European Journal of Cardiovascular Medicine

Rosacea is a chronic inflammatory skin condition characterized by facial erythema, telangiectasia, papules, and pustules[1]. It affects approximately 5.46% of the global population, with a higher prevalence among individuals with lighter skin phototypes[2]. Rosacea can significantly impact the quality of life of affected individuals, causing emotional distress, social stigma, and decreased self-esteem[3].

The pathogenesis of rosacea is complex and multifactorial, involving genetic, environmental, and immunological factors[4]. While the exact cause of rosacea remains unclear, various environmental factors have been implicated in the exacerbation and severity of the condition[5]. These factors include exposure to ultraviolet (UV) radiation, temperature extremes, wind, humidity, and air pollution[6].

UV radiation, particularly UVA and UVB, has been shown to trigger and aggravate rosacea symptoms[7]. UV exposure can lead to the production of reactive oxygen species (ROS), which cause oxidative stress and inflammation in the skin[8]. Additionally, UV radiation can stimulate the production of matrix metalloproteinases (MMPs), enzymes that degrade collagen and contribute to the development of telangiectasia and skin aging[9].

Temperature extremes, both hot and cold, can also exacerbate rosacea symptoms. Heat exposure can cause vasodilation and increased blood flow to the skin, leading to facial flushing and erythema[5]. Conversely, cold temperatures and wind can cause vasoconstriction and irritation, triggering the release of inflammatory mediators and worsening rosacea symptoms[6].

Humidity and air pollution have also been associated with the severity of rosacea. High humidity levels can increase the growth of Demodex mites, which have been implicated in the pathogenesis of rosacea[10]. Air pollution, particularly particulate matter, and nitrogen oxides, can cause oxidative stress and inflammation in the skin, contributing to the exacerbation of rosacea symptoms[6].

Despite the recognized impact of environmental factors on rosacea, there is a lack of comprehensive observational studies investigating the relationship between these factors and the severity of the condition. This study aims to address this gap by conducting a large-scale observational study to assess the impact of various environmental factors, including UV radiation, temperature, humidity, and air pollution, on the severity of rosacea symptoms. The findings of this study will provide valuable insights into the role of environmental factors in the management and prevention of rosacea, ultimately improving the quality of life for affected individuals.

AIMS AND OBJECTIVES

The primary aim of this observational study was to investigate the impact of environmental factors, including ultraviolet (UV) radiation, temperature, humidity, and air pollution, on the severity of rosacea symptoms for one year. The secondary objectives were to identify potential correlations between specific environmental factors and the exacerbation of rosacea symptoms, as well as to assess the influence of these factors on the quality of life of affected individuals.

Study Design and Participants

This prospective observational study was conductedover a sample size of 100 participants, over a period of one year.

The inclusion criteria were as follows: (1) adults aged 18 years or older, (2) a confirmed diagnosis of rosacea by a dermatologist, and (3) willingness to participate in the study and provide informed consent.

Exclusion criteria included: (1) the presence of other inflammatory skin conditions that could confound the assessment of rosacea severity, (2) the use of systemic or topical medications that could influence rosacea symptoms, and (3) the inability to comply with the study protocol.

Data Collection

At the initial visit, participants underwent a comprehensive dermatological examination, and their rosacea severity was assessed using the National Rosacea Society Expert Committee (NRSEC) grading system. Participants also completed a quality-of-life questionnaire (Dermatology Life Quality Index, DLQI) to evaluate the impact of rosacea on their daily activities and emotional well-being.

Throughout the study period, participants were asked to keep a daily diary recording their exposure to environmental factors, including UV radiation (measured using a personal UV dosimeter), temperature, humidity, and air pollution (assessed using data from local environmental monitoring stations). Participants also documented any changes in their rosacea symptoms, such as increased erythema, flushing, papules, or pustules.

Follow-up visits were conducted every three months, for one year, during which rosacea severity and quality of life were reassessed. Participants' daily diaries were reviewed, and any adverse events or changes in medication use were recorded.

Data Analysis

Descriptive statistics were used to summarize participant characteristics, rosacea severity scores, and quality of life scores at baseline and each follow-up visit. Regression analyses were performed to investigate the relationships between environmental factors and changes in rosacea severity over time. Correlation coefficients were calculated to identify potential associations between specific environmental factors and rosacea symptoms. Subgroup analyses were conducted based on age, gender, and rosacea subtype to identify any potential differences in the impact of environmental factors on rosacea severity.

Ethical Considerations

The study protocol was approved by the Institutional Review Board (IRB) of the participating institutions. All participants provided written informed consent prior to enrolment in the study. Participants' personal information was kept confidential, and data were anonymized for analysis and reporting purposes.

We ensured that the study subjects have a choice for voluntary participation and patient confidentiality and human subject protection was ensured. Ethical guidelines of the declaration of Helsinki of 1975, as revised in 2000 were followed in all aspects of the study.

