Increased Risk of Dementia in Patients with Atopic Dermatitis: A Nationwide Population-Based Cohort Study

The A-Z of age-related dermatological diseases

Skin ageing is an inevitable process influenced by both intrinsic and extrinsic factors. Intrinsic aging leads to thinner, drier and less elastic skin with fine wrinkles, while extrinsic factors such as sun exposure, smoking and environmental stresses amplify these changes. Photo-ageing, in particular, causes deep wrinkles, uneven pigmentation and increases the risk of skin cancers. Age-related alterations in skin structure and function include thinning of the epidermis, reduced collagen and elastin and changes in fat distribution, all of which compromise the skin's barrier and mechanical properties. These changes not only increase the susceptibility to conditions such as xerosis, fungal infections and atopic dermatitis but also carry psychological implications. Interestingly, atopic dermatitis, often associated with childhood, has a secondary peak in older adults and may be linked to neurodegenerative conditions such as Alzheimer's disease. This article explores the interplay between skin aging, dermatological diseases, and their broader physical and emotional impacts.

Cumulative Dose Effects of H1 Antihistamine Use on the Risk of Dementia in Patients With Allergic Rhinitis

BACKGROUND

H1 antihistamines (AHs), categorized as first-generation antihistamines (FGAs) or second-generation antihistamines (SGAs), possess anticholinergic properties linked to heightened dementia risk.

OBJECTIVES

To explore dementia risk in patients with allergic rhinitis using AHs.

METHODS

Taiwanese patients with new-onset allergic rhinitis (2011-2017) constituted the study population (677,971 with FGAs or SGAs, 36,081 without AHs). AH use was measured in cumulative defined daily dose (cDDD). Patients were grouped by cDDD (nonuser, <60 cDDD, 60-120 cDDD, and >120 cDDD). A Cox proportional hazard model assessed the AH-dementia association. Sensitivity analysis explored AH effects on dementia risk across subgroups and associations between specific AHs and dementia types.

RESULTS

FGAs in patients with allergic rhinitis were associated with elevated dementia risk. At less than 60 cDDD, adjusted hazard ratio (aHR) was 1.13 (95% CI, 1.09-1.17); at 60 to 120 cDDD, aHR was 1.29 (95% CI, 1.21-1.38); and at more than 120 cDDD, aHR was 1.51 (95% CI, 1.42-1.62). SGAs also raised dementia risk. At less than 60 cDDD, aHR was 1.11 (95% CI, 1.05-1.17); at 60 to 120 cDDD, aHR was 1.19 (95% CI, 1.12-1.26); and at more than 120 cDDD, aHR was 1.26 (95% CI, 1.19-1.33).

CONCLUSIONS

Patients with allergic rhinitis on FGAs or SGAs face an escalating dementia risk with increasing cumulative dosage. Moreover, FGAs exhibit a higher dementia risk compared with SGAs. Nevertheless, extensive clinical trials are imperative for confirming the association between FGA use, SGA use, and dementia risk.

Frequent Occurrence of Alzheimer Disease in Patients With IgE-mediated Allergies

Alzheimer disease and allergic diseases are common health problems. The aim of the study was to check the hypothesis that older patients with IgE-mediated allergies have a higher prevalence of Alzheimer disease. It was a retrospective, multicenter cohort observation. In total, 7129 people were examined, including 3566 women and 2558 men (mean 64.9±6.9 y). The diagnosis of Alzheimer disease is based on the ICD-10 code and appropriate medical documentation. The proportion of patients with confirmed Alzheimer disease in the group of patients with diagnosed allergy compared to the group of those without allergy was as follows: 13.9% (168) versus 8.2% (484) with P=0.001. There was a positive correlation between the presence of Alzheimer disease and high serum total IgE, eosinophilia, and asthma or the presence of atopic polymorphic disease (P<0.05). IgE-dependent allergic diseases, in particular allergic asthma, and the presence of high serum IgE levels may favor the development of Alzheimer disease.

Do Atopic Dermatitis and Psoriasis Have an Impact on Cognitive Decline-Latest Research Review

BACKGROUND

Atopic dermatitis and psoriasis are chronic skin diseases that affect the mental health of patients. The relationship between AD and psoriasis and cognitive processes in patients remains unclear. The aim of the review was to answer the question of whether AD and psoriasis have an impact on cognitive decline in patients.

METHOD

A systematic literature search was conducted on PubMed and EBSCO to identify case-control, cross-sectional, or cohort studies that evaluated the association between atopic dermatitis and psoriasis and cognitive impairment.

RESULTS

Most of the studies included in the review confirmed cognitive decline in patients with atopic dermatitis and psoriasis.

CONCLUSIONS

It seems that atopic dermatitis and psoriasis may negatively affect cognitive processes such as working memory, concentration, attention, and speed of motor reactions. Psychological interventions targeting distorted cognitive processing could improve the quality of life of patients with atopic dermatitis and psoriasis.

Interplay between diabetes mellitus and atopic dermatitis

Inflammatory dermatoses such as atopic dermatitis (AD) have long been linked to the pathogenesis of diabetes mellitus. Indeed, numerous studies show an increased risk of diabetes mellitus in individuals with AD although lower prevalence of diabetes mellitus is also observed in few studies. Though the underlying mechanisms accounting for the reciprocal influence between these two conditions are still unclear, the complex interplay between diabetes mellitus and AD is attributable, in part, to genetic and environmental factors, cytokines, epidermal dysfunction, as well as drugs used for the treatment of AD. Proper management of one condition can mitigate the other condition. In this review, we summarize the evidence of the interaction between diabetes mellitus and AD, and discuss the possible underlying mechanisms by which these two conditions influence each other.

