|Year : 2016 | Volume
| Issue : 6 | Page : 634-639
|Comparative evaluation of topical 10% potassium hydroxide and 30% trichloroacetic acid in the treatment of plane warts
Sandhaya Jayaprasad1, Radhakrishnan Subramaniyan1, Shalini Devgan2
1 Department of Dermatology, Command Hospital Air Force, Bengaluru, Karnataka, India
2 Department of Community Medicine, Guru Gobind Singh Medical College and Hospital, Faridkot, Punjab, India
|Date of Web Publication||9-Nov-2016|
Department of Dermatology, Command Hospital Air Force, Bengaluru - 560 007, Karnataka
Source of Support: None, Conflict of Interest: None
| Abstract|| |
Background: Warts are benign proliferations of skin and mucosa caused by the human papillomavirus (HPV). Plane warts are caused by HPV types 3, 10, 28, and 41, occurring mostly in children and young adults. Among the treatment modalities, topical application of trichloroacetic acid (TCA) is age old. Potassium hydroxide (KOH) has a keratolytic effect on virus-infected cells. It is less irritating, less painful, less scar forming, and can be safely used in children too. Hence, it could be a better topical agent in the treatment of plane warts. Aims and Objectives: To compare the safety and efficacy of topical 10% KOH with 30% TCA in the treatment of plane warts. Materials and Methods: Sixty consecutive patients with plane warts were randomly assigned into two arms of thirty patients each; arm A received topical 10% KOH and arm B received topical 30% TCA as a once weekly application until the complete clearance of warts or a maximum period of 12 weeks. Results: Statistically no significant difference (P = 0.07) was found between the objective therapeutic response to 10% KOH and 30% TCA at the end of study (12 weeks). However, subjective response to 10% KOH was better and statistically significant (P = 0.03). There was no recurrence of warts seen on follow-up for 3 months of complete responders in both the arms. Conclusion: 10% KOH is found to be equally effective in the treatment of plane warts compared to 30% TCA with the advantage of faster onset of action and tendency of completely clearing warts with fewer side effects.
Keywords: Plane warts, potassium hydroxide, trichloroacetic acid
|How to cite this article:|
Jayaprasad S, Subramaniyan R, Devgan S. Comparative evaluation of topical 10% potassium hydroxide and 30% trichloroacetic acid in the treatment of plane warts. Indian J Dermatol 2016;61:634-9
|How to cite this URL:|
Jayaprasad S, Subramaniyan R, Devgan S. Comparative evaluation of topical 10% potassium hydroxide and 30% trichloroacetic acid in the treatment of plane warts. Indian J Dermatol [serial online] 2016 [cited 2020 May 25];61:634-9. Available from: http://www.e-ijd.org/text.asp?2016/61/6/634/193670
What was known?
- Among many treatments available for plane warts, 30% trichloroacetic acid (TCA) is age old
- 10% potassium hydroxide (KOH) has been used for molluscum contagiosum, male genital warts and has also shown a good response in plane warts according to a few studies
- There is no Indian study comparing the efficacy of 30% TCA and 10% KOH in plane warts.
| Introduction|| |
Warts are caused by infection of keratinocytes by human papillomavirus (HPV). The incidence increases during childhood to reach a peak in adolescence and early adulthood then declines rapidly through the 20s and more gradually thereafter.  Verruca plana or plane warts are caused by HPV types 3, 10, 28, and 41, occurring mostly in children and young adults. Sites of predilection are the face, back of hands, and the shins. They are 2-4 mm flat-topped papules and are erythematous or brown-colored on pale skin and hypopigmented on darker skin.  They have the tendency to koebnerize forming linear, slightly raised papular lesions, especially in children. 
There are many modalities of treatment for the treatment of plane warts that includes topical salicylic acid, glycolic acid, 5-fluorouracil, isotretinoin gel, topical zinc sulfate solution, 50% citric acid, trichloroacetic acid (TCA), bacillus Calmette-Guérin immunotherapy, curettage/electrodessication, and cryotherapy. ,,,, Most treatments focus primarily on the destruction or removal of visible lesions or on the induction of cytotoxicity against the infected cell.
TCA is a topical destructive agent and causes hydrolysis of cellular proteins leading to cell death. It is effective in treating common, cervical, genital, and anal warts in the concentrations of 70-80% and has response rates comparable to cryotherapy. , Low concentrations (10-30%) are used for the treatment of common warts and superficial peeling.  The advantage is the complete lack of systemic toxicity. However, a few local effects such as pain, burning, hyperpigmentation, and rarely scar formation may occur.
