The effects of season and weather on healthcare utilization among patients with atopic dermatitis.

BACKGROUND: Patient-reported triggers for atopic dermatitis (AD) flares include changes in ultraviolet irradiation, humidity and temperature. OBJECTIVES: To identify the relationships between weather data and healthcare utilization in AD patients. METHODS: Using nationwide healthcare registries, clinic (1994-2012) and hospital visits (1977-2012) for AD treatment were calculated as well as monthly totals of topical corticosteroid (TCS) (1996-2012) and calcineurin inhibitor (TCI) prescriptions (2003-20012) filled by AD patients. We calculated monthly averages of temperature, atmospheric pressure, cloud cover and hours of bright sunlight and compared these variables to healthcare utilization endpoints, for the years 2000-2012 (n = 156 months), using linear regression models. RESULTS: In Denmark, between the year 2000 and 2012, mean monthly totals of AD emergency room visits were 6, AD hospitalizations 32, AD outpatient visits 170, TCS prescriptions filled by AD patients 3811 and TCI prescriptions 2552. Healthcare utilization among AD patients was highest in winter/spring. Temperature was the environmental variable that had the strongest association with healthcare utilization: per 1°C lower monthly temperature, 2 more (95% confidence interval [CI] 1-4) AD clinic/hospital visits hospitalizations were observed, 18 (95% CI 9-26) more TCS prescriptions and 53 (95% CI 36-70) more TCI prescriptions were filled by patients with AD. Environmental variables were highly correlated. Associations between AD healthcare utilization and hours of cloud cover were generally positive, while those with hours of bright sunlight were generally inverse. CONCLUSIONS: AD healthcare utilization markers changed significantly with season. A decline in temperature correlated well with AD patients' healthcare utilization, but a causative role could not be determined with certainty.

Changes in filaggrin degradation products and corneocyte surface texture by season.

BACKGROUND: During the winter in northern countries, the risk of dermatitis is increased due to low temperature and humidity. Dermatitis is particularly common on weather-exposed skin such as the cheeks and hands. Recently, increased numbers of unidentified nanosized protrusions on the corneocyte surface were associated with dermatitis and deficiency of natural moisturizing factor (NMF). OBJECTIVES: To investigate the effect of season on NMF levels and corneocyte surface texture in cheek and hand skin of healthy adults. METHODS: Eighty healthy volunteers (40 male and 40 female) were recruited: 40 aged 18-40 years and 40 aged ≥ 70 years. Cheek and dorsal hand skin was tape stripped in the winter and summer. Analysis for NMF and corneocyte surface texture was done (Dermal Texture Index, DTI). Potential confounders were registered and adjusted for. RESULTS: In cheek skin, NMF levels were reduced and DTI elevated during the winter compared with the summer. Older participants had higher NMF levels than younger participants. In the summer, DTI level was dependent on self-reported ultraviolet exposure. In hand skin, NMF levels were higher during the winter than in the summer, and female participants had higher NMF levels than male participants. CONCLUSIONS: Seasonal effects on NMF and DTI on the cheeks and hands were found, suggesting an influence of climatic factors at the biochemical and ultrastructural levels. Significant variations were also observed regarding age and sex, making it difficult to draw firm conclusions. Our study adds new pieces to the puzzle of seasonal differences in xerosis and dermatitis.

Effect of atopic skin stressors on natural moisturizing factors and cytokines in healthy adult epidermis.

BACKGROUND: Epidermal deficiency of filaggrin, and the derived natural moisturizing factors (NMFs), is associated with increased risk of atopic dermatitis (AD). While filaggrin gene mutations cause filaggrin deficiency, there is limited insight into the causative environmental factors. OBJECTIVES: To explore the effect of selected exogenous skin stressors on NMF and skin cytokine levels in healthy adult epidermis. METHODS: Forty healthy volunteers (aged 18-49 years) were exposed to hard, soft and chlorinated water, 0·5% sodium lauryl sulfate, house dust mite, cat allergen, staphylococcal enterotoxin B (SEB), cooling and histamine. Participants were tape-stripped and biophysiological measurements performed. NMF was determined after 24 and 48 h, whereas skin cytokines were measured after 24 h for selected exposures. RESULTS: At 24 h, a significant decrease in NMFs was observed for soft (0·51 ± 0·19 g m-2 h-1 ) and hard water (0·61 ± 0·32 g m-2 h-1 ) compared with occlusion alone (0·71 ± 0·18 g m-2 h-1 ). Hard water led to increased levels of interleukin (IL)-4, interferon (IFN)-γ and IL-10. Exposure to house dust mite and SEB led to a significant decrease in NMFs after 24 h (0·77 ± 0·28 and 0·80 ± 0·28 g m-2 h-1 , respectively) compared with occlusion alone (1·00 ± 0·42 g m-2 h-1 ). House dust mite led to an increase in IFN-γ, IL-2 and IL-4 vs. the nonoccluded control site. CONCLUSIONS: Based on experimental exposure to selected atopic skin stressors, we conclude that NMFs levels are decreased along with increased secretion of various skin cytokines in healthy individuals. Our data highlight environmental factors that might play a role in AD pathophysiology.

