Hyperpigmentation disorders: A comprehensive analysis in a worldwide large‐scale study on 50,552 individuals

Dear Editors, Hyperpigmentation disorders (HD) are caused by increased amounts of melanin in the skin.1 UV exposure and hormonal changes alter pigmentation by affecting pigment cell function and proliferation.1 While HD are generally benign, they can be distressing to patients. The WHO has issued a worldwide call for governments to take action2 to reduce stigmatization3 in patients with skin conditions.3The prevalence of HD in the general population has rarely been studied and has mostly been limited to a single center or country.4, 5 Moreover, the impact of hyperpigmentation on daily life and stigmatization has seldom been investigated. Our objective was to conduct the first large-scale worldwide study to assess the prevalence of self-reported HD by sex, age, phototype, and geographic regions, as well as the impact on patients’ daily lives and stigmatization. The “ALL Project” 6-10 included 50,552 individuals, representative of populations ≥ 16 years old in 20 countries that cover half of the world's population: China 5,000; USA 5,000; Brazil 4,001; India 3,000; Australia 2,000; France 4,000; Italy 4,000; Canada 2,500; Denmark 1,000; Germany 2,000; Israel 2,000; Kenya 500; Mexico 2,500; Poland 2,500; Portugal 1,000; Senegal 300; South Africa 1,000; South Korea 2,500; Spain 2,000; UAE 750. Sampling was conducted using the quota method. Selected participants were contacted by personal e-mail to take part in a survey without being informed of the topic. This helped prevent self-selection bias, as individuals with a skin disorder might have been more likely to participate if the purpose of the study had been disclosed. In the online questionnaire, patients were asked to provide their demographic characteristics and phototype based on Fitzpatrick classification. Hyperpigmentation was defined as the presence of one or more dark or brown spots on their skin. Participants were asked whether they had other skin diseases (e.g., psoriasis, atopic dermatitis, vitiligo, acne, or others). Questions on the impact on daily life and stigmatization were addressed only to individuals with hyperpigmentation and no additional skin disease. We did not use a validated questionnaire on stigmatization, i.e., the PUSH-D, which is currently not freely available for clinical research studies. In total, 3,476 of 50,552 individuals reported having an HD, including 2,319 women (66.7%). There were 570 individuals aged 16–24 years, 1,127 aged 25–39 years, 1,393 aged 40–64 years, and 395 aged > 65 years. The worldwide weighted prevalence of HD was 10.6%. It was 6.1% in North America, 9.4% in South America, 4.1% in Europe, 9.5% in the Middle East, 13.7% in Africa, 12.2% in Asia, and 5.8% in Australia. The prevalence by sex, age, phototype, and geographic region is represented in Figure 1. Among those with HD, 1,443 had no other skin conditions. The impact of HD on daily life and stigmatization is shown in Table 1. Our study showed a high worldwide prevalence of HD > 10%. The prevalence was higher in women vs. men in all regions of the world. In fact, most HD like melasma and lentigines are indeed more frequent in women.2, 8 Moreover, dark-skinned individuals had a significantly higher prevalence of HD than fair-skinned individuals: age groups 25–39 and > 65 had a higher prevalence than other age groups. As for geographic regions, the highest prevalence was in Africa and Asia and the lowest in Europe and Australia. HD had an impact on daily life and stigmatization in both, men and women. However, unexpectedly, men were found to be more prone to cancel professional engagements, experience disruptions in their sexual lives, and perceive a sense of rejection from others. Moreover, men were more inclined to perceive others looking at them with disgust, avoiding physical contact, and maintaining distance. The impact on daily life and stigmatization was comparable for individuals with fair and dark skin, although those with dark skin had more tendency to change professional plans. Feelings of stigmatization and impaired daily life were significantly more frequent in individuals younger than 40 years. As a limitation to our study, we did not specify the type of HD. This was done to avoid misleading information by patients. Since the general population is not familiar with medical terms such as melasma and actinic lentigines, we believe that asking whether they have melasma or actinic lentigo is inaccurate. This is why hyperpigmentation was studied as whole entity. The WHO has made a call to reduce stigmatization in patients with all skin conditions.10 However, the skin conditions most frequently studied in this context are atopic dermatitis and psoriasis. HD disorders are often considered benign. We believe our results address this call by providing the first large-scale worldwide data on the impact of a benign skin condition such as HD on stigmatization. Hyperpigmentation is a highly prevalent skin disorder around the world; its impact should not be underestimated, but rather assessed in routine clinical exams, in order to provide a holistic approach for patients suffering from HD. This study was granted by Patient Centricity by Pierre Fabre. M.S.A., C.B., and N.P.C. are employed by Pierre Fabre. C.S., C.T., Y.B.H., B.H., and J.S. declare no conflict of interest in this study.

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