Baseline Characteristics

The study included 100 participants with a mean age of 45.6 years (SD 12.3). Most of the participants were female (68%), and the distribution of rosacea subtypes was 55% erythemato-telangiectatic and 45% papulopustular. The mean rosacea severity score at baseline was 3.2 (SD 1.1), and the mean quality of life score was 12.4 (SD 4.7) (Table 1).

Environmental Exposure

Throughout the study period, participants were exposed to a mean UV radiation of 15.3 Joules/cm² (SD 6.2), a mean temperature of 18.7°C (SD 5.4), a mean humidity of 62.5% (SD 10.1), and a mean air pollution level of 28.4 μg/m³ (SD 8.6) (Table 2).

Rosacea Severity

Rosacea severity scores decreased significantly from baseline to each follow-up visit (Table 3). At 3 months, the mean rosacea severity score was 2.9 (SD 1.0), representing a change of -0.3 from baseline (p=0.02). At 6 months, the mean score was 2.7 (SD 0.9), with a change of -0.5 from baseline (p=0.001). At 9 months, the mean score was 2.5 (SD 0.8), with a change of -0.7 from baseline (p<0.001). At 12 months, the mean score was 2.4 (SD 0.8), representing a change of -0.8 from baseline (p<0.001).

Quality of Life

Quality of life scores also improved significantly from baseline to each follow-up visit (Table 4). At 3 months, the mean quality of life score was 11.2 (SD 4.2), with a change of -1.2 from baseline (p=0.03). At 6 months, the mean score was 10.1 (SD 3.9), representing a change of -2.3 from baseline (p=0.001). At 9 months, the mean score was 9.3 (SD 3.6), with a change of -3.1 from baseline (p<0.001). At 12 months, the mean score was 8.7 (SD 3.4), representing a change of -3.7 from baseline (p<0.001).

Regression Analysis

Regression analysis revealed significant associations between environmental factors and changes in rosacea severity over time (Table 5). UV radiation had a coefficient of 0.18 (95% CI 0.10, 0.26; p<0.001), temperature had a coefficient of 0.14 (95% CI 0.08, 0.20; p<0.001), humidity had a coefficient of 0.09 (95% CI 0.03, 0.15; p=0.004), and air pollution had a coefficient of 0.12 (95% CI 0.06, 0.18; p<0.001).

Correlation Analysis

Correlation analysis showed significant associations between environmental factors and specific rosacea symptoms (Table 6). UV radiation was significantly correlated with erythema (r=0.35, p<0.05), flushing (r=0.42, p<0.05), and papules (r=0.28, p<0.05). Temperature was significantly correlated with erythema (r=0.29, p<0.05), flushing (r=0.37, p<0.05), and papules (r=0.24, p<0.05). Humidity was significantly correlated with erythema (r=0.22, p<0.05) and flushing (r=0.26, p<0.05). Air pollution was significantly correlated with erythema (r=0.31, p<0.05), flushing (r=0.34, p<0.05), papules (r=0.27, p<0.05), and pustules (r=0.20, p<0.05).

Subgroup Analysis

Subgroup analysis demonstrated significant improvements in rosacea severity at 12 months across all subgroups (Table 7). Participants aged <40 years had a mean change of -0.9 (SD 0.6, p<0.001), while those aged ≥40 years had a mean change of -0.7 (SD 0.5, p<0.001). Both male and female participants experienced significant improvements, with mean changes of -0.8 (SD 0.5, p<0.001) and -0.8 (SD 0.6, p<0.001), respectively. Participants with erythemato-telangiectatic rosacea had a mean change of -0.9 (SD 0.6, p<0.001), and those with papulopustular rosacea had a mean change of -0.7 (SD 0.5, p<0.001).

Adverse Events

Adverse events were reported by 26% of the participants (Table 8). The most common adverse events were mild skin irritation (12%), temporary redness (8%), and dry skin (6%). No severe adverse events were reported, and 74% of the participants experienced no adverse events during the study period.

Table 1. Baseline Characteristics

Table 2. Environmental Exposure

Table 3. Rosacea Severity Scores

Table 4. Quality of Life Scores

Table 5. Regression Analysis

Table 6. Correlation Coefficients

Table 7. Subgroup Analysis (Rosacea Severity Change at 12 months)

Table 8. Adverse Events

The present observational study investigated the impact of environmental factors on the severity of rosacea symptoms over a period of one year. The results demonstrated that exposure to UV radiation, high temperatures, humidity, and air pollution were significantly associated with increased rosacea severity and worse quality of life scores. These findings are consistent with previous studies that have explored the relationship between environmental factors and rosacea.

A cross-sectional study by Abram et al. found that exposure to UV radiation was significantly associated with the presence of rosacea (odds ratio [OR] 1.25, 95% CI 1.15-1.36, p<0.001)[11]. Similarly, a case-control study by Duman et al. reported that patients with rosacea had significantly higher exposure to UV radiation compared to controls (p<0.001)[12]. Our study further supports these findings, demonstrating a significant correlation between UV radiation and rosacea symptoms, particularly erythema (r=0.35, p<0.05) and flushing (r=0.42, p<0.05).

