Immune-related skin diseases—including dermatitis, urticaria, alopecia areata, and psoriasis—are prevalent and contribute substantially to the GBD (1, 2) and represent a diverse group of disorders characterized by aberrant immune responses targeting the skin (3–5). Though not always life-threatening, these disorders can result in persistent physical symptoms and psychological distress, even after clinical remission (6). Their long-term impact affects quality of life and imposes a notable burden on caregivers, health systems, and society at large. The prevalence and distribution of dermatological conditions have been explored in various geographic contexts. These studies underscore the importance of recognizing immune-related skin disease as part of a broader autoimmune and inflammatory spectrum. With the rise in the SDI, multiple studies have shown that environmental and lifestyle transitions—such as gut microbiota dysbiosis, excessive hygiene leading to reduced microbial exposure (the “hygiene hypothesis”), urbanization, and dietary changes—may contribute to the increasing incidence of immune-related skin diseases (7–9). These disorders share several common influencing indicators, including genetic susceptibility, immune dysregulation, psychosocial stress, and environmental pollutants, all of which can disrupt immune homeostasis and damage the skin barrier. Therefore, understanding the shared epidemiological patterns and trends of these diseases is essential to developing integrated prevention and public health strategies.

During the COVID-19 pandemic in Turkey, notable shifts in dermatologic disease patterns were observed, potentially reflecting the impact of altered environmental or societal factors on disease epidemiology (10). Alopecia areata is primarily characterized as an autoimmune disorder involving T-cell-mediated attack on hair follicles, leading to non-scarring hair loss (11, 12). A focus on alopecia areata’s epidemiology is provided by Augustin (13), who was analyzed longitudinal claims data in Germany. Their findings highlight the population-wide prevalence and associated comorbidities, emphasizing the autoimmune nature of alopecia areata and its frequent coexistence with other systemic conditions. Alopecia areata is part of a broader autoimmune and inflammatory spectrum. A systematic review has examined the inflammatory and autoimmune aspects of urticaria, including the potential anti-inflammatory effects of antidepressants and possible associations with mood disorders (14).

This connection supports the biopsychosocial model of dermatologic disease epidemiology, which emphasizes the interplay of biological, psychological, and social factors in disease development (15). Psoriasis, a chronic inflammatory skin disease, is also associated with systemic comorbidities. Psoriasis, along with other skin diseases, involves autoimmune and inflammatory mechanisms, highlighting the need for targeted therapies and biomarker development to address unmet medical needs (16).

Overall, the literature underscores that immune dermatologic conditions such as dermatitis, urticaria, alopecia areata, and psoriasis are prevalent across populations and frequently coexist with both physical and mental health disorders (17). Accurate epidemiological data on immune-related skin diseases are essential for guiding health policy, allocating resources, and designing prevention strategies. Yet, most previous research has focused narrowly on specific conditions or regions, leaving a gap in comprehensive, cross-national comparisons (18, 19). To address this, updated global data on the geographic and temporal trends of these diseases are urgently needed. Such insights are critical to improving disease monitoring, optimizing interventions, and reducing unnecessary healthcare costs.

This study draws on prevalence, DALYs, and incidence for immune-related diseases, disaggregated by location, sex, and age (20). Using the latest data from the GBD study, we conducted a comprehensive analysis of immune-related skin diseases across 204 countries from 1991 to 2021, aiming to provide evidence-based guidance for public health policy development in this field.

Annual case counts and ASR of incidence, prevalence, and DALYs for immune-related skin diseases, including dermatitis, urticaria, alopecia areata, and psoriasis, were obtained for the period 1991–2021. According to the Global Burden of Disease (GBD) database classification, the term “dermatitis” in this study includes the following categories: atopic dermatitis (ICD-10: L20), contact dermatitis (L23), and seborrheic dermatitis (L21). In addition, urticaria corresponds to ICD-10 code L50, alopecia areata to L63, and psoriasis to L40. Prevalence was selected as the primary measure for analysis because it most accurately reflects the patient burden, provides stable estimates over time, and allows for reliable cross-regional comparisons. All data were sourced from the GBD study, coordinated by the Institute for Health Metrics and Evaluation. The GBD offers comprehensive, standardized estimates of disease, injury, and risk factor burdens across countries and time periods, and serves as a critical resource for global health policy and planning (21).

