Study design and participants

This cross-sectional study included 1510 participants who took part in the first-year follow-up survey of the Population Health Survey between November 2016—February 2018. This was a longitudinal health survey on the health of a representative sample of community-dwelling adult population living in the central region of Singapore. The details of the study methodology have been described elsewhere [4]. The eligibility criteria were as follows: (1) Singapore citizens or permanent residents aged ≥ 21 years old; (2) stayed in the selected household for ≥6 months; (3) able to answer the survey questions coherently. Written informed consent was obtained and data was collected via surveyor-administered face-to-face interviews. The ethics approval for this study was obtained from the National Healthcare Group Domain Specific Review Board (Reference Number: 2015/00269), Singapore.

Skin diseases

The medical history of skin diseases was obtained by asking the participants a specific question: “Have you ever had any of the following skin conditions [a list of 13 skin conditions]?” This included eczema, acne vulgaris, psoriasis, vitiligo, viral warts, scabies, fungal skin infections, chronic urticaria, bacterial skin infections, chronic ulcers or wounds, skin cancers, alopecia areata, and pruritus; and participants were offered an option of “Others” to specify any other skin diseases not listed. This list was modified from the 15 categories of skin diseases included in the Global Burden of Disease Study 2010 [5]. Clinical photographs of each skin disease were used to assist the interview process.

Instruments and measurements

The outcomes measured in this study were depression, social isolation, loneliness and health-related quality of life (HRQOL).

Statistical analysis

Independent-samples t-tests, Chi-square (χ²) tests or one-way analysis of variance (ANOVA) were used to assess group differences in socio-demographic characteristics, diagnosis of individual skin diseases, number of chronic diseases, and the measured outcomes, specifically depression, social isolation, loneliness, and HRQOL.

Multiple linear regression analysis was used to examine the association of skin diseases with each of the four measured outcomes. In each regression model, the dependent variable was one of the measured outcomes, and the independent variable was history of any listed skin diseases, adjusted for demographics including age group, gender, ethnicity, marital status, highest education level, employment status, self-reported money sufficiency and diagnosis of any chronic conditions. Descriptive statistics were analyzed using Statistical Package for Social Sciences (SPSS) version 18.0 (SPSS, Inc., Chicago, IL) and multiple linear regression was computed using Stata/SE 12 for Windows. The result was considered significant if p-value was <0.05.

Financial strain

This study observed that participants with skin diseases were less likely to be employed and more likely to have financial constraints [Table 1]. Across the study population, participants who were not working (including those unemployed, retired or unfit for work) and reported having insufficient money for daily living needs were more likely to have depressive symptoms [Table 5].

Patients with severe skin conditions are more likely to be unfit for work, while those with mild to moderate disease may be able to work but often require time off to attend consultations or take sick leave during flares. A study in Netherlands showed that 64% of patients with atopic dermatitis took sick leave in a year, as compared to 50% of their healthy counterparts [10]. Frequent time away from work can strain employer-employee relationships and result in termination [11], leading to increased financial strain. It is well-established that people with increased financial burden have higher risk of developing depression [12].

Lack of social relationships

Participants with skin diseases were more likely to be single, including those who were widowed or divorced [Table 1]. Studies have shown that being single increases the risk of developing depression [13]. It is hypothesized that marriage exerts a protective effect on mental well-being, as based on the social support theory of marriage, one’s partner provides not only emotional, but financial and physical support. A study done in United States of America found that adult atopic dermatitis was associated with higher rates of divorce and separation, and postulated that the negative psychosocial impacts of atopic dermatitis such as fatigue, anxiety, depression, sleep disturbances were possible reasons why there was an increased risk of separation and/or divorce [14].

To cope with depression and loneliness, some may turn to maladaptive coping mechanisms such as alcohol. Participants with skin diseases are more likely to have alcohol misuse (28.2%) compared to their healthy counterparts (21%) [Table 1]. This is consistent with a study conducted in the United Kingdom which found that 30.6% of its study subjects with psoriasis had an alcohol misuse disorder compared to 14.3% of the control group [15]. Alcohol misuse not only limits the suitability of various systemic medications used to treat skin conditions, it also further propagates depressive mood symptoms [16].

With a clearer understanding of the psychosocial burden skin diseases have on our patients, we considered a few areas for improvement.

Firstly, more attention should be paid towards patients with a higher risk of developing depressive symptoms, such as those who are not working, single and elderly. Some studies have suggested monitoring patients with a short instrument like PHQ-9 regularly, to detect depression early and refer them to appropriate care accordingly. The early detection of depression is important for patients with any chronic disease, including skin conditions, as studies have shown that patients with depression are three times more likely to be non-adherent to medical treatment as compared to patients without depression [17].

In addition, more emphasis should be placed on psychosocial interventions when managing patients with skin diseases. Existing studies have demonstrated the effectiveness of psychosocial interventions such as cognitive behavioural therapy, both in-person and online [18], mindfulness-based cognitive therapy [19] and structured educational training [20]. These interventions are useful in helping patients positively deal with their condition and promoting adaptation, hence improving patient outcomes [21]. Yet, a local study showed that only 18% of dermatologists report a clear understanding of psychodermatology [22], possibly explaining the scarcity of such interventions in Singapore.

There are several limitations of this study. Firstly, as this was a cross-sectional study, we were unable to clearly ascertain the temporal relationship between skin disease and certain outcomes such as alcoholism. Also, some participants might not have been suffering from skin disease at the point of enrolment, which may have resulted in underestimation of the measured outcomes. Secondly, our study did not evaluate the severity of skin diseases, and hence we were unable to determine the association between severity of skin diseases and measured outcomes. Thirdly, while skin specific quality of life instruments like Dermatology Life Quality Index (DLQI) were not used, EQ-5D has allowed us to compare the impact of skin diseases with other chronic diseases.

Skin diseases have an adverse impact on psychosocial well-being and can lead to more depressive symptoms, social isolation, loneliness and decreased quality of life. The psychological impact of skin diseases is often underestimated compared to that of other chronic diseases. Moving forward, a more holistic approach should be taken to optimise patient care and reduce the burden of skin disease. Some considerations include monitoring patients for mood-related changes regularly and implementing psychosocial interventions early.