Atopy improves survival and decreases risk of brain metastasis in cutaneous melanoma

Importance

Development of new therapies in melanoma has increased survival, and as a result more patients are living to develop brain metastasis (BrM). Identifying patients at increased risk of BrM is therefore of significant public health importance.

Objective

To determine whether history of atopy is associated with improved survival or reduced incidence of BrM in cutaneous melanoma.

Design

A retrospective cohort study conducted from June 2022 to March 2024.

Setting

Population-based in states with Surveillance, Epidemiology and End Results (SEER) supported cancer registries.

Participants

Individuals (≥65 years) diagnosed with cutaneous melanoma between January 1, 2008 and December 31, 2017 that are participants in traditional Medicare.

Exposures

Individuals were compared that had history of atopy (allergic rhinitis, atopic dermatitis, asthma, and/or allergic/atopic conjunctivitis) diagnosed prior to melanoma diagnosis, ascertained using ICD-9 or ICD-10 codes in Medicare claims.

Main Outcomes and Measures

Primary endpoints were diagnosis with a BrM or death during the follow-up period. Associations between atopy and endpoints were assessed using cox proportional hazards models to estimate hazard ratios (HR) and p-values.

Results

A total of 29,956 cutaneous melanoma cases were identified (median age 76, 60% male and 97% non-Hispanic White). Overall, 7.1% developed BrM during follow up. Among the 35% that had history of atopy, the most common condition was atopic dermatitis (19%). After adjustment for demographic and prognostic factors, atopy was associated with a 16% decrease in death (HR=0.84 [95%CI:0.80-0.87], pFDR<0.001). Among those with non-metastatic disease at time of diagnosis, atopy conferred a 15% decrease in cumulative incidence BrM (HR=0.85 [95%CI: 0.76-0.94], pFDR=0.006), with a 25% decrease associated with atopic dermatitis (HR=0.75 [95%CI:0.65-0.86], pFDR<0.001). Among those with metastatic disease at diagnosis (any metastatic site), only those who received immune checkpoint inhibitors had a survival benefit associated with atopy (HR=0.31, [95%CI:0.15-0.64], p=0.001 vs HR=1.41, [95%CI:0.87-2.27], p=0.165).

Conclusions and Relevance

Atopy, particularly atopic dermatitis, was significantly associated with improved survival and decreased incidence of BrM. The improved survival associated with these conditions in the context of immunotherapy suggests that these conditions in the elderly may identify those with more robust immune function that may be more responsive to treatment.

Causal Association Between Allergic Diseases and Dementia: Evidence from Multivariate Mendelian Randomization Study

Background

The link between allergic diseases and dementia remains controversial, and the genetic causality of this link is unclear.

Objective

This study investigated the causal relationship between allergic diseases and dementia using univariate and multivariate Mendelian randomization (MR) methods.

Methods

We selected genome-wide association studies including 66,645 patients with allergic diseases and 12,281 patients with dementia, with statistical datasets derived from the FinnGen Consortium of European origin. After a rigorous screening process for single nucleotide polymorphisms to eliminate confounding effects, MR estimation was performed mainly using the inverse variance weighting method and the MR-Egger method. Sensitivity analyses were performed using Cochran's Q test, MR-PRESSO test, MR Pleiotropy residuals and leave-one-out analysis.

Results

Univariate and multivariate MR together demonstrated a causal relationship between atopic dermatitis and reduced vascular dementia (VaD) risk (OR = 0.89, 95% CI: 0.81-0.99, p = 0.031; OR = 0.85, 95% CI: 0.76-0.95, p = 0.003). MVMR confirmed asthma was associated with a reduction in the risk of Alzheimer's disease (AD) (OR = 0.82, 95% CI: 0.71-0.94, p = 0.005) and may be associated with a reduction in the risk of VaD (OR = 0.80, 95% CI: 0.65-0.99, p = 0.042); allergic rhinitis may be causally associated with an increased risk of AD (OR = 1.16, 95% CI: 1.00-1.35, p = 0.046) and VaD (OR = 1.29, 95% CI: 1.03-1.62, p = 0.027). In sensitivity analyses, these findings were reliable.

Conclusions

MR methods have only demonstrated that allergic rhinitis dementia is associated with an increased risk of developing dementia. Previously observed associations between other allergic diseases and dementia may be influenced by comorbidities and confounding factors rather than causality.

Improvement in Cutaneous Conditions Can Benefit Some Health Conditions in the Elderly

As we are aging, a number of cutaneous and extracutaneous disorders will be developed. Although the pathogenesis of these aging-associated disorders is not clear yet, abnormalities in the skin are linked to some aging-associated disorders at least to some extent. Inflammatory dermatoses such as psoriasis and atopic dermatitis predispose to the development of cardiovascular diseases, obesity and type 2 diabetes. In addition, both chronologically aged skin and individuals with some aging-associated systemic conditions display altered epidermal function, such as reduced stratum corneum hydration levels, which can provoke cutaneous inflammation. Because aged skin exhibits higher expression levels of inflammatory cytokines, which play a pathogenic role in a variety of aging-associated health condition, the association of the skin with some aging-associated disorders is likely mediated by inflammation. This postulation is supported by the evidence that improvement in either epidermal function or inflammatory dermatoses can mitigate some aging-associated disorders such as mild cognitive impairment and insulin sensitivity. This perspective discusses the association of the skin with aging-associated disorders and highlights the potential of improvement in cutaneous conditions in the management of some health conditions in the elderly.