This study included data from 204 countries and territories, categorized into five SDI levels—ranging from low to high—and geographically grouped into 21 regions, including high-income Asia Pacific and Central Asia (22). SDI, scaled from 0 to 1, integrates per capita income, education, and fertility. Based on GBD 2021, 204 countries were stratified into five SDI levels. This allows comparison of immune-related skin disease burden across socioeconomic levels and assessment of its association with global development disparities.

We extracted annual data on prevalence, incidence, and DALYs across global, regional, and national levels. Prevalence and mortality were expressed per 100,000 population (23). SDI, ranging from 0 to 1, was derived from total fertility rate, income per capita, and mean years of education among those aged 15 and above, with higher values indicating greater development (24). This analysis adhered to the Guidelines for Accurate and Transparent Health Estimates Reporting for cross-sectional studies (25). Given the low fatality of immune-related skin diseases, GBD does not report its mortality estimates; instead, the age-standardized prevalence rate (ASPR) serves as the primary metric for burden assessment, as these conditions contribute little to years of life lost (YLLs). To capture both new cases and non-fatal health loss, we also calculated age-standardized incidence (ASIR) and DALY rates, with the latter integrating fatal and non-fatal losses to summarize total population health gaps.

All results are presented per 100,000 population, accompanied by 95% uncertainty intervals (UIs). These intervals were derived from the 2.5th and 97.5th percentiles of 1,000 draws from the posterior distribution generated by the Bayesian meta-regression model (DisMod-MR 2.1). In the Global Burden of Disease Study 2019 (GBD 2019), 95% uncertainty intervals (UIs) were calculated for each metric to represent the uncertainty surrounding the estimates. These UIs were defined by the 2.5th and 97.5th percentiles of 1,000 ranked values (20).

To analyze temporal trends in immune-related skin diseases, Time series forecasting was performed using the Holt’s damped trend exponential smoothing (ETS(A,Ad,N)) model, which extends the classical Holt linear trend model by incorporating a damping parameter to prevent the trend from extrapolating indefinitely. This model assumes additive errors, additive damped trend components, and no seasonality. Model parameters, including the smoothing coefficients ( α, β*) and the damping factor ( Φ), were estimated by minimizing the sum of squared errors through maximum likelihood estimation. Model selection was based on the Akaike information criterion (AIC) and Bayesian information criterion (BIC), while predictive performance was evaluated using mean absolute percentage error (MAPE) and root mean square error (RMSE) (26, 27). This approach has been widely adopted for short- to medium-term forecasting due to its stability and interpretability to predict future trends from 2022-2035.

We analyzed ASR of incidence, prevalence, and DALYs using Joinpoint regression to calculate EAPC and assess temporal trends (1991–2021) (28). Sensitivity analyses were conducted to assess the robustness of temporal trend estimates derived from Joinpoint regression. Models with 3 joinpoints were compared using the Bayesian Information Criterion (BIC) and permutation tests (p< 0.05). All analyses were performed using R software, version 4.2.2, with two-sided p< 0.05 indicating a statistically significant difference.

Based on the systematic analysis done by the GBD 2021, this study provides up-to-date insights into the global, regional, and national burden of immune-related skin diseases from 1990 to 2021, and forecasted estimates of disease burden to 2035 for the first time. The analysis showed that different diseases and regions showed significant gender, age, and socioeconomic-related differences. Disease burdens in low-SDI regions may be underestimated due to underdiagnosis and limited surveillance (29), While the higher burden of skin immune diseases in high-SDI regions may partly reflect greater diagnostic capacity.