Potassium hydroxide (KOH) is a strong metallic base used in the diagnosis of fungal infections, whiff test for bacterial vaginosis, treatment of male genital warts, and the treatment of molluscum contagiosum in children. ,,, KOH acts by its keratolytic effects that lead to the destruction of virus-infected cells causing resolution of warts. It is less irritating, less painful, less scar forming, and can be safely used in children too. Rarely, side effects such as itching, erythema, and dyspigmentation may be seen. KOH holds better promise for the treatment of warts according to a few studies.  Hence, it was felt worthwhile exploring this agent for the treatment of plane warts.
| Materials and Methods|| |
A single center, randomized, uncontrolled, open comparative therapeutic trial was conducted at the Department of Dermatology, Venereology and Leprosy at Command Hospital Airforce Bengaluru during the period from October 2013 to March 2015. A total of sixty consecutive patients of multiple cutaneous plane warts ranging from 3 to 50 in number anywhere on the skin except mucosa and genitalia of age more than 4 years of both sexes attending the outpatient department were included in the study. Pregnant and nursing women, patients with hypersensitivity to KOH or TCA, patients currently using any treatment for warts or having used any other treatment for warts within the last 1 month, with comorbid conditions such as diabetes or immunosuppression and those unable to return for follow-up were excluded from the study.
Patients were randomized into two arms of thirty each and matched with respect to age and sex. A systematic random procedure was chosen to select the patients for both arms. Every even patient was put into arm A and the remaining patients were included in arm B. Informed consent was taken and ethical clearance obtained from the Hospital Ethical Committee. The diagnosis of plane warts was made clinically with special attention to the morphology of lesions and loss of skin markings over the lesions. Location, size (measured using Schirmers tape), and number of warts were recorded on inclusion. In case of multiple warts, the average size of all the warts was calculated for assessing response.
Arm A received 10% KOH and arm B received 30% TCA topical application once weekly by the physician. In both groups, a cotton-tipped toothpick dipped in the solution was applied once to the wart under vaseline cover of surrounding skin, keeping it perpendicular to the skin surface. The patient was observed for 15 min for any side effects. The therapy was continued until the completion of 12 weeks or till all the lesions cleared, whichever was earlier. Both the groups were examined at the end of 4 weeks, 8 weeks, and 12 weeks to evaluate the response to treatment and for any side effects. Clinical resolution of the warts was determined by objective and subjective responses.
Evaluation of treatment response
Based on physician's perception of overall percentage of resolution of warts, patients were classified as complete responders: Complete disappearance (100%) of all the warts both in size and number, and partial responders who were in turn classified as moderate responders: More than 50% (51-99.9%) reduction in number and size of warts, mild responders: <50% (1-50%) reduction in number and size of the warts (average reading taken for both size and number) or nonresponders: No reduction (0%) in the number or size of warts.
The subjective response was noted as patients' perception of improvement as excellent, good, satisfactory, or poor. Results were analyzed statistically using Chi-square test.
| Results|| |
Of a total of sixty patients enrolled, 2 patients from arm A developed irritant contact dermatitis to KOH, and 1 patient was lost to follow-up. Three patients from arm B were lost to follow-up. A total of 54 patients (27 in each arm) were finally assessed at 12 weeks. Thirty-one (57.40%) patients were males and 23 (42.59%) were females. Age of the patients ranged from 6 years to 78 years, duration of warts from 2 months to 5 years, number of warts varied from 3 to 50, and size ranged between 1 and 10 mm. Thirty-six (66.66%) patients had warts over the face (18 patients each in arm A and B), 12 patients (22.22%) on the dorsum of hands (8 patients in arm A and 4 in arm B), 2 patients (3.70%) on the feet (arm A), 9 patients (16.66%) over the arms and legs (3 in arm A and 6 in arm B), and 1 patient (1.85%) over other sites (chest). In arm A (10% KOH), 15 (55.55%) were males and 12 (44.44%) were females. The mean age of patients was 28.86 years with standard deviation (SD) ±14.13. The mean duration of warts was 1 year. An average number of lesions were 16.19, and average size of the lesion was 3.19 mm. In arm B (30% TCA), 16 (59.25%) were males and 11 (40.74%) were females. The mean age of patients was 29.06 years with SD ± 10.37. The mean duration of warts was 9 months. An average number of lesions was 19.04, and the average size was 3.39 mm. Both the arms were comparable with respect to different independent variables including sex, age, number, size, and duration of lesions (P > 0.05). No patient had any comorbidities or any state of immunosuppression.
