Condition category
Skin and Connective Tissue Diseases
Date applied
Date assigned
Last edited
Prospectively registered
Overall trial status
Recruitment status
No longer recruiting

Plain English Summary

Not provided at time of registration

Trial website

Contact information



Primary contact

Prof Wesley Vernon


Contact details

Podiatry Services
Jordanthorpe Health Centre
1 Dyche Close
S8 8DJ
United Kingdom
+44 (0)114 2371183

Additional identifiers

EudraCT number number

Protocol/serial number

Protocol Version 3 - December 2008

Study information

Scientific title

The long-term effectiveness of 40% salicylic acid plasters on corns: a prospective pragmatic parallel-group randomised controlled trial


Study hypothesis

Null hypothesis: there is no difference in clinical and patient-centred outcomes in treatment of corns between use of corn plasters and usual treatment.

Ethics approval

Not provided at time of registration

Study design

Prospective pragmatic parallel-group randomised controlled trial with equal randomisation

Primary study design


Secondary study design

Randomised controlled trial

Trial setting


Trial type


Patient information sheet

Not available in web format, please use the contact details below to request a patient information sheet


Corns occuring on the foot


308 participants will be recruited, 154 in each arm. One arm will receive 40% salicylic acid corn plaster treatment, the other usual 'scalpel' treatment. All study participants will be asked to describe the amount of pain experienced from the lesion at each visit using a visual analogue scale (VAS), whether they are satisfied with the treatment they are receiving using a simple questionnaire with pre-coded responses, to complete the Foot Disability Questionnaire and the Euro Quality of Life (EQ5D) instrument. These will be completed at each 3-monthly appointment and administered by the independent podiatrist (rater).

Patients in the corn plaster arm will then have the area cleared and a plaster applied and advised to keep on until the next visit 5 - 7 days later. On return, the plaster is removed and if the corn is loose, removal can be facilitated with blunt dissection. The plaster will be re-applied if the corn is still present and reviewed weekly for up to 4 weeks from initial treatment, with a plaster applied at each visit if the corn is still present.

The size of the corn (if still present) will be documented at 3-monthly intervals for up to 12 months after initial treatment by an independent podiatrist blind to the initial treatment allocation. If the corn has resolved, this will be checked at each visit and documented. Patients in the scalpel treatment arm will have the corn removed with a scalpel at the initial treatment and then reviewed at 3-monthly intervals for 12 months where the size of the corn with be recorded if still present, with removal of the corn carried out at each appointment if required.

Any dissatisfaction with either treatment or complications will be recorded at each visit. In the event of an adverse reaction (development of infection, or unbearable pain), subjects will be provided with the appropriate podiatry care to alleviate symptoms but follow-up data will still be collected unless the participant withdraws their consent. Anyone in the corn plaster group whose corn re-occurs after initial monthly corn plaster treatment will receive usual scalpel treatment at 3-monthly intervals and this data will be included in the analysis under the intention to treat principle.

Participating podiatrists will be asked to complete a short questionnaire to assess their view of the two treatments at the end of the study.

Intervention type



Not Applicable

Drug names

Salicylic acid

Primary outcome measures

Presence at 3 months post-randomisation of an unhealed or recurrent corn that requires further ongoing treatment.

Secondary outcome measures

1. Presence of unhealed or recurrent corns at 12 months
2. Mean Visual Analogue Scale (VAS) pain score at 3, 6, 9 and 12 months
3. Foot pain disability scores at 3, 6, 9 and 12 months
4. Cost-effectiveness of corn plaster compared with usual care
5. Podiatrist satisfaction with the two treatments at 12 months
6. Patient satisfaction at 3, 6, 9 and 12 months

Overall trial start date


Overall trial end date


Reason abandoned


Participant inclusion criteria

1. Adult patients (male and female subjects aged 18 years and older) with corns
2. Patients who are willing to take part for the duration of the study
3. Patients who have the capacity to make an informed decision and give informed consent

Participant type


Age group




Target number of participants


Participant exclusion criteria

1. Diabetes
2. Impaired circulation (including peripheral vascular disease, ischaemia)
3. A history of foot ulceration
4. Rheumatoid arthritis
5. Taking oral steroid medication
6. Dermatological conditions
7. Allergies to zinc oxide plaster
8. Allergies to salicylic acid
9. Neuropathy
10. Completely unable to reach their feet
11. Callus only and no corns
12. Infected corns or neurovascular corns
13. Pregnant or breast feeding
14. Peanut or soya allergy

Recruitment start date


Recruitment end date



Countries of recruitment

United Kingdom

Trial participating centre

Jordanthorpe Health Centre
S8 8DJ
United Kingdom

Sponsor information


Sheffield Health and Social Research Consortium (UK)

Sponsor details

c/o Dr Robert Dixon
Fulwood House
Old Fulwood Road
S10 3TH
United Kingdom
+44 (0)114 2718804

Sponsor type




Funder type


Funder name

National Institute for Health Research (NIHR) (UK) - Research for Patient Benefit (RfPB) programme (ref: 2008-005313-21)

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

Results - basic reporting

Publication summary

2013 results in:
2015 results in:

Publication citations

  1. Results

    Farndon LJ, Vernon W, Walters SJ, Dixon S, Bradburn M, Concannon M, Potter J, The effectiveness of salicylic acid plasters compared with 'usual' scalpel debridement of corns: a randomised controlled trial., J Foot Ankle Res, 2013, 6, 1, 40, doi: 10.1186/1757-1146-6-40.

  2. Results

    L Farndon, M Concannon, J Stephenson, A survey to investigate the association of pain, foot disability and quality of life with corns, J Foot Ankle Res., 2015, 8, 70, doi: 10.1186/s13047-015-0131-4.

Additional files

Editorial Notes