Alopecia areata is the most prevalent autoimmune disorder and the second most prevalent hair loss disorder after androgenetic alopecia. Alopecia areata showed a female-male ratio of 1.87:1, which is further supported by ten hospital-based studies worldwide reporting a female predominance with ratios ranging from 2.6:1 to 1.2:1 (30–35). This cause may be related to gender-related immune mechanisms, where the immune system erroneously targets hair follicles, leading to patchy hair loss. The incidence of alopecia areata based on self-reported data is relatively low, which may lead to an underestimation of its true global burden (36). Emerging evidence suggests that the pathogenesis of immune-related skin diseases may be linked to dysbiosis of the microbiota (37). Certain ethnic groups have a higher prevalence of alopecia areata in women; for example, Hispanic, Asian/Pacific Islander, and African American women have significantly higher age-and sex-adjusted prevalence rates than non-Hispanic white women (38). Our data indicate that Spain’s ASPR of 57.71 (95% UI: 55.94–59.70) exceeds the global average of 42.87, a finding that aligns with our overall research observations. The pathogenesis of alopecia areata in women may involve both immune attacks on hair follicles triggered by hormonal fluctuations (e.g., estrogen, progesterone) (39) and molecular pathways associated with dysregulated activity of localized aromatase and 5α-reductase (40). Women are more likely to suffer from psychological disorders (such as anxiety and depression) due to hair loss (41). Numerous studies have underscored the psychological health challenges frequently observed in patients with alopecia areata (42, 43). The increased prevalence of alopecia areata in women may be attributable to gender-related immune mechanisms (44, 45), ethnic and age-related predispositions (46), and potentially external physical factors. These observations highlight the multifactorial etiology of the disease, and further investigation is warranted to elucidate these potential associations. Notably, the prevalence of dermatitis, psoriasis, and alopecia areata all increased with higher SDI levels. These disparities may be partly attributed to differences in socioeconomic development, environmental exposures, and healthcare accessibility.

Psoriasis is a systemic inflammatory condition with effects extending beyond the skin. Our findings reveal notable geographical variations in both the prevalence and disease burden of psoriasis (47, 48). Psoriasis accounted for a disproportionately high proportion of total DALYs – approximately 9–12% – compared to its contribution to the overall incidence rate (<1%). The significant long-term disability associated with psoriasis likely stems from its chronic nature, comorbidities, and substantial reduction in quality of life. Its chronic inflammatory state can lead to joint involvement, causing structural damage and functional limitation, and can affect other organ systems (49). Psoriasis is frequently associated with comorbidities such as obesity, diabetes, and hypertension, collectively accelerating cardiovascular disease progression (50). Notably, the risk of major adverse cardiovascular events, including myocardial infarction and peripheral vascular disease, correlates positively with psoriasis severity, as measured by psoriasis area and severity index scores (51). The disability associated with psoriasis arises from the complex interplay of biological, psychological, and social factors, necessitating multidisciplinary management to improve long-term outcomes (52). Our study further reveals a significant increase in the global prevalence of psoriasis between 2019 and 2021, a resurgence possibly influenced by the COVID-19 pandemic (53). The COVID-19 pandemic highlighted the difficulties in managing immunosuppression or immunomodulation, treatment modification, and the initiation of new therapies in patients with conditions such as psoriasis, atopic dermatitis, and hidradenitis suppurativa (54). Emerging evidence suggests SARS-CoV-2 infection may exacerbate psoriasis, supported by elevated plasma inflammatory cytokines (e.g., granulocyte-colony stimulating factor, tumor necrosis factor-alpha) correlating with disease severity (55, 56). These findings underscore the importance of early identification and comprehensive management of psoriasis, not only as a dermatologic disorder but as a systemic disease with substantial global health implications.

Urticaria, commonly known as hives, is a prevalent dermatological condition characterized by transient, pruritic wheals that can significantly impair quality of life. Our research suggested urticaria exhibits a peak prevalence in early childhood. Children under five years, particularly girls, show the most rapid increase in urticaria prevalence and a significantly rising absolute disease burden. The disease burden, as measured by the DALY rate, is higher in female children than in males (57). Acute urticaria is far more common than chronic urticaria in the pediatric population, with approximately 20% of children experiencing acute episodes (58). While urticaria in children under ten is primarily acute and often self-limiting, vigilance regarding long-term management and quality of life remains essential for the minority of cases progressing to chronicity. Despite this stability, the disease’s impact varies among different regions and populations. Similarly, in South Africa, a review of data from two tertiary referral centers in Cape Town provided insights into the local epidemiology of urticaria (59). Their study emphasizes that while the overall prevalence may be similar to global estimates, regional factors influence disease presentation and healthcare utilization. The epidemiology of urticaria in children has been examined through an analysis of data from insured German individuals under 18 years of age (60). Their retrospective study demonstrated that pediatric urticaria is a significant health issue, with patterns in incidence and diagnosis. Furthermore, the epidemiology of urticaria in older adults has been explored by Patruno, highlighting unique clinical considerations and management challenges in this age group (61). Emerging research also points to increasing recognition of urticaria in specific populations, such as pregnant women and the elderly. Epidemiological considerations in pediatric, pregnant, and lactating populations have been highlighted in recent research (62). These insights are essential for developing age-appropriate management strategies.