Concentration of filaggrin monomers, its metabolites and corneocyte surface texture in individuals with a history of atopic dermatitis and controls.

BACKGROUND: Atopic dermatitis (AD) is characterized by skin barrier dysfunction. Notably, a high number of nano-scale protrusions on the surface of corneocytes, which can be expressed by the Dermal Texture Index (DTI), were recently associated with paediatric AD, loss-of-function mutations in filaggrin gene (FLG) and reduced levels of natural moisturizing factors (NMF). No study has so far examined the association between these parameters and monomeric filaggrin levels in adults. OBJECTIVE: To determine DTI, monomeric filaggrin and NMF in healthy controls and a group of patients with controlled dermatitis. METHODS: A total of 67 adults (20 healthy controls and 47 dermatitis patients) were included. In the patient population, a personal history of AD was diagnosed by the U.K. Working Party's Diagnostic Criteria. All participants were tested for FLG mutations (R501X, 2282del4, R2447X). Transepidermal water loss, monomeric filaggrin, DTI and NMF were measured. RESULTS: In the patient population, 78.7% (37/47) had a history of AD and 59.5% (28/47) had FLG mutations. Patients had significantly higher levels of DTI and significantly lower levels of monomeric filaggrin and NMF compared to the 20 healthy controls. Among patients, reduced level of monomeric filaggrin and NMF correlated with the presence of FLG mutations and clinical phenotypes such as xerosis, palmar hyperlinearity and AD. Among healthy controls, DTI was significantly higher in the oldest age group compared to the two younger age groups. CONCLUSION: A significant difference in DTI, monomeric filaggrin and NMF levels was found when comparing dermatitis patients with healthy controls. These findings suggest that even mild dermatitis or non-visible inflammation has a significant and negative effect on the skin barrier as inflammation is known to reduce filaggrin levels. DTI was significantly increased in aged individuals in the healthy control group, suggesting a gradual change in corneocyte morphology with age.

The association between atopic dermatitis and hand eczema: a systematic review and meta-analysis.

BACKGROUND: Atopic dermatitis (AD) and hand eczema (HE) are common chronic and relapsing inflammatory skin conditions that often co-occur. OBJECTIVES: While several studies have addressed their relationship, the exact association estimate is unknown. METHODS: We systematically reviewed published literature on the association between AD and HE in PubMed, Embase and Web of Science using the following search terms: (atopic dermatitis OR atopic eczema) AND (hand dermatitis OR hand eczema). Meta-analyses were then performed to examine the association between AD and the point, 1-year and lifetime prevalence of HE, respectively. RESULTS: We identified 35 relevant studies, of which 26 were included in the meta-analyses. AD was associated with an increased prevalence of HE with regard to point [odds ratio (OR) 2·35; 95% confidence interval (CI) 1·47-3·76], 1-year (OR 4·29; 95% CI 3·13-5·88) and lifetime prevalence (OR 4·06; 95% CI 2·72-6·06). Furthermore, positive associations between AD and occupational HE were identified when assessing the 1-year (OR 4·31; 95% CI 2·08-8·91) and lifetime prevalence (OR 2·81; 95% CI 2·08-3·79). Similar positive associations were found in the general population studies, i.e. OR 4·19 (95% CI 3·46-5·08) and OR 5·69 (95% CI 4·41-7·36). CONCLUSIONS: Important study limitations include the wide use of questionnaire studies, and lack of prospective studies as well as poor clinical phenotype descriptions. In conclusion, our systematic review and meta-analysis showed that patients with AD had a strongly increased prevalence of HE. Clinicians should continue to guide patients with AD away from occupations with a high risk of HE.

