Contact immunotherapy of resistant warts with diphenylcyclopropenone

Use of Contact Immunotherapy in the Treatment of Skin Diseases Other than Alopecia Areata

For decades, contact immunotherapy with dinitrochlorobenzene, diphencyprone, and squaric acid dibutylester has played an important role in both clinical practice and scientific research. It is listed as the first-line treatment for extensive alopecia areata and was more recently approved for melanoma treatment as an orphan drug in the USA. Moreover, owing to the relative low cost and safety, topical immunotherapy has also been used in many infectious, neoplastic, and inflammatory dermatological diseases. It is especially valuable in vulnerable groups, for cosmetic/pain sensitive areas, or for multiple lesions. In this review, we summarize the current evidence supporting the use of contact immunotherapy for treatment of skin diseases, from articles collected from PubMed database. Owing to space limitation and already numerous studies focusing on alopecia areata, we include only skin diseases other than alopecia areata. In addition to diseases that have been reported to be treated by contact immunotherapy, the hypothesized mechanism, prognosis prediction, efficacy, and safety of these topical agents are discussed.

Topical treatments for cutaneous warts

BACKGROUND

Viral warts are common and usually harmless but very troublesome. A very wide range of local treatments are used.

OBJECTIVES

To assess the effects of different local treatments for cutaneous, non-genital warts in healthy people.

SEARCH STRATEGY

We searched the Cochrane Skin Group Specialised Register (March 2005), the Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 1, 2005), MEDLINE (1966 to March 2005), EMBASE (1980 to March 2005) and a number of other biomedical databases. The references of all trials and selected review articles were also searched. In addition, we contacted pharmaceutical companies involved in local treatments for warts and experts in the field

SELECTION CRITERIA

Randomised controlled trials of local treatments for cutaneous non-genital viral warts in immunocompetent (healthy) people.

DATA COLLECTION AND ANALYSIS

Data was extracted and two authors independently selected the trials and assessed methodological quality.

MAIN RESULTS

Sixty trials were identified that fulfilled the criteria for inclusion. The evidence provided by these studies was generally weak due to poor methodology and reporting. In 21 trials with placebo groups that used participants as the unit of analysis, the average cure rate of placebo preparations was 27% (range 0 to 73%) after an average period of 15 weeks (range 4 to 24 weeks). The best available evidence was for simple topical treatments containing salicylic acid, which were clearly better than placebo. Data pooled from five placebo-controlled trials showed a cure rate of 117/160 (73%) compared with 78/162 (48%) in controls, which translates to a risk ratio of 1.60 (95% confidence interval 1.16 to 2.23), using a random effects model. Evidence for the absolute efficacy of cryotherapy was surprisingly lacking. Two trials comparing cryotherapy with salicylic acid and one comparing duct tape with cryotherapy showed no significant difference in efficacy. Evidence for the efficacy of the remaining treatments reviewed was limited.

AUTHORS' CONCLUSIONS

There is a considerable lack of evidence on which to base the rational use of topical treatments for common warts. The reviewed trials are highly variable in method and quality. Cure rates with placebo preparations are variable but nevertheless considerable. There is certainly evidence that simple topical treatments containing salicylic acid have a therapeutic effect. There is less evidence for the efficacy of cryotherapy, but reasonable evidence that it is only of equivalent efficacy to simpler and safer treatments. The benefits and risks of topical dinitrochlorobenzene and 5-fluorouracil, intralesional bleomycin and interferons, photodynamic therapy and other miscellaneous treatments remain to be determined.

Local treatments for cutaneous warts

BACKGROUND

Viral warts caused by the human papilloma virus represent one of the most common diseases of the skin. Any area of skin can be affected although the hands and feet are by far the commonest sites. A very wide range of local treatments are available.

OBJECTIVES

To assess the effects of different local treatments for cutaneous, non-genital warts in healthy people.

SEARCH STRATEGY

We searched the Cochrane Controlled Trials Register (January 2003), the Skin Group trials register (January 2003), MEDLINE (1966 to January 2003), EMBASE (1980 to January 2003) and a number of other key biomedical and health economics databases. In addition the cited references of all trials identified and key review articles were searched. Pharmaceutical companies involved in local treatments for warts and experts in the field were contacted. The most recent searches were carried

SELECTION CRITERIA

Randomised controlled trials of local treatments for cutaneous non-genital viral warts in immunocompetent human hosts were included.

DATA COLLECTION AND ANALYSIS

Study selection and assessment of methodological quality were carried out by two independent reviewers.

MAIN RESULTS

Fifty two trials were identified which fulfilled the criteria for inclusion in the review. The evidence provided by these studies was generally weak because of poor methodology and reporting. In 17 trials with placebo groups that used participants as the unit of analysis the average cure rate of placebo preparations was 30% (range 0 to 73%) after an average period of 10 weeks (range 4 to 24 weeks). The best available evidence was for simple topical treatments containing salicylic acid, which are clearly better than placebo. Data pooled from six placebo-controlled trials show a cure rate of 144/191 (75%) compared with 89/185 (48%) in controls, odds ratio 3.91 (95% confidence interval 2.40 to 6.36), random effects model. Most of the bigger trials of cryotherapy studied different regimens rather than comparing cryotherapy with other treatments or placebo. Pooled data from two small trials that included cryotherapy and placebo or no treatment, showed no significant difference in cure rates. In two trials comparing cryotherapy with salicylic acid and one comparing duct tape with cryotherapy no significant difference in efficacy was demonstrated. There was no consistent evidence for the effectiveness of intralesional bleomycin. Four studies, using warts rather than individuals as the unit of analysis, had widely varying results which could not be meaningfully pooled. There was some evidence for the efficacy of dinitrochlorobenzene, a potent contact sensitizer. Pooled data from two small studies comparing dinitrochlorobenzene with placebo showed cure rates of 32/40 (80%) and 15/40 (38%) respectively, odds ratio 6.67 (95% confidence interval 2.44 to 18.23), random effects model. Only limited evidence was found for the efficacy of topical 5-fluorouracil, intralesional interferons and photodynamic therapy.Bleomycin, dinitrochlorobenzene, 5-fluorouracil, interferons and photodynamic therapy are potentially hazardous or toxic treatments.

REVIEWER'S CONCLUSIONS

There is a considerable lack of evidence on which to base the rational use of the local treatments for common warts. The reviewed trials are highly variable in method and quality. Cure rates with placebo preparations are variable but nevertheless considerable. There is certainly evidence that simple topical treatments containing salicylic acid have a therapeutic effect. There is less evidence for the efficacy of cryotherapy and some evidence that it is only of equivalent efficacy to simpler, safer treatments. Dinitrochlorobenzene appears to be effective but there were no statistically significant differences when compared with the safer, simpler and cheaper topical treatments containing salicylic acid. The benefits and risks of 5-fluorouracil, bleomycin, interferons and photodynamic therapy remain to be determined.

The therapeutic use of topical contact sensitizers in benign dermatoses

Topical therapy using contact sensitizers has been practised since the 1960s to treat conditions associated with an altered immunological state. Dinitrochlorobenzene, squaric acid dibutyl ester and diphencyprone are most commonly employed in the therapy of alopecia areata and viral warts. Few dermatology departments in the U.K. provide such treatment. This systematic review discusses the various contact sensitizers used for topical immunotherapy, the methodology of treatment, factors influencing efficacy and likely adverse effects.