance of lesions at 4 weeks. The reduction in mean lesion count occurred progressively from 8.16 ± 5.975 SD at baseline to 0.95 ± 1.311 SD .
A 5% KOH aqueous solution used twice a day for 6 weeks has also been shown to be as effective and less irritating when compared to the 10% KOH solution. In a study on 20 children, all children showed complete clearance of lesions within 6 weeks. In a study by Rajouria et al on 25 patients using 5% KOH every night, a decrease in mean lesion count from 9.48 ± 3.00 SD to 1.67 ± 0.58 SD at the end of 4 weeks was reported.
In our study 5 (26.3%) patients showed complete clearance of lesions at the end of 8 weeks period while 3 (15.7%) patients showed clearance at the end of 4 weeks. The analysis of mean lesion count in our study showed a reduction in the number of lesions from 6.63 ± 4.089 SD to 4.26± 4.175 SD at the end of 8 weeks. This was statistically significant.
Besides 10% and 5% KOH, 2.5 % KOH has also been used and compared with 5 % KOH. The study concluded 5% KOH was more effective than 2.5% KOH. In our study also it was observed that 10 % KOH fared better compared to 5% KOH with respect to all the three assessment parameters i.e. reduction in mean lesion count, percentage reduction in number of lesions and complete clearance of lesions, keeping the baseline pre-clinical parameters of two groups well matched initially.
In this study, a total of 24 adverse events were recorded . Maximum ( 17 ) events occurred at the site of 10% KOH application followed by 5% KOH ( 7 ). A similar observation was also been reported by Romiti et al, who found 5% KOH as effective and less irritating compared to 10% KOH.
The most frequent events were erythema, burning, pigmentation and crusting in that order.
However, crusting as a commonest adverse event followed by erythema and pigmentary changes has been observed in another indian study.