Study results at 12 weeks showed that in arm A (10% KOH), 7 patients (25.92%) had complete response, 13 patients (48.18%) had moderate response, 7 patients (25.92%) had a mild response, and none had no response. In arm B (30% TCA), 3 patients (11.11%) showed complete response, 8 patients (29.62%) had moderate response, 10 patients (37.03%) had mild response, and 6 patients (22.22%) had no response. Statistically no significant difference was found between the therapeutic response to 10% KOH and 30% TCA (P = 0.07) [Table 1]. However, it was noticed that the percentage of patients showing complete clearance (100% response) was more in arm A (10% KOH) which was 25.92% as compared to 11.11% in arm B (30% TCA) but no statistical significance was found. On analysis, the average percentage reduction in size and number of warts separately in two arms showed statistically significant results (P < 0.01) at the end of 4 th and 8 th week but at the end of the study, i.e., 12 th week, the difference in two arms was not statistically significant [Table 2] and [Table 3].
|Table 2: Distribution of subjects according to average percentage reduction of wart size in arm A (10% potassium hydroxide) and arm B (30% trichloroacetic acid) |
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|Table 3: Distribution of subjects according to average percentage reduction of wart number in arm A (10% potassium hydroxide) and arm B (30% trichloroacetic acid) |
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Results also showed that 10% KOH had a better response on warts of size 1-5 mm (P < 0.05), warts with numbers between 1 and 10 (P < 0.05) and warts of 2 months to 9 months duration (P < 0.05) as compared to 30% TCA. Results were statistically significant. However, on comparison of the response in the two arms based on the site of warts and age of patients, no statistical difference was observed (P > 0.05). Interestingly, subjective response to 10% KOH was better, and results were statistically significant (P = 0.03) [Table 4].
Erythema was seen in 3 patients (11.11%) in arm A during the procedure which disappeared within 10-15 min. Twenty-five patients (46.29%) experienced burning or itching sensation for a transient period of 10 min (arm A 7 patients/25.92% and arm B 18 patients/66.6%). Dyspigmentation was seen in 16 patients (29.62%) which included hypo/depigmentation in 6 patients (22.2%) in arm A and hyperpigmentation seen in 16 patients (59.25%) in arm B. Treatment in 2 patients in arm A (10% KOH) had to be discontinued due to irritant contact dermatitis to KOH [Table 5]. On follow-up of the patients with complete response after 3 months, no recurrence of warts was noticed.
|Table 5: Distribution of subjects according to side effects of treatment |
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| Discussion|| |
A multitude of therapies is available for the treatment of common warts with varying degrees of success ranging from the age-old destructive treatment to cryotherapy and the newly emerging therapies such as pulsed dye laser, intralesional immunotherapy, and autoinoculation therapy. ,, However, studies done on plane warts are scarce. We could not find a single published study on plane warts done in India. There are insufficient data available to show the efficacy and strength of recommendation for topical destructive or caustic agents which are safer, inexpensive, and easy to use in case of plane warts. This study has compared the efficacy of such two well-known agents, 10% KOH, and 30% TCA in the treatment of plane warts.
It was noticed that the average percentage reduction in wart size and number at the end of 4 th and 8 th week was better with 10% KOH which was statistically significant (P < 0.01) indicating that 10% KOH has a tendency of clearing the warts early, i.e., <8 weeks, whereas 30% TCA takes more time for the effect to occur and clearance rates seem to be less. However, at the end of 12 th week, both the agents did not show any statistical difference (P = 0.07).
Ten per cent KOH had a better response on warts of size 1-5 mm, warts with numbers between 1 and 10, and warts of duration 2-9 months as compared to 30% TCA. Results were statistically significant in these variables.
