Warts are a common skin problem seen in clinic but accurate data on their prevalence and incidence is hard to come by. Of the limited published research, most has reported the frequency in schoolchildren as this group probably represents the highest number of cases (1-6). The prevalence reported within these was as high as 39% of schoolchildren aged between 4 and 12 years, with around 20% of these warts located on the plantar surface (2).
Beyond childhood, the research data on cutaneous wart prevalence in adults is hard to come by. Moreover, when one looks at the difficulties with prevalence studies, extracting accurate data is extremely challenging. The design of the study can affect the prevalence figures. For example, one questionnaire study asking patients to report any warts they had showed 40% of respondents who said they didn’t have them, but when examined by an expert were found to have them (4). Prevalence studies are often too small to estimate the true prevalence of disease and relate to one particular geographical area.
A recent paper (7) accepted for publication in the British Journal of Dermatology undertook a study investigating the prevalence of skin diseases across five European countries (Sweden, Italy, Portugal, The Netherlands and Germany). What makes this study interesting is that the data is compiled from a large, representative sample of the adult population (18-74 years) within these countries which adds validity to the work. To undertake this, they undertook face-to-face interviews with over 12 000 adults in the selected countries obtaining data on skin problems (current and previous). Particularly they were questioning about the common disorders namely contact dermatitis and eczema, psoriasis, warts, acne, urticaria, skin cancer, leg ulcers and vitiligo. Sampling was through the electoral register and was well adjusted with stratifications for age and gender.
The analysis of the data was interesting because it meant that the data could give a snapshot of those currently with warts and those who and reported having warts. The point prevalence was shown in this adult group to be around 7%. When this was looked at from a lifetime perspective, 41% of adults reported as having had warts in the past. Of all the conditions covered in the survey, warts were the most prevalent over a lifetime illustrating how common they are and this finding was corroborated in an earlier global survey of diseases (8). Moreover, 50% were self-diagnosed suggesting that self-treatment is a common option.
It is important to bear in mind that recall bias is a common downside to this type of study. For example, acne is a condition which is suspected to affect around 80% of the population – much higher than warts. However, being a condition, which is common in adolescence, it may not have been fully reported by respondents, as it may have been something long forgotten in the past. Despite this, the paper gives us an estimation of a common podiatric problem in the adult age group.
Paper:
Svensson, A., R. F. Ofenloch, M. Bruze, L. Naldi, S. Cazzaniga, P. Elsner, M. Goncalo, M. L. Schuttelaar and T. L. Diepgen "Prevalence of skin disease in a population based sample of adults out of five European countries." British Journal of Dermatology Accepted for publication
The full paper can be accessed here:
References
1. Williams HC, Pottier A, Strachan D. The descriptive epidemiology of warts in British schoolchildren. Br J Dermatol. 1993;128:504-11.
2. van Haalen FM, Bruggink SC, Gussekloo J, Assendelft WJJ, Eekhof JAH. Warts in primary schoolchildren: prevalence and relation with environmental factors. Br J Dermatol. 2009;161(1):148-52.
3. Massing AM, Epstein WL. Natural history of warts. A two-year study. Arch Dermatol. 1963;87:306-10.
4. Kilkenny, Erlin, Young, Marks. The prevalence of common skin conditions in Australian school students: 1. Common, plane and plantar viral warts. Br J Dermatol. 1998;138(5):840-5.
5. de Koning MNC, Quint KD, Bruggink SC, Gussekloo J, Bouwes Bavinck JN, Feltkamp MCW, et al. High prevalence of cutaneous warts in elementary school children and the ubiquitous presence of wart-associated human papillomavirus on clinically normal skin. Br J Dermatol. 2015;172(1):196-201.
6. Bruggink SC, Eekhof JA, Egberts PF, van Blijswijk SC, Assendelft WJ, Gussekloo J. Natural course of cutaneous warts among primary schoolchildren: a prospective cohort study. Ann Fam Med. 2013;11(5):437-41.
7. Svensson A, Ofenloch RF, Bruze M, Naldi L, Cazzaniga S, Elsner P, et al. Prevalence of skin disease in a population based sample of adults out of five European countries. Br J Dermatol.n/a-n/a.
8. Hay RJ, Johns NE, Williams HC, Bolliger IW, Dellavalle RP, Margolis DJ, et al. The Global Burden of Skin Disease in 2010: An Analysis of the Prevalence and Impact of Skin Conditions. J Invest Dermatol. 2014;134(6):1527-34.