Skin absorption through atopic dermatitis skin: a systematic review.

Patients with atopic dermatitis (AD) have skin barrier impairment in both lesional and nonlesional skin. They are typically exposed daily to emollients and intermittently to topical anti-inflammatory medicaments, thereby increasing the risk of developing contact allergy and systemic exposure to chemical ingredients found in these topical preparations. We systematically searched for studies that investigated skin absorption of various penetrants, including medicaments, in patients with AD, but also in animals with experimentally-induced dermatitis. We identified 40 articles: 11 human studies examining model penetrants, 26 human studies examining AD drugs, and three animal studies. We conclude that patients with AD have almost twofold increased skin absorption compared with healthy controls. There is a need for well-designed epidemiological and dermatopharmacokinetic studies that examine to what extent AD causes patients to be systemically exposed to chemicals compared with nonatopic dermatitis.

Determination of natural moisturizing factors in the skin: Raman microspectroscopy versus HPLC.

BACKGROUND: Natural moisturizing factor (NMF) is used as genotypic and phenotypic biomarker in diagnostics. This study is a side-to-side comparison of two different methods to determine NMF in atopic dermatitis patients: Raman microspectroscopy and stratum corneum tape stripping followed by HPLC. RESULTS: Measured NMF values were significantly correlated (R2 = .61; p < .0001), both methods demonstrated a concentration-depth dependence of NMF and reduced NMF levels in the carriers of filaggrin null mutations. Good agreement between measurements of left and right arms indicated robustness and good reproducibility of both methods. CONCLUSIONS: Both methods showed comparable performance, choice of method will rather be influenced by practical consideration.

The effect of environmental humidity and temperature on skin barrier function and dermatitis.

Physicians are aware that climatic conditions negatively affect the skin. In particular, people living in equator far countries such as the Northern parts of Europe and North America are exposed to harsh weather during the winter and may experience dry and itchy skin, or deterioration of already existing dermatoses. We searched the literature for studies that evaluated the mechanisms behind this phenomenon. Commonly used meteorological terms such as absolute humidity, relative humidity and dew point are explained. Furthermore, we review the negative effect of low humidity, low temperatures and different seasons on the skin barrier and on the risk of dermatitis. We conclude that low humidity and low temperatures lead to a general decrease in skin barrier function and increased susceptible towards mechanical stress. Since pro-inflammatory cytokines and cortisol are released by keratinocytes, and the number of dermal mast cells increases, the skin also becomes more reactive towards skin irritants and allergens. Collectively, published data show that cold and dry weather increase the prevalence and risk of flares in patients with atopic dermatitis.

Xerosis is associated with asthma in men independent of atopic dermatitis and filaggrin gene mutations.

BACKGROUND: Epidermal filaggrin deficiency due to common filaggrin gene (FLG) mutations causes xerosis and strongly increases the risk of atopic dermatitis and even asthma. However, it is unknown whether xerosis independent of FLG mutations could also increase the risk of asthma. OBJECTIVE: To evaluate whether generalized xerosis was associated with asthma, independent of atopic dermatitis and common FLG mutations in a cross-sectional study on adult Danes. METHODS: A total of 3396 adults from the general population participated in a health examination. Lung function and serum-specific IgE levels to inhalant allergens were measured and information on xerosis and atopic diseases was obtained by means of a questionnaire. Participants were genotypes for the three most common FLG mutations in Northern Europeans: R501X, 2282del4 and R2447X. RESULTS: Fully adjusted logistic regression analyses showed that asthma (either current or at some point in life) was significantly associated with reporting generalized xerosis (OR 1.32; 95% CI 1.02-1.72). The association was stronger in men (OR 1.79; 95% CI 1.13-2.84) when compared to women (OR 1.18; 95% CI 0.86-1.62). Furthermore, a significant association was observed between xerosis and 'allergic asthma' in men (OR 2.13; 95% CI 1.08-4.19). CONCLUSION: Our findings indicate an association between xerosis and asthma in men independent of atopic dermatitis and FLG mutations. Both facilitated allergen sensitization and secondary degradation of filaggrin following T-helper cell 2 inflammation might be key elements to understanding this relationship.