Witches and warts often have a starring role together in fairy tales, which creates the perception that warts are evil and ugly. The reality is that warts can affect anybody, are often harmless, painless and go away on their own.
Warts are contagious, non-cancerous growths, usually on hands and feet, which are caused by the human papillomavirus (HPV)1,2. They are passed on through direct contact with people who have warts or items they may have touched. Many people become self-conscious of warts, and will try anything to make them go away, read on to see if a freeze dry wart remover may be the solution!
Dr. Scholls®, Compound W® and Wartner® freeze dry wart removers are often seen on television and in ads. As a result, they are sought out by consumers as self-treatment for warts. These products contain dimethyl ether and propane (DMEP) and claim to remove warts by freezing the infected tissues 3. Variations of these products are also available in pharmacies and doctor offices and claim to have been in use for many years 4.
How do they work?
Freeze dry wart removal is also known as cryotherapy. Applying pressurized liquid nitrogen or DMEP to infected tissues causes rapid freezing which kills the infected tissue5. Cryotherapy doesn’t kill the virus directly but it destroys the infected tissue around it. The local irritation caused by the treatment is thought to trigger an immune response which then acts against the virus and may even heal warts in other sites 3.
The technique of administration, the freezing time and the length of time between treatments can vary from one product to another16. One course of treatment usually requires a contact time of 10 to 30 seconds, depending on the location of the wart and aggressiveness of treatment required5. Improvement can be seen within a week and complete removal of warts within a few weeks. Depending on the size, location and type of warts, as well as the product being used to treat them, more than one treatment may be required.
You will know the treatment is not effective if there doesn’t seem to be any benefit beyond a total of four treatments over the span of three months, especially for warts on hands and feet1.
What kinds of warts do they treat?
Freeze dry wart removal can treat two types of warts; common warts (Verruca vulgaris) and plantar warts (Verruca plantaris).
Common warts are mainly found on the back of hands and fingers, and can spread to other parts of the body by scratching or other skin traumas. Plantar warts mainly grow at pressure points (soles of feet) causing discomfort and in severe cases, pain 5.
Do they really work?
Though the treatment appears promising, most of the evidence is conflicting, making it difficult to judge. Regardless of the warts’ location, the combined cure rates of three studies comparing freezing warts to no treatment, show no advantage of freezing warts1. In other words, treating the wart with DMEP or leaving the wart alone results in the same cure rate.
When compared to salicylic acid (another agent), freezing with DMEP was equally as effective1. Whether you treat the wart with freeze dry wart removers or with salicylic acid, the cure rates are the same. However, without concrete and quality evidence on its effectiveness, experts are reluctant to consider freeze dry wart removal as first choice treatment 6.
It is important to note that in doctors’ offices, a typical course of liquid nitrogen involves temperatures of -196˚C (-321˚F), whereas most over-the-counter freeze dry wart removers contain dimethyl ether propane (DMEP), which is not nearly as effective. DMEP cannot reach temperatures as cold as liquid nitrogen, and if they did, it would be unsafe for consumers to buy over the counter4,11,12. As a result, the results of studies which used liquid nitrogen don’t apply to the use of over-the-counter freezing kits that use DMEP.
Keep in mind that factors such as person’s age, the state of the affected person’s immune system, location of the wart, form of the wart and how long it’s been presence, how well you apply to the procedure and application technique all affect how well a product will work 16.
Are freeze dry wart removers safe?
Freeze dry wart removers are well tolerated when used correctly and when applied to the affected area for the appropriate freezing time.
Common side effects of freezing warts include skin discomfort, pain, blistering where the treatment was applied, and scarring on darker skin tones 13. These side effects are greater for stronger treatment regimens1. For instance, you likely to experience pain if you use the product too frequently! Over using the product more will not cure of wart faster17.
Most freeze dry wart removers can be used for children four years and older. If irritation continues to last, it is best to talk with your pharmacist or physician for a change in treatment.
Some general safety tips:
- Do not use freeze away wart removers on birthmarks, moles or warts with hair growing from them 4.
- Be sure to avoid warts on the face, skin lining the nose and mouth, and in the genital area.
- To reduce the risk of further infection when treating hand warts, make sure hands are dry, unless pre-soaking is required.
- Apply clear nail polish around the site of the wart before applying the product to prevent side effects to the normal skin surrounding the wart.
Though most warts will be gone within two years, they are contagious, so cover them up to prevent spreading. Freeze dry wart removers are generally safe if you would like to use an over-the-counter product but keep in mind that not all warts can be self-treated. It costs around $30 for most over-the-counter products. If these products fail to treat your warts, then salicylic acid treatments, liquid nitrogen treatment or surgical removal of warts may be worth considering.
