Self-reported prevalence of warts in children and GP consultation

Introduction

Cutaneous warts, caused by the human papillomavirus, appear commonly in children. Depending on their location, they can cause complaints [1], [2].

Currently, limited information about the epidemiology of warts in children in the population is available. The prevalence among schoolchildren varies from 2 to 20% [3]. Only a small proportion of children with sufficient complaints have parents that seek professional medical help. These patients represent the “tip of the iceberg” [4]. No data about the “shape” of the iceberg of patients infected with warts in the Netherlands have been previously available.

The present study aimed to assess the self-reported prevalence of warts in children aged 0–17 years and what proportion of these children consulted the general practitioner (GP) for warts.

Methods

We used additional health interview data of all children aged 0–17 years from the second Dutch national survey of general practice, performed by the Netherlands Institute for Health Services Research (NIVEL) in 2001. One hundred and ninety-five GPs in 104 practices registered data concerning all physician–patient contacts over a 12-month period. Patients were invited to participate in a health interview (response rate 65%) after they were selected randomly (5% sample) from the list of the participating GPs. One of the questions in the interview was whether the participants had suffered from warts in the previous 14 days before the interview. For further details about the second Dutch national survey, we refer to the article by Westert et al. [5].

Ethical approval

The study was carried out according to Dutch legislation on privacy.

Data analysis

Self-reported prevalence was stratified for socio-demographic characteristics. Among the children with warts, we assessed the proportion who consulted the GP for their warts, the so-called “helpseekers”, and those who did not consult the GP for their warts, the so-called “non-helpseekers”. We defined helpseekers as those who reported suffering from warts and consulted their GP within 14 days before and 3 months after the interview, and in whom the GP made the diagnosis of warts or the diagnosis of another skin disease that may be confused with warts by the lay public (see Appendix). Differences between helpseekers and non-helpseekers were assessed at a significance level of 5% using the Pearson chi-square test.

Results

Self-reported prevalence of warts and help seeking

In total, 2847 children aged 0–17 years were interviewed about their health status; of these, 176 (6.2%) reported suffering from warts. Within a time window of 14 days before and 3 months after the health interview, 41 of the 176 children (23.3%) sought medical help and the GP diagnosed warts or gave a warts-like diagnosis. In only 20 (11.4%) of the 176 children did the GP made the diagnosis warts. We repeated this analysis for different time windows and found highly similar results.

Table I shows the distribution of the self-reported prevalence of warts during the previous 2 weeks, stratified for socio-demographic characteristics. The highest prevalence was found in the age categories 5–9 and 10–14 years. Infants (<1 year) did not suffer from warts. Table I also shows a comparison in socio-demographic characteristics of helpseekers versus non-helpseekers; there were no differences between these two groups.

Table I.  Prevalence of warts among 2847 children aged 0–17 years in the population during 2 weeks, and socio-demographic characteristics of medical helpseekers versus non-helpseekers.

	Self-reported prevalence,% (n0=176)	95% confidence intervals,%	Helpseekers,% (n1=41)	Non-helpseekers,% (n2=135)	p value
Age categories, years
< 1	0	0	0	0	0.646
1–4	3.7	2.4–5.5	17.1	14.1
5–9	8.4	6.6–10.6	46.3	40.0
10–14	7.2	5.5–9.2	29.3	37.0
15–17	3.7	2.1–6.1	7.3	8.9
Total	6.2	5.3–7.2	100	100
Gender
Boys	5.9	4.7–7.3	46.3	48.9	0.941
Girls	6.5	5.2–8.0	53.7	51.1
Urbanization
< 30 000	5.3	4.1–6.7	31.7	39.3	0.257
30 000–50 000	7.2	5.1–9.9	19.5	22.2
> 50 000	7.2	5.5–9.2	43.9	34.1
Big cities^a	4.6	2.0–9.1	4.9	4.4
Region
Northern	6.5	4.4–9.4	15.0	16.3	0.677
Central	6.6	5.4–7.9	55.0	60.0
Southern	5.5	4.0–7.4	30.0	23.7
SES^b
Non-manual, high	5.1	3.7–6.7	30.3	35.8	0.544
Non-manual, middle	7.5	5.6–9.8	45.5	33.9
Non-manual, low and farmers	7.0	4.0–11.3	6.1	12.8
Manual, high/middle	6.2	3.2–10.9	12.1	7.3
Manual, low	5.7	3.0–9.7	6.1	10.1
Ethnicity
Natives and Western immigrants	6.3	5.3–7.5	97.1	93.0	0.276
Non-Western immigrants	4.3	2.0–8.2	2.9	7.0

n₀: children in the population who reported suffering from warts; n₁: children who suffered from warts and consulted the GP within 14 days before and 3 months after the interview; n₂: children who suffered from warts and who did not consult the GP within this timeframe.

^a Amsterdam, Rotterdam, The Hague.

^b Socioeconomic status; according to father's occupation.

Discussion

Summary of main findings

The self-reported prevalence of warts among Dutch children (0–17 years) is 6.2%; of these children, 23.3% consulted the GP for warts.

Comparison with existing literature

The self-reported prevalence in our study is consistent with one previous study performed among Romanian schoolchildren (6–12 years), showing a prevalence of 6.3% [6]. A Dutch study (1959) among schoolchildren reported a prevalence of 7.2%; the prevalence in our study among children of the same age (5–14 years) is 7.8%, indicating that the prevalence has barely changed over time [7].

In Dutch general practice, the total incidence rate of warts decreased by 28%, from 44.5 (1987) to 32.1 (2001) per 1000 person years, which is proportional to the decreasing overall GP consultation rate [2]. This decrease of the overall GP consultation rate is probably a consequence of an increasing use of over-the-counter medication or other self-care strategies. We do not know what proportion of children suffering from warts primarily used over-the-counter medication or other self-care strategies and did not seek medical help or consulted the GP at a later phase of the disease.

No data about the so-called iceberg phenomenon of warts in the Netherlands are available. However, a previous Dutch study showed that 28% of children (0–17 years) that reported suffering from skin diseases consulted their GP for that reason [8].

Implications for future research or clinical practice

More insight should be gained into what proportion of children with warts primarily apply self-care and do not seek medical help or consult their GP at a later phase of the disease.

Acknowledgements

The authors thank all participating GPs and their staff members for providing data. The Dutch Ministry of Health, Welfare, and Sports mainly funded the surveys directly or indirectly. In addition, the “Stichting Centraal Fonds RVVZ” contributed financially to the second survey. The analysis reported in this paper was made possible through the internal funding of the Department of General Practice, Erasmus MC University Medical Centre Rotterdam. R.S.A.M. and J.C.v.d.W. designed the study. R.S.A.M. carried out the analyses and drafted the paper. All authors commented on draft versions and approved the final manuscript. All authors declare that they have no conflict of interests.

Appendix. Skin diseases and the corresponding International Classification of Primary Care (ICPC) diagnosed by the GPs among helpseekers.

Table

S03	Warts
S05	Lumps/swellings generalized
S06	Rash localized
S11	Skin infection post-traumatic
S20	Corn/callosity
S74	Dermatophytosis
S75	Moniliasis/candidiasis skin
S82	Naevus/mole
S87	Dermatitis/atopic eczema
S88	Dermatitis contact/allergic
S90	Pityriasis rosea
S93	Sebaceous cyst
S95	Molluscum contagiosum