FormalPara Key Summary Points

Atopic dermatitis leads to significant morbidity and quality of life impairment, often affecting certain populations disproportionately.

Displaced populations, most often including patients with skin of color, are particularly vulnerable to the detrimental effects of atopic dermatitis.

Poor living conditions, climate change events, psychological stress, and lack of access to medical care contribute to an increased disease burden of atopic dermatitis in displaced populations.

Introduction

Atopic dermatitis (AD) is a chronic inflammatory skin disease characterized by relapsing eczematous lesions and pruritus often leading to significant morbidity and quality of life impairment. Recent advancements in our understanding of AD have shown that certain populations carry larger disease burdens than others, particularly patients with skin of color (SOC) [1]. For instance, Black, Latino, and Asian patients are much more likely to visit their physician for AD than white patients in the USA [2]. African American children are 1.7 times more likely to develop AD than European American children after controlling for possible confounders [3]. Additionally, Black children with AD have a six times greater risk of having severe AD than their white counterparts [4]. In the USA, the origin of these disparities is likely multifactorial, often reflecting elements of structural, environmental, and interpersonal racism [5].

From a global perspective, little has been published on the burden of atopic dermatitis and other inflammatory skin diseases experienced by the large number of refugees, migrants, and asylum seekers around the world. Owing to its unique risk factors, this SOC subpopulation is particularly vulnerable and, therefore, requires special consideration by dermatologists as well as the global medical community at large. In this review, we outline the different factors contributing to AD susceptibility or aggravation in displaced populations, particularly refugees, migrants, and asylum seekers. This article is based on previously conducted studies and does not contain any new studies with human participants or animals performed by any of the authors.

Terminology of Displaced Persons

There are many terms to describe displaced individuals. This includes refugee, migrant, asylum seeker, and internally displaced person (IDP). Although these groups may share common risk factors and social determinants of health, they are not synonymous. The formal definitions of these terms are summarized in Table 1. Data from the year 2021 show that the most refugees come from nations with majority SOC populations. In fact, more than two-thirds of the 25.7 million refugees and Venezuelans displaced abroad originated from just five countries: Syria (6.8 million refugees), Venezuela (4.4 million displaced abroad), Afghanistan (2.7 million refugees), South Sudan (2.3 million refugees), and Myanmar (1.1 million refugees). Similar trends are seen with asylum seekers [6, 7].

Table 1 Key terms describing displaced individuals
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Prevalence of Atopic Dermatitis in Displaced Groups

Although skin disease is reportedly ubiquitous among displaced populations, studies show that the prevalence of AD varies depending on a number of factors [13, 14].

For example, Saikal et al. investigated the profile of skin disease among refugees living in Al Za’atari refugee camp or presenting to community clinics in Jordan. They reported that “inflammatory conditions of the skin and subcutaneous tissue” was the most common diagnostic category, with “atopic dermatitis and eczemas” being the most common clinical entity, presenting in one-third of all patients assessed [15].

Additionally, Wollina et al. collected data from asylum seekers in a German refugee camp and found “eczematous dermatitis” to be the second leading diagnosis, with scabies being the most common diagnosis among the studied group [16]. Furthermore, Di Meco and colleagues led a cross-sectional study in collaboration with the Italian National Institute for Health Migration and Poverty (INMP). They reported that “dermatitis” was present in 7.5% of the 6188 migrants evaluated, making it the fifth most frequently encountered condition [17]. Finally, a study of 1182 patients from orphanages and refugee camps in rural Sudan found that “dermatitis/eczema” was present in less than 4% of patients [18].

It remains difficult to accurately estimate the prevalence of AD in displaced groups as there is a paucity of studies on the epidemiology of dermatologic disease in displaced communities. Additionally, many of the extant studies including the aforementioned articles often group atopic dermatitis with other eczematous disorders and report their prevalence under umbrella terms such as “eczematous dermatitis,” “dermatitis,” “contact dermatitis and other eczema,” or other categories [16, 17, 19]. The variety of terms are summarized in Table 2. Studies in nondisplaced populations have shown significant variation in AD prevalence across ethnicities; For example, in the USA, studies have found that African American children are 1.7 times more likely to develop AD than European American children, even after adjusting for confounders [20].

Table 2 Select publications related to the prevalence of AD in displaced communities
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In addition to limitations in resources such as time, funding, and workforce, there are a host of methodological obstacles that make it difficult to design studies to estimate AD prevalence in displaced populations. These include differences in the diagnostic criteria used for AD, sample design, and populations covered.

Refugee camps are typically formed by ethnically diverse groups of individuals. Since AD prevalence can vary by ethnicity and country of origin, the prevalence of AD in a randomly selected sample of refugees may not be representative of the true AD prevalence in the entire population of refugees. The morphology or phenotype of AD in individuals with SOC is another complicating factor. For example, the masking of erythema in SOC may especially contribute to missed diagnoses and subsequently affect the estimated prevalence. Lack of trust in foreign health institutions or mistrust of local health providers can lead to lack of participation in prevalence studies by select refugee groups more than others, further compromising prevalence estimates. Finally, comparing AD prevalence in refugee populations with the general population while controlling for relevant variables remains a challenge as data on AD prevalence in many global regions remain scarce.