In our research, atopic dermatitis, contact dermatitis, and seborrheic dermatitis all showed consistently higher prevalence and incidence rates in females than in males across all SDI regions. Multiple studies have reported that the prevalence of atopic dermatitis in adult females is significantly higher than in males (63, 64). Potential food allergens present in cosmetic products may serve as triggers for atopic dermatitis development (65). Although contact dermatitis had the highest incidence worldwide, atopic dermatitis contributed the most to the global disease burden, indicating that its impact on disability and quality of life is disproportionately greater relative to its incidence. Although the global incidence of atopic dermatitis is lower than that of contact dermatitis, its chronic, relapsing nature, and systemic effects—such as Th2 immune dysregulation and associated comorbidities—contribute to a more substantial long-term cumulative burden (66). This is further evidenced by the fact that the growth rate of AD-related DALYs outpaces its incidence growth, highlighting its disproportionate disease burden (67). Moreover, the economic impact of atopic dermatitis encompasses both direct treatment costs and indirect productivity losses, with a particularly pronounced burden in middle-income countries (68).

Early investigations that emphasized the widespread nature and rising prevalence of atopic dermatitis have been substantiated by our studies (69). Subsequent studies have emphasized the rising incidence of atopic dermatitis while also exploring its potential causes, suggesting that both environmental and genetic factors play crucial roles in disease development (70). Recent data showed a rising prevalence of atopic dermatitis, affecting 10–20% of U.S. children, with about 10.7% newly diagnosed each year (71).

Females are the predominant group among patients with facial contact dermatitis (71.06% vs. 28.94%) and exhibit a higher rate of positive patch test reactions (72). This sex disparity is closely linked to behavioral exposure patterns; adolescent females (aged 12–18) have significantly greater exposure to cosmetics and metal accessories (e.g., earrings), resulting in a 2.9-fold increased risk of cosmetic-related contact dermatitis compared to males (OR = 2.9) (73). Moreover, during the COVID-19 pandemic, females were more susceptible to facial dermatitis triggered by prolonged mask wear, attributed to friction and a localized humid environment, with common clinical manifestations including bilateral cheek itching and erythema (74). Meanwhile, the high prevalence but relatively low incidence of contact dermatitis suggests that the condition tends to be chronic or recurrent, with a prolonged disease duration and incomplete recovery in many patients. This pattern implies that once contact dermatitis develops, it often persists or relapses, highlighting the need for long-term prevention and management strategies. Occupational exposure—such as to medical equipment and hairdressing chemicals—or contact with essential daily items like nickel-containing products makes complete allergen avoidance unrealistic, leading to recurrent episodes of the disease (75). Data from the Finnish national registry indicate that contact dermatitis can result in prolonged sick leave and loss of work capacity, underscoring the chronic course and substantial socioeconomic burden of the condition (76).

During the COVID-19 pandemic, a study reported that among 228 patients, at least one hair disorder was identified, with seborrheic dermatitis being the third most common condition, following telogen effluvium and hair graying (77). Further research is warranted to elucidate the relationship between seborrheic dermatitis and COVID-19. Another study demonstrated that the detection rate of seborrheic dermatitis was significantly higher in females than in males (p = 0.015), and that female patients tended to develop the disease at an earlier age (p = 0.048) (78). Our research further supports this conclusion.

This study has several limitations. First, the dataset lacked detail on disease subtypes and severity, preventing analyses of acute versus chronic forms. Second, underdiagnosed, self-limiting, or mild cases may be underestimated, particularly in regions with limited healthcare access. Third, sparse or inconsistent data from underrepresented regions could affect estimate reliability. Fourth, improvements in diagnostics and reporting over time may confound temporal trends. Fifth, aggregated data precluded assessment of individual-level factors, limiting causal inferences. Additionally, the GBD database does not capture natural remission, potentially overestimating prevalence. Additionally, the GBD database does not capture natural remission, potentially overestimating prevalence. In addition, the projections presented in this study are based on the Holt’s damped trend exponential smoothing model (ETS(A,Ad,N)), which relies on historical trends of incidence and prevalence. These forecasts assume a continuation of current patterns and do not explicitly account for potential changes in healthcare access, novel interventions, policy shifts, or unexpected events (e.g., pandemics). Therefore, while the model provides reasonable short- to medium-term estimates, the predictions should be interpreted as trend-based scenarios rather than precise forecasts. Uncertainty intervals are provided to reflect potential variability, but caution is advised when extrapolating beyond the observed data range.