Condition category
Infections and Infestations
Date applied
Date assigned
Last edited
Prospectively registered
Overall trial status
Recruitment status
No longer recruiting
Publication status

Plain English Summary

Not provided at time of registration

Trial website

Contact information



Primary contact

Dr J.A.H. Eekhof


Contact details

Leiden University Medical Centre
P.O. Box 2088
2301 CB
+31 (0)71 527 5318

Additional identifiers

EudraCT number number

Protocol/serial number


Study information

Scientific title

Randomised controlled trial of the treatment of warts in general practice



Study hypothesis

The usual treatment for warts in Dutch general practice is cryotherapy with liquid nitrogen. More than 50% of all warts are treated with cryotherapy alone and in only 14% salicylic acid is used as mono-therapy.

The prestigious Cochrane review concludes that there is an urgent need for high-quality randomised controlled trials on the routine treatments for common warts, particularly cryotherapy. While there is convincing evidence for the efficacy of topical salicylic acid compared to placebo,

high quality studies in which cryotherapy and salicylic acid are compared to natural history are still lacking.

According to the Cochrane review the most urgent need is for a trial to compare topical salicylic acid, cryotherapy and placebo. Since the most recent amendment (May 2003) no new studies are published.

Ethics approval

Received from the local medical ethics committee

Study design

Multicentre, randomised controlled parallel group trial

Primary study design


Secondary study design

Randomised controlled trial

Trial setting

Not specified

Trial type


Patient information sheet


Warts (Verruca vulgaris)


Treatment arms:
For the treatment with cryotherapy we chose a high-intensity regimen: a 2-weekly consultation till the wart has disappeared (maximum 13 weeks), 3 applications of the same wart per session, each application until a frozen halo appears of 2 mm around its base.

For the local treatment with salicylic acid vaseline album (petrolatum) we used a once a day application of a concentration of 40% for warts on the sole of the feet and on other parts of the skin. We chose a concentration of 40% to offer patients a stronger therapy than the over-the-counter therapies (like Formule-W), which have a concentration of 17%. Covering the skin up with tape will protect the skin around the wart. Application will be continued till the wart has disappeared (maximum 13 weeks).

Patients who were randomised into the natural history arm will be informed about the high spontaneous cure rate. We refrained from a placebo-comparison because this insufficiently resembles daily practice. An expectantly awaiting group will in the intervention period reliably reflect patient behaviours, including seeking of additional therapy (ability to maintain the expectantly awaiting policy).

Intervention type



Not Specified

Drug names

Salicylic acid

Primary outcome measure

‘Cure', meaning that the wart(s) have totally disappeared (normal skin) at 13 weeks.

Secondary outcome measures

1. The number of warts that still exist at follow-up, irrespective of the extent of regression (because for a separate wart regression cannot be validly assessed)
2. The subjective hindrance caused by the warts as scored by the patient on a numerical rating scale (0 - 10)
3. The subjective hindrance caused by the treatment as scored by the patient on a seven point scale (during the treatment period this will be scored weekly in a booklet)
4. Pain and other adverse effects of the treatments (pain, new warts, scars, irritation of the skin, dermatitis discomfort, invalidation, time)
5. Subjective judgement of the effect of the treatment by the patient at follow-up
6. Subjective judgement of the effect of the treatment by the research nurse at follow-up
7. Referral to a dermatological department, assessed at 26 weeks
8. After three months of the intervention period, patients for whom the warts have not disappeared are free to switch therapy. In the follow-up period we will carefully register to which therapies patients have switched and also if, and after how long this therapy leads to total disappearance of the warts.
9. The consumption of co-interventions during the intervention period and thereafter will also be used as secondary endpoints

Overall trial start date


Overall trial end date


Reason abandoned (if study stopped)


Participant inclusion criteria

All patients from the age of 4 onward, who present themselves to their practice with one or more new warts of the type vulgaris on hands or feet will be included. New warts are warts which are presented for the first time in the general practice by patients who have had no general practice (or dermatological) treatment for warts in the past year. For all patients duration of presence of the warts and the previous treatment(s) will be registered.

Participant type


Age group



Not Specified

Target number of participants


Participant exclusion criteria

Immuno-incompetent patients and mosaic warts larger than 1 cm in diameter.

Recruitment start date


Recruitment end date



Countries of recruitment


Trial participating centre

Leiden University Medical Centre
2301 CB

Sponsor information


Sponsor not yet defined (The Netherlands)

Sponsor details


Sponsor type

Not defined



Funder type

Research organisation

Funder name

The Netherlands Organisation for Health Research and Development (ZonMw) (The Netherlands)

Alternative name(s)

Funding Body Type

Funding Body Subtype


Results and Publications

Publication and dissemination plan

Not provided at time of registration

Intention to publish date

Participant level data

Not provided at time of registration

Basic results (scientific)

Publication list

2010 results in:
2013 results in:

Publication citations

  1. Results

    Bruggink SC, Gussekloo J, Berger MY, Zaaijer K, Assendelft WJ, de Waal MW, Bavinck JN, Koes BW, Eekhof JA, Cryotherapy with liquid nitrogen versus topical salicylic acid application for cutaneous warts in primary care: randomized controlled trial., CMAJ, 2010, 182, 15, 1624-1630, doi: 10.1503/cmaj.092194.

  2. Results

    Bruggink SC, Gussekloo J, de Koning MN, Feltkamp MC, Bavinck JN, Quint WG, Assendelft WJ, Eekhof JA, HPV type in plantar warts influences natural course and treatment response: secondary analysis of a randomised controlled trial., J. Clin. Virol., 2013, 57, 3, 227-232, doi: 10.1016/j.jcv.2013.02.021.

Additional files

Editorial Notes