Whether the prevalence of AD is higher or lower in displaced communities than the general population remains to be elucidated. Regardless of the true prevalence, there are a host of unique aggravating and complicating factors affecting those with preexisting AD in displaced communities. These factors are often related to poor living conditions, climate change events, psychological stress, and lack of access to medical care.

Poor Living Conditions

The substandard living conditions of refugees and migrants have been well documented. Low-quality housing is particularly common in refugee camps and immigrant resettlement communities [21,22,23,24]. Studies on these dwellings have identified many aspects that pose health risks. This includes excess dampness/humidity, mold growth, poor ventilation, pest infestation, overcrowding, and nonfunctioning sanitation facilities [21,22,23,24]. Refugees or migrants with AD living under these conditions can suffer from exacerbations or complications through various mechanisms. For example, exposure to dust mites—a known aggravator of AD—is common among refugees, as many refugee camps have been shown to suffer from dust mite infestations [25,26,27]. Similarly, sweating can induce pruritus and exacerbations of AD [25]. Interestingly, studies have shown that showering after episodes of sweating can help relieve symptoms of AD [28, 29]. Refugees and migrants often suffer from suboptimal hygiene due to the nature of their built environment and the lack of access to washing facilities. Sweating in this population might also be increased due to humidity and poor ventilation, further compounding the likelihood of AD exacerbation.

Additionally, overcrowding can foster the spread of skin infections and infestations [30]. This effect is likely augmented due to the increased risk for cutaneous infections from barrier defects and suppression of innate cutaneous immunity in patients with AD [31]. Studies have shown that poverty and overcrowding are independent risk factors for both impetigo and scabies [32,33,34]. Scabies infestations are prominent in refugee camps and among migrant populations [16, 35, 36]. The intense pruritus associated with scabies often leads to heavy morbidity, and the resultant excoriations predispose to secondary skin infections such as impetigo and cellulitis [32]. Refugees and migrants with AD are therefore rendered especially vulnerable to bacterial skin infections that may exacerbate their disease.

In addition to low-quality housing, the act of migration itself often subjects individuals to harmful exposures. For example, migrants traveling by sea may suffer from skin irritation due to prolonged immersion in seawater and contact with boat material such as kerosene, petrol, vapors, fumes, and dust [37,38,39]. In some instances, this can lead to severe cases of irritant contact dermatitis, a known trigger of AD [25, 37]. Migrants and refugees who undergo water submersion during flooding events often suffer from inflammatory and infectious skin disease as well [40].

Overall, the adverse living conditions associated with migration and refugee camps confer an increased risk of various diseases, commonly skin infections and infestations, whose downstream effects frequently lead to aggravation or complication of AD in affected patients.

Climate Change

Anthropogenic climate change is poised to have a significant impact on dermatologic disease, in particular AD. Climate change affects AD in numerous ways, both directly and indirectly; a summary of the effects of climate change on AD is presented in Table 3. Per the United Nations High Commissioner for Refugees (UNHCR), displaced people are at the “frontlines of the climate emergency” [41]. Furthermore, the UNHCR concludes that displaced populations are often at the “hotspots” of climate change-induced events and are the least equipped to adapt to the catastrophic effects of climate change [41].

Table 3 Factors related to climate change and their effect on atopic dermatitis
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Air pollution, which both contributes to climate change and is worsened by climate change, can significantly affect patients with atopic dermatitis. For instance, air pollutants such as nitrogen oxides, particulate matter, formaldehyde, and sulfuric particles have been shown to worsen symptoms of AD [42,43,44,45]. Polycyclic aromatic hydrocarbons (PAHs), pollutants produced from vehicle emissions, forest fires, volcanoes, and industrial processes, can coat particulate matter and penetrate the skin due to their lipophilic nature [46]. PAHs have been linked to provocation of allergic responses and have even been shown to aggravate AD-like skin lesions in mice [46,47,48]. Additionally, a recent study focused on wildfire-related air pollution found an association between increased particulate matter and healthcare use for AD and itch [49]. When considering displaced people, it is imperative to remember that 60–80% of displaced populations live in urban areas, where air pollution affects those most [50, 51]. In addition to air pollution, higher temperatures due to climate change can lead to an earlier and higher intensity of pollen, potentially exacerbating AD in select patients [52, 53].

