Topical adapalene in the treatment of plantar warts; randomized comparative open trial in comparison with cryo-therapy.

BACKGROUND: Various therapeutic modalities, which are available for treating plantar wart, have not been successful every time. AIMS: To evaluate topical adapalene under occlusion in the treatment of plantar warts and compare it with cryo-therapy.
MATERIALS AND METHODS: 50 patients with 424 plantar warts were included in this single center, two arm, prospective, randomized, control, open study. Patients were allocated randomly into two groups consisting of 25 patients each. Group A patients having 299 plantar warts were treated using adapalene gel 0.1% under occlusion while Group B patients having 125 warts were treated using cryo-therapy. All the patients were evaluated weekly till the clearance of all the warts and the results compared. RESULT: All the warts of 25 patients of Group A that were treated using adapalene gel 0.1% cleared in 36.71 ± 19.24 (55.95-17.47) days except those in one patient. In Group B, warts in all except one treated by cryo-therapy cleared in 52.17 ± 30.06 (82.23-22.11) days. There were no side effects like scar formation, irritation, erythema, or infections with adapalene group while in the cryo group scar was seen in 2 patients, pain in 24, erythema in 10, and infection in 3 patients.
CONCLUSION: Adapalene gel 0.1% under occlusion is an effective, safe and easy to use treatment for plantar warts and may help clear lesions faster than cryo-therapy.

RCT Entities:   Population Interventions Outcomes

What was known?

Treatment result of plantar warts is not uniform.

Introduction

Treatment of plantar warts, which are caused by human papilloma virus (HPV) type 1, 2, and 4, is often challenging. Various therapeutic modalities that have been used for treating it have not been successful every time.[1234]

Adapalene, a synthetic naphthoic acid derivative, is very commonly used in the treatment of mild-to-moderate acne.[56] It is available as 0.1% aqueous gel. It is a retinoid with ability to alter keratinization and affinity for retinoic acid receptor (RARY).[7] It is found predominantly in the epidermis. It has been found to have anti-inflammatory action, inhibits cell proliferation, and modulates cell differentiation.[89] After successful treatment of 10 patients with a total 118 warts, with topical adapalene 0.1% gel, with occlusion,[10] subsequently we studied it in a larger number of patients in a prospective, randomized, control, open trial in comparison with cryo therapy. Data on 50 patients were randomly allocated into two groups, one group was treated with 0.1% adapalene gel under occlusion and the other group with cryo-therapy[11] are presented. Time taken to complete clearance of lesions was compared between the two groups.

Materials and Methods

Fifty patients with 424 plantar warts were included in this single center, two arm, prospective, randomized, control, and open study. Diagnosis of plantar warts was made based on clinical presentation like rough surface, well-defined border [Figure 1] and pain on pressure. Informed consent was taken from all the patients after explaining in details about the purpose and procedure of the treatment. Healthy patients with plantar warts were included in the study. Those patients who were on any systemic therapy in the past 8 weeks and pregnant women were excluded from the study. All topical treatment was stopped 4 weeks prior to the study. Patients were randomly allocated into two treatment groups: Group A (Adapalene 0.1% gel) and Group B (cryo- therapy, very commonly used therapy for plantar warts in this part of country). Comparison was not done with placebo due to fear that many patients may drop during follow-up due to ineffectiveness. All the odd numbered patients, who came to the outpatient department, were allocated to Group A, while all the even numbered patients were allocated to Group B. Thus, 25 patients who were allocated to Group A were treated with topical adapalene 0.1% gel applied twice daily under occlusion using plastic wrap while another 25 patients who were allocated to Group B were treated with cryo-therapy for1-2 minutes using N2O gas operated machine with −94°C temperature. Cryo-therapy was repeated within 2 weeks, if there were no signs of improvements in the form of reduction in the pain and/or development of black spots. Once there was improvement, they were followed up for clearance without any cryo sitting. In both the groups, hyperkeratosis or thick areas were pared before doing cryo-therapy or applying adapalene gel. Thus paring was done initially during treatment. The treatment was continued till the clearance of all the warts [Figure 2] in both the groups. The effect of treatment was evaluated weekly till the clearance of all the warts, followed by monthly evaluation for at least 6 months for any recurrences.