Chain Zhao, Sonia Ning, Julie Heung, Jamie Cheung, Seonghee Bark, Erica Nayoung Shin, B.Sc. Pharm Candidate(s)
Faculty of Pharmacy & Pharmaceutical Sciences
University of Alberta
Edited and Reviewed by The Health Aisle Team
- Kwok, C., Gibbs, S., Bennett, C., Holland, R., & Abbott, R. (2012). Topical treatments for cutaneous warts. The Cochrane Database Of Systematic Reviews, 9CD001781.doi:10.1002/14651858.CD001781.pub3
- Miller, P.F. (2013). Therapeutic Choices for Minor Ailments: Viral Skin Infections: Common and Flat Warts (1st ed.). Ottawa: Canadian Pharmacists Association
- Dawber, R.P.R., Colver, G.B., Pringle, F., & Jackson, A. (1997). Cutaneous Cryosurgery Principles and Clinical Practice (2nd ed.). London: Taylor & Francis Ltd.
- Pray, W.S., Pray, G.E., & Pray M. (2011). Removing warts with nonprescription treatments. US Pharmacist, 36(8), 15-23. Retrieved from http://www.uspharmacist.com/content/d/consult_your_pharmacist/c/29609/
- Dall’Oglio, F., D’Amico, V., Nasca, M. R., & Micali, G. (2012). Treatment of Cutaneous Warts: An Evidence-Based Review. American Journal Of Clinical Dermatology, 13(2), 73-96.
- Loo, S. K. F., & Tang, W. Y. M. (2009). Warts (non-genital). Clinical Evidence, (2009), 1-29.
- Cockayne, S., Hewitt, C., Hicks, K., Jayakody, S., Kang’ombe, A., Stamuli, E., & … Watt, I. (2011). Cryotherapy versus salicylic acid for the treatment of plantar warts (verrucae): a randomised controlled trial. BMJ (Clinical Research Ed.), 342d3271. doi:10.1136/bmj.d3271
- Bruggink, S., Gussekloo, J., Berger, M., Zaaijer, K., Assendelft, W., de Waal, M., & … Eekhof, J. (2010). Cryotherapy with liquid nitrogen versus topical salicylic acid application for cutaneous warts in primary care: randomized controlled trial. CMAJ: Canadian Medical Association Journal = Journal De L’association Medicale Canadienne, 182(15), 1624-1630. doi:10.1503/cmaj.092194
- Steele, K., & Irwin, W. (1988). Liquid nitrogen and salicylic/lactic acid paint in the treatment of cutaneous warts in general practice. The Journal Of The Royal College Of General Practitioners, 38(311), 256-258.
- Bunney, M., Nolan, M., & Williams, D. (1976). An assessment of methods of treating viral warts by comparative treatment trials based on a standard design. The British Journal Of Dermatology, 94(6), 667-679.
- Buckley, D. (2013). Cryosurgery for warts in general practice. Forum Journal, April, 43-45. Ireland: Retrieved from https://www.icgp.ie/assets/55/18F555CB-A5AF- 86A8-217DEB6A93943BCB_document/Dermatology.pdf
- DermNet NZ. (1997). Cryotherapy. Retrieved from http://dermnetnz.org/procedures/cryotherapy.html
- NHS. (n.d.). Warts & verrucas. (2012) Retrieved from http://www.nhs.uk/Conditions/Warts/Pages/Treatment.aspx
- Keogh-Brown, M.R., Fordham, R.J., Thomas, K.S., Bachmann, M.O., Holland, R.C., Avery, A.J., Armstrong, S.J., Chalmers, J.R., Howe, A., Rodgers, S., Williams, H.C., & Harvey, I.(2007). To freeze or not to freeze: a cost-effectiveness analysis of wart treatment. DERMATOLOGICAL SURGERY AND LASERS, 156(4), 691687-692. doi: DOI10.1111/j.1365-2133.2007.07768.
- Thomas, K.S., Keogh-Brown, M.R., Chalmers, J.R., Fordham, R.J., Holland, R.C., Armstrong, S.J., Bachmann, M.O., Howe, A.H., Rodgers, S., Avery, A.J., Harvey, I., & Williams, H.C.(2006). Effectiveness and cost-effectiveness of salicylic acid and cryotherapy for cutaneous warts. An economic decision model. Health Technology Assessment, 10(25).
- Lipke,M.M. (2006) An armamentarium of wart treatments. Clinical Medicine and Research, 4;4: 273-293.