Temperature and humidity have also been identified as potential triggers for rosacea flare-ups. In a survey-based study by Steinhoff et al., 75% of rosacea patients reported that high temperatures exacerbated their symptoms[13]. Our study found significant correlations between temperature and erythema (r=0.29, p<0.05), flushing (r=0.37, p<0.05), and papules (r=0.24, p<0.05), as well as between humidity and erythema (r=0.22, p<0.05) and flushing (r=0.26, p<0.05).

The role of air pollution in rosacea has been less extensively studied. However, a recent systematic review by Drakaki et al. suggested that exposure to air pollutants, such as particulate matter and nitrogen oxides, may contribute to the development and exacerbation of rosacea[14]. Our study found significant correlations between air pollution and erythema (r=0.31, p<0.05), flushing (r=0.34, p<0.05), papules (r=0.27, p<0.05), and pustules (r=0.20, p<0.05), supporting the potential impact of air pollution on rosacea severity.

Subgroup analyses in our study demonstrated significant improvements in rosacea severity across all age groups, genders, and rosacea subtypes. These findings suggest that the impact of environmental factors on rosacea severity is consistent across various patient subpopulations. However, a study by Tian et al. found that younger age (<30 years) was associated with more severe rosacea symptoms (p=0.03)[15], indicating that age may play a role in rosacea severity.

The adverse events reported in our study were generally mild and transient, with 74% of participants experiencing no adverse events. This is consistent with the findings of a systematic review by van Zuuren et al., which reported that most adverse events associated with rosacea treatments were mild and well-tolerated[16].

This observational study demonstrated that exposure to UV radiation, high temperatures, humidity, and air pollution were significantly associated with increased rosacea severity and reduced quality of life over a one-year period. Subgroup analyses revealed that these associations were consistent across age groups, genders, and rosacea subtypes. The findings highlight the importance of environmental factor management in the treatment and prevention of rosacea flare-ups. Patients should be advised to minimize exposure to identified triggers, use appropriate sun protection, and monitor local environmental conditions to help control their symptoms. Further research is needed to elucidate the specific mechanisms by which environmental factors influence rosacea severity and to develop targeted interventions for reducing the impact of these factors on rosacea patients.

Conflict of interests:The authors declare there are no conflicts of interest.

Financial support and sponsorship:The study was performed with no financial support.

Acknowledgement: We wholeheartedly thank all the study participants for their patience and compliance.

1. Gether L, Overgaard LK, Egeberg A, Thyssen JP. Incidence and prevalence of rosacea: a systematic review and meta-analysis. Br J Dermatol. 2018;179(2):282-289. doi:10.1111/bjd.16481
2. Rainer BM, Fischer AH, Luz Felipe da Silva D, Kang S, Chien AL. Rosacea is associated with chronic systemic diseases in a skin severity-dependent manner: results of a case-control study. J Am Acad Dermatol. 2015;73(4):604-608. doi:10.1016/j.jaad.2015.07.009
3. Moustafa F, Lewallen RS, Feldman SR. The psychological impact of rosacea and the influence of current management options. J Am Acad Dermatol. 2014;71(5):973-980. doi:10.1016/j.jaad.2014.05.036
4. Woo YR, Lim JH, Cho DH, Park HJ. Rosacea: Molecular Mechanisms and Management of a Chronic Cutaneous Inflammatory Condition. Int J Mol Sci. 2016;17(9):1562. doi:10.3390/ijms17091562
5. Steinhoff M, Schauber J, Leyden JJ. New insights into rosacea pathophysiology: a review of recent findings. J Am Acad Dermatol. 2013;69(6 Suppl 1):S15-S26. doi:10.1016/j.jaad.2013.04.045
6. Drakaki E, Dessinioti C, Antoniou CV. Air pollution and the skin. Front Environ Sci. 2014;2:11. doi:10.3389/fenvs.2014.00011
7. Grether-Beck S, Marini A, Jaenicke T, Krutmann J. Photoprotection of human skin beyond ultraviolet radiation. PhotodermatolPhotoimmunol Photomed. 2014;30(2-3):167-174. doi:10.1111/phpp.12111
8. Pillai S, Oresajo C, Hayward J. Ultraviolet radiation and skin aging: roles of reactive oxygen species, inflammation and protease activation, and strategies for prevention of inflammation-induced matrix degradation - a review. Int J Cosmet Sci. 2005;27(1):17-34. doi:10.1111/j.1467-2494.2004.00241.x
9. Jang YH, Sim JH, Kang HY, Kim YC, Lee ES. Immunohistochemical expression of matrix metalloproteinases in the granulomatous rosacea compared with the non-granulomatous rosacea. J EurAcad Dermatol Venereol. 2011;25(5):544-548. doi:10.1111/j.1468-3083.2010.03824.x
10. Casas C, Paul C, Lahfa M, et al. Quantification of Demodex folliculorum by PCR in rosacea and its relationship to skin innate immune activation. Exp Dermatol. 2012;21(12):906-910. doi:10.1111/exd.12030