Rapid identification of primary atopic disorders (PAD) by a clinical landmark-guided, upfront use of genomic sequencing.

Primary atopic disorders (PAD) are monogenic disorders caused by pathogenic gene variants encoding proteins that are key for the maintenance of a healthy skin barrier and a well-functioning immune system. Physicians face the challenge to find single, extremely rare PAD patients/families among the millions of individuals with common allergic diseases. We describe case scenarios with signature PAD. We review the literature and deduct specific clinical red flags for PAD detection. They include a positive family history and/or signs of pathological susceptibility to infections, immunodysregulation, or syndromic disease. Results of conventional laboratory and most immunological lab studies are not sufficient to make a definitive diagnosis of PAD. In the past, multistep narrowing of differential diagnoses by various immunological and other laboratory tests led to testing of single genes or gene panel analyses, which was a time-consuming and often unsuccessful approach. The implementation of whole-genomic analyses in the routine diagnostics has led to a paradigm shift. Upfront genome-wide analysis by whole genome sequencing (WGS) will shorten the time to diagnosis, save patients from unnecessary investigations, and reduce morbidity and mortality. We propose a rational, clinical landmark-based approach for deciding which cases pass the filter for carrying out early WGS. WGS result interpretation requires a great deal of caution regarding the causal relationship of variants in PAD phenotypes and absence of proof by adequate functional tests. In case of negative WGS results, a re-iteration attitude with re-analyses of the data (using the latest data base annotation)) may eventually lead to PAD diagnosis. PAD, like many other rare genetic diseases, will only be successfully managed, if physicians from different clinical specialties and geneticists interact regularly in multidisciplinary conferences.

[Causality between atopic diseases and osteoarthritis:a Mendelian randomization study