It was found that warts over the face showed a tendency of complete clearance compared to other sites such as hands, arms, and feet in both the arms [Figure 1] and [Figure 2]. However, 30% TCA showed postinflammatory hyperpigmentation which makes it slightly unfavorable in treating plane warts on face.
|Figure 1: (a) Plane warts on the forehead before treatment. (b) Complete resolution of warts on the forehead at 8 weeks with 10% potassium hydroxide|
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|Figure 2: (a) Plane warts on the right ear and preauricular region before treatment. (b) Complete resolution of warts at 12 weeks with 30% trichloroacetic acid|
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In a study done by Al-Hamdi and Al-Rahmani  comparing the effect of 5% and 10% KOH on plane warts with once daily night application for 4 weeks, 80.3% of Group A patients (5% KOH) showed complete response in comparison with 82.1% of Group B (10% KOH) patients. Nearly 14.7% showed partial response and 3.15% showed no response in 10% KOH group. The difference in the cure rate for patients showing complete disappearance was not statistically significant at the end of therapy (P = 0.439). However, topical 5% KOH solution showed a slower action in comparison with 10% KOH solution. In addition, the recurrence rates of warts among patients showing complete response were 5.8% in Group A versus 5.1% in Group B. Al-Hamdi and Al-Rahmani  used KOH solution as daily application for 4 weeks, whereas in this study, once weekly application was done. In addition, all the warts in the study by Al-Hamdi and Al-Rahmani were located on the face. That could have been the reason for better clearance rate. This study did not show any recurrence after 3 months of follow-up.
In another single-blinded clinical trial done by Pezeshkpoor et al.,  62 patients with common warts were randomly divided into two groups and were applied 80% TCA (Group A) and 35% TCA (Group B) once per week until complete clearance of the lesions or for a maximum duration of 6 weeks. Results showed statistically significant difference in improvement between the two treatment groups (P = 0.017). Improvement was greater with a higher concentration of TCA solution (80% TCA).
Results showed that 35% TCA had a lower clearance rate seen at the end of 6 weeks (12%) which is almost similar to this study (11.11%) at the end of 12 weeks. It can be interpreted that more time is probably needed for TCA to show complete response or higher concentration (>35%) can be tried. Review of literature shows that TCA in higher concentration (60-80%) has equal cure rates in genital warts compared to cryotherapy.  The British Association of Dermatologists guidelines suggests 50-80% TCA weekly application for 8 weeks for treating hand warts.  As there are no case-control or cohort studies of TCA in plane warts available, a few more studies are needed in future to compare the efficacy of different concentration of TCA in plane warts.
Comparing the safety profile of the two agents in our study, itching and burning was seen more in arm B (18 patients/66.6%) than arm A (7 patients/25.92%) during the procedure which was transient. Hypo/depigmentation was seen in 6 patients (22.2%) in arm A, and hyperpigmentation seen in 16 patients (59.25%) in arm B. TCA is known to cause burning and irritation when used in a concentration of >30% in all the dermatoses treated, but as the maximum frequency of plane warts occurs on the face, we took special precautions to prevent/reduce the side effects using ice cubes, especially in children. Hyperpigmentation is a known side effect of TCA, which makes it unfavorable in few skin Types III and IV and the female sex. Treatment in 2 patients in arm A (10% KOH) had to be discontinued due to irritant contact dermatitis after first application. No scarring was seen in either of the groups.
| Conclusion|| |
This study has shown that 10% KOH solution is as effective as 30% TCA in treating plane warts. Ten per cent KOH has the advantage of faster onset of action and tendency of completely clearing the warts with fewer side effects. In addition, plane warts of size 1-5 mm, <10 in number, and of few months duration (2-9 months) have shown a very good response with 10% KOH. On the other hand, 30% TCA has a slower onset of action and wart clearance takes more time. It is possible that a higher concentration of the agent may be needed to achieve an early response but will be limited by the greater chance of side effects. A few more studies are needed in future to compare the efficacy of different concentration of TCA in plane warts.
Both the agents are less expensive, easy to apply, and well suited for the self-treatment of plane warts by the patients. Hyperpigmentation seen with 30% TCA may make it less promising in the treatment of plane warts over the face in young females. About 10% KOH can be considered as an effective, safe, cosmetically acceptable, and first line therapy for plane warts in immune competent individuals.
Limitations of the study
The sample size was small to compare the results of both the agents in a common condition. Bigger cohorts would have given more accurate results. Both the agents could have been used twice weekly rather than once weekly for better results.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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What is new?
- This is one of the first Indian studies comparing topical 10% potassium hydroxide (KOH) and 30% trichloroacetic acid (TCA) in the treatment of plane warts
- Topical 10% KOH is as effective as topical 30% TCA in plane warts
- With the advantage of its faster onset of action, complete clearance of warts and lesser side effects in comparison to 30% TCA, 10% KOH can be effectively used as a topical agent with promising results.
[Figure 1], [Figure 2]
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5]
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