Anthropogenic climate change has also been shown to be associated with more frequent and intense extreme weather events, including heat waves, floods, droughts, and wildfires [54]. These environmental catastrophes will not only lead to the displacement of whole communities, creating new groups of refugees and migrants, but also disproportionately affect groups who are already displaced. As displaced people most often have limited resources and infrastructure, they will be the least prepared to deal with extreme weather events, and their living conditions and well-being will suffer further. Additionally, as the number of displaced people grows, the communities in which they live may become overcrowded, worsening the scarcity of resources in these communities and contributing to poorer health outcomes. Thus, climate change, and extreme weather events in particular, have the potential to create displaced groups of people and in turn significantly worsen health outcomes of already displaced people.

Patients with AD will be affected by extreme weather events in unique ways. For instance, there is considerable psychological stress that results from experiencing an extreme weather event [55]. This stress can contribute to exacerbation of atopic dermatitis, as discussed further in the “Psychological Stress” section. Furthermore, a recent study from Taiwan found evidence suggesting a pathophysiologic link between flooding and AD severity. This study, which controlled for air quality and temperature, found that visits to the emergency department for AD were increased during weeks in which Taiwan Island experienced floods [56]. The increased risk for cutaneous infections in AD mentioned above may be even further exacerbated by extreme weather events [31]. This can occur through greater exposure to microbes in contaminated flood water or destruction of the resources necessary to prevent transmission of infectious disease [57]. For example, fungal infections can thrive in the abundant wet surfaces following floods and tsunamis. A study following the 2004 Indian Ocean tsunami found that the most common skin disorder in the aftermath was tinea corporis [58]. The secondary effects of extreme weather events such as population overcrowding and increased stagnant water, which can serve as breeding grounds for vector-borne diseases, may also further increase the risk of cutaneous infections in migrant populations with AD [59].

Psychological Stress

The process of displacement is typically marked by various traumatic experiences. Persecution in all its forms and exposure to violence, war, and natural disasters are all examples of stressors that a refugee, migrant, or asylum seeker may experience prior to or during displacement. These experiences can have long-lasting effects on psychological well-being [62]. In fact, research shows that displaced persons have a higher prevalence of psychological disorders than the general population [62,63,64]. Depression, anxiety, and posttraumatic stress disorder (PTSD) in particular are present at high rates, often co-occurring in some individuals in this vulnerable population [62, 65,66,67,68,69]. In addition to premigration trauma, displaced persons frequently encounter postmigration stressors. These stressors may be due to socioeconomic factors such as financial and housing insecurity or interpersonal factors such as family separation and social isolation [70]. For displaced persons with AD, these stressors may exacerbate their condition. Emotional stress has been shown to increase itching and release of inflammatory mediators in patients with AD [71, 72]. Furthermore, repeated scratching behavior due to emotional stress may lead to a vicious cycle of scratching out of habit and in the absence of itching (habitual scratching), causing further skin damage and disease morbidity [25]. Although stress management and behavioral modifications have been shown to improve itching symptom of AD, displaced communities often have limited access to healthcare services, including mental health services, compounding their disease and perpetuating health disparities [73].

Access to Care and Health-Related Behaviors

Access to healthcare is a significant issue within displaced populations. Difficulty navigating foreign healthcare systems, limited financial and transportation-related resources, and communication barriers are ways in which displaced people receive decreased quality of care [74, 75]. Dermatologic care may be even more difficult to access for this population. Consider traditional healthcare service models, which most often provide dermatologic care through referral systems. To an ordinary citizen, this may not be an obstacle to healthcare; however, to a displaced person, there are many inequities in this process. Firstly, the use of secondary healthcare services may often rely on co-payments or out-of-pocket payments for migrants, presenting a financial obstacle to a group usually without significant financial resources [76]. Additionally, studies have found that referral services are often not well understood by new migrants [76]. The countries in which displaced people make their home also vary and evolve in their laws regarding healthcare of refugees, migrants, and asylum seekers [77, 78]. Notably, this has become a controversial and heavily politicized issue in many of these countries. For instance, Spain restricted access to healthcare for undocumented migrants in 2012, resulting in poorer health outcomes [79]. These inequities are likely worsened in the case of AD, a chronic, relapsing disease that requires consistent follow-up. Migrants and refugees may often not be able to establish a long-term therapeutic relationship with a provider while on their journey to a new country or area [76]. Furthermore, there may not be any standardized medical record system to document their treatment, limiting the opportunity to make proper therapeutic decisions in the future.

Conclusions

Skin disease remains a major issue affecting displaced populations such as refugees, migrants, and asylum seekers. Chronic inflammatory conditions, such as AD in particular, carry a heavier toll on patients in this group compared with the general population. This disparity is due to a multitude of factors, including but not limited to poor living conditions, climate change, psychological stress, and limited access to medical care and health-related behaviors. We hope that this unique review underscores the unmet health needs of this vulnerable patient population and encourages interventions from interested parties including clinicians, researchers, policymakers, and other stakeholders to address these health disparities. Finally, there is a need for additional research on skin disease in displaced communities and potential long-term strategies to address their needs in the future.