Classifying atopic dermatitis: a systematic review of phenotypes and associated characteristics

Atopic dermatitis is a heterogeneous disease, accompanied by a wide variation in disease presentation and the potential to identify many phenotypes that may be relevant for prognosis and treatment. We aimed to systematically review previously reported phenotypes of atopic dermatitis and any characteristics associated with them. Ovid EMBASE, Ovid MEDLINE and Web of Science were searched from inception till the 12th of February 2021 for studies attempting to classify atopic dermatitis. Primary outcomes are atopic dermatitis phenotypes and characteristics associated with them in subsequent analyses. A secondary outcome is the methodological approach used to derive them. In total, 8,511 records were found. By focusing only on certain clinical phenotypes, 186 studies were eligible for inclusion. The majority of studies were hospital-based (59%, 109/186) and cross-sectional (76%, 141/186). The number of included patients ranged from seven to 526,808. Data-driven approaches to identify phenotypes were only used in a minority of studies (7%, 13/186). Ninety-one studies (49%) investigated a phenotype based on disease severity. A phenotype based on disease trajectory, morphology and eczema herpeticum was investigated in 56 (30%), 22 (12%) and 11 (6%) studies, respectively. Thirty-six studies (19%) investigated morphological characteristics in other phenotypes. Investigated associated characteristics differed between studies. In conclusion, we present an overview of phenotype definitions used in literature for severity, trajectory, morphology and eczema herpeticum, including associated characteristics. There is a lack of uniform and consistent use of atopic dermatitis phenotypes across studies.

Inflammatory skin diseases and the risk of chronic kidney disease: population-based case-control and cohort analyses

BACKGROUND

Emerging evidence suggests an association between common inflammatory skin diseases and chronic kidney disease (CKD).

OBJECTIVES

To explore the association between CKD stages 3-5 (CKD3-5) and atopic eczema, psoriasis, rosacea and hidradenitis suppurativa.

METHODS

We undertook two complementary analyses; a prevalent case-control study and a cohort study using routinely collected primary care data [UK Clinical Practice Research Datalink (CPRD)]. We matched individuals with CKD3-5 in CPRD in March 2018 with up to five individuals without CKD for general practitioner practice, age and sex. We compared the prevalence of CKD3-5 among individuals with and without each inflammatory skin disease. We included individuals in CPRD with diabetes mellitus (2004-2018) in a cohort analysis to compare the incidence of CKD3-5 among people with and without atopic eczema and psoriasis.

RESULTS

Our study included 56 602 cases with CKD3-5 and 268 305 controls. Cases were more likely than controls to have a history of atopic eczema [odds ratio (OR) 1·14, 99% confidence interval (CI) 1·11-1·17], psoriasis (OR 1·13, 99% CI 1·08-1·19) or hidradenitis suppurativa (OR 1·49, 99% CI 1·19-1·85), but were slightly less likely to have been diagnosed with rosacea (OR 0·92, 99% CI 0·87-0·97), after adjusting for age, sex, practice (matching factors), index of multiple deprivation, diabetes, smoking, harmful alcohol use and obesity. Results remained similar after adjusting for hypertension and cardiovascular disease. In the cohort with diabetes (N = 335 827), there was no evidence that CKD3-5 incidence was associated with atopic eczema or psoriasis.

CONCLUSIONS

Atopic eczema, psoriasis and hidradenitis suppurativa are weakly associated with CKD3-5. Future research is needed to elucidate potential mechanisms and the clinical significance of our findings.

Atopic eczema and obesity: a population-based study

BACKGROUND

Atopic eczema is a common chronic inflammatory skin disease. Research suggests an association between atopic eczema and obesity, with inconsistent evidence from European populations.

OBJECTIVES

To explore the association between diagnosed atopic eczema and being overweight or obese, and whether increased atopic eczema severity was associated with higher body mass index.

METHODS

We undertook a cross-sectional analysis within a cohort of adults (matched by age, sex and general practice) with and without a diagnosis of atopic eczema. We used primary care (Clinical Practice Research Datalink Gold) and linked hospital admissions data (1998-2016). We used conditional logistic regression to compare the odds of being overweight or obese (adjusting for confounders and potential mediators) in those with atopic eczema (mild, moderate and severe, and all eczema) vs. those without.

RESULTS

We identified 441 746 people with atopic eczema, matched to 1 849 722 without. People with atopic eczema had slightly higher odds of being overweight or obese vs. those without [odds ratio (OR) 1·08, 95% confidence interval (CI) 1·07-1·09] after adjusting for age, asthma and socioeconomic deprivation. Adjusting for potential mediators (high-dose glucocorticoids, harmful alcohol use, anxiety, depression, smoking) had a minimal impact on effect estimates (OR 1·07, 95% CI 1·06-1·08). We saw no evidence that odds of being overweight or obese increased with increasing atopic eczema severity, and there was no association in people with severe eczema.

