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GPs winning MMR uptake battle



It's easy to get stuck in a rut treating the same minor ailments day-in, day-out.

In this series experts give an evidence-based update on what works. This week Dr Sam Gibbs advises on warts

Warts are frustrating for the following reasons:

• Despite the fact we are in the 21st century there is still no reliably effective treatment.

• Although they are harmless, patients do not like the idea of not treating them and will go to extraordinary lengths to get rid of them.

• Although they are self-limiting, patients find this very hard to accept and are often, understandably perhaps, unwilling to wait for natural immunity to clear them.

• Good-quality trial evidence for the effectiveness of commonly-used treatments is woefully lacking.

We carried out a systematic review of randomised controlled trials focusing on local (not systemic) treatments for ordinary warts1,2. So far 52 trials have been reviewed and most were of low quality in terms of scientific rigour. None the less some conclusions can be drawn (see table).

What works?

•Patients treated with placebo do quite well.

• Topical salicylic acid applied daily for two to three months appears to genuinely increase the likelihood of warts clearing.

What doesn't work?

• Evidence for the absolute effectiveness of cryotherapy is surprisingly lacking.

• There is reasonable evidence that salicylic acid (two trials3,4) and occlusion with duct tape (one trial5) are at least as effective as cryotherapy and possibly slightly better.

• A range of other more obscure, hazardous and expensive treatments such as intralesional bleomycin, 5-fluorouracil, photodynamic therapy, interferons, the pulsed dye laser and dinitrochlorobenzene (DNCB) were unearthed. Except for DNCB none of these appears to have any striking advantage over simpler and safer approaches like salicylic acid.

Cost -effectiveness

• Taking all the available evidence into account it seems difficult to defend an important place for cryotherapy.

• It would also seem difficult to improve on salicylic acid paints and duct tape.

The bottom line: what GPs should do

An evidence-based sequential approach to treating warts:

1 If acceptable, leave well alone and await spontaneous resolution. Warts can be filed down weekly to keep them out of the way on the hands and reduce pain on the soles.

2 Use salicylic acid paint or duct tape occlusion for at least three months.

3 Try cryotherapy, although there is no evidence that it is better than 1 and 2.

4 Either give up and keep the patient comfortable (as in 1) or consider alternative treatments such as DNCB if available.

Sam Gibbs is a general dermatologist, Ipswich Hospital NHS Trust, and a member of the Cochrane Skin Group

Key findings: systematic review of wart treatments

Bottom line conclusion

Most randomised trials of wart treatments are not done very well (total of 52 trials reviewed)

Placebo treatments work quite well (17 trials)

Salicylic acid does work (six trials vs placebo)

Cryotherapy does not appear to be any more effective than much simpler safer treatments

(a. two trials of salicylic acid vs cryotherapy)

(b. one trial of duct tape vs cryotherapy)

Evidence for the absolute effectiveness of cryotherapy is surprisingly lacking (two small trials with cryotherapy and control groups)

Of the other treatments best reserved for very resistant warts, topical sensitisers such as DNCB (and diphencyprone) look promising (two trials)

Basic data

39 trials (75%) classified as low quality, 10 trials as intermediate quality and only three as high quality

On average a cure rate of about 30% of patients after about 10 weeks

144/191 (75%) patients cured with salicylic acid compared with 89/185 (48%) with placebo

a. 96/155 (62%) cured with salicylic acid compared with 107/165 (65%) cured with cryotherapy

b. 22/30 (71%) patients cured with duct tape compared with 15/31 (46%) with cryotherapy

11/31 (35%) patients cured with cryotherapy compared with 13/38 (34%) with placebo cream or no treatment

32/40 (80%) patients cured with DNCB compared with 15/40 (38%) with placebo

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