Figure 1

Plantar warts before treatment

Figure 2

Plantar warts after treatment

Statistical analysis

A test of significance using Student's t-test was employed to see the efficacy of both the treatments in terms of duration of clearance of warts. At 9 degrees of freedom and 5% level of significance it was found that there was a significant difference between both treatment regimes. On the basis of limited data, it was found that use of treatment regime of adapalene (0.1%) with occlusion has reduced duration of clearance of warts in these patients (P < 0.05).

Results

Fifty patients (M-26, F-24) with 424 warts were enrolled in this study. The mean age of all the patients was 27.56 (13-55) years and the mean duration of the warts was 8.31 months. One patient in each group was lost to follow-up. In Group A, all the warts in 24 patients disappeared in 36.71 ± 19.24 days [Table 1]. In Group B, all the warts in 24 patients disappeared in 52.17 ± 30.06 days [Table 2] in an average of 1.88 (1-4) sittings of cryo-therapy.

Table 1

Detail of patients treated by adapalene gel 0.1% under occlusion

Table 2

Detail of patients treated by cryo-therapy

There was no recurrence in any patient followed up for an average of 8.47 months.

On comparison of each group [Table 3], patients in Group A, treated with adapalene with occlusion, achieved complete clearance of their lesions sooner than patients in Group B, treated with cryo-therapy.

Table 3

Comparison of treatment by adapalene gel 0.1% and cryo-therapy

Side effects

There was no side effect like irritation, erythema, infection, or scar formation in any patient treated by adapalene gel. However, patients of the cryo group developed scar in 2 patients, pain in all 24 patients, erythema in 10 patients, and infection in 3 patients.

Discussion

Various immuno-modulating agents used for treatments of warts include oral cimetidine and levamisole,[1213] intralesional BCG vaccines, interferon, and imiquimod.[141516] The aim of using immuno-therapy is to hasten the clearance of warts although the mechanism is still not clear. One theory suggests induction of a type IV hypersensitivity reaction another suggesting that the substance acts as a hapten to wart virus proteins to induce an immune reaction to HPV.

In a comparative study by Parsad et al.[13] oral cimetidine was able to clear lesions in 11 weeks in 31.5% of cases only where as cimetidine + levamisole took 7.8 weeks. Imiquimod, another immuno-modulator, was reported to clear the plantar warts when used with occlusion in 12 weeks.[14] Gelmetti et al.[17] used etretinate 1 mg/kg/day orally, in 20 children, for 3 months with extensive warts. Sixteen children showed complete regression, without relapse, while in 4, lesions relapsed after initial regression. Choi et al.[18] used acitretin 0.5 mg/kg body weight/day orally for 3 months in an extensive and recalcitrant wart with complete clearance of the lesion. Euvrard et al.[19] were the first to use topical retinoid in warts, in a transplant recipient patient, with good result.

In the present study, use of topical adapalene aqueous gel 0.1% under occlusion resulted in complete clearance of 286 plantar warts in 24 patients in 36.71 ± 19.24 days while 124 warts in 24 patients treated with cryo-therapy took 52.17 ± 30.06 days (P < 0.05). Thus adapalene gel 0.1% under occlusion is more effective than cryo-therapy in the treatment of plantar warts. There are several advantages of using adapalene over cryo-therapy. Adapalene, besides clearing the warts fast, also has no side effects. It is simple and convenient to apply.

In conclusion, topical adapalene under occlusion seems to be an effective, simple, and convenient to apply and safe modality of therapy for treatment of plantar warts and may help clear wart lesions sooner when compared to cryo-therapy. However, with topical adapalene, the patient has to use plastic occlusion daily which may be messy and may not be liked by some patients. It also needs confirmation by further study by more workers as it is the first study of its kind.

What is new?

Adapalene a new compound is able to clear the plantar warts fast without any side effect.