CONCLUSIONS

We found evidence of a small overall association between atopic eczema and being overweight or obese. However, there was no association with obesity among those with the most severe eczema. Our findings are largely reassuring for this prevalent patient group who may already have an increased risk of cardiovascular disease.

The association between partner bereavement and melanoma: cohort studies in the U.K. and Denmark

BACKGROUND

Psychological stress is commonly cited as a risk factor for melanoma, but clinical evidence is limited.

OBJECTIVES

This study aimed to evaluate the association between partner bereavement and (i) first-time melanoma diagnosis and (ii) mortality in patients with melanoma.

METHODS

We conducted two cohort studies using data from the U.K. Clinical Practice Research Datalink (1997-2017) and Danish nationwide registries (1997-2016). In study 1, we compared the risk of first melanoma diagnosis in bereaved vs. matched nonbereaved people using stratified Cox regression. In study 2 we estimated hazard ratios (HRs) for death from melanoma in bereaved compared with nonbereaved individuals with melanoma using Cox regression. We estimated HRs separately for the U.K. and for Denmark, and then pooled the data to perform a random-effects meta-analysis.

RESULTS

In study 1, the pooled adjusted HR for the association between partner bereavement and melanoma diagnosis was 0·88 [95% confidence interval (CI) 0·84-0·92] across the entire follow-up period. In study 2, we observed increased melanoma-specific mortality in people experiencing partner bereavement across the entire follow-up period (HR 1·17, 95% CI 1·06-1·30), with the peak occurring during the first year of follow-up (HR 1·31, 95% CI 1·07-1·60).

CONCLUSIONS

We found decreased risk of melanoma diagnosis, but increased mortality associated with partner bereavement. These findings may be partly explained by delayed detection resulting from the loss of a partner who could notice skin changes. Stress may play a role in melanoma progression. Our findings indicate the need for a low threshold for skin examination in individuals whose partners have died. What is already known about this topic? Psychological stress has been proposed as a risk factor for the development and progression of cancer, including melanoma, but evidence is conflicting. Clinical evidence is limited by small sample sizes, potential recall bias associated with self-report, and heterogeneous stress definitions. What does this study add? We found a decreased risk of melanoma diagnosis, but increased mortality associated with partner bereavement. While stress might play a role in the progression of melanoma, an alternative explanation is that bereaved people no longer have a close person to help notice skin changes, leading to delayed melanoma detection. Linked Comment: Talaganis et al. Br J Dermatol 2020; 183:607-608.

Partner bereavement and risk of psoriasis and atopic eczema: cohort studies in the U.K. and Denmark

BACKGROUND

Stress is commonly cited as a risk factor for psoriasis and atopic eczema, but such evidence is limited.

OBJECTIVES

To investigate the association between partner bereavement (an extreme life stressor) and psoriasis or atopic eczema.

METHODS

We conducted cohort studies using data from the U.K. Clinical Practice Research Datalink (1997-2017) and Danish nationwide registries (1997-2016). The exposed cohort was partners who experienced partner bereavement. The comparison cohort was up to 10 nonbereaved partners, matched to each bereaved partner by age, sex, county of residence (Denmark) and general practice (U.K.). Outcomes were the first recorded diagnosis of psoriasis or atopic eczema. We estimated hazard ratios (HRs) and confidence intervals (CIs) using a stratified Cox proportional hazards model in both settings, which were then pooled in a meta-analysis.

RESULTS

The pooled adjusted HR for the association between bereavement and psoriasis was 1·01 (95% CI 0·98-1·04) across the entire follow-up. Similar results were found in other shorter follow-up periods. Pooled adjusted HRs for the association between bereavement and atopic eczema were 0·97 (95% CI 0·84-1·12) across the entire follow-up, 1·09 (95% CI 0·86-1·38) within 0-30 days, 1·18 (95% CI 1·04-1·35) within 0-90 days, 1·14 (95% CI 1·06-1·22) within 0-365 days and 1·07 (95% CI 1·02-1·12) within 0-1095 days.

CONCLUSIONS

We found a modest increase in the risk of atopic eczema within 3 years following bereavement, which peaked in the first 3 months. Acute stress may play a role in triggering onset of new atopic eczema or relapse of atopic eczema previously in remission. We observed no evidence for increased long-term risk of psoriasis and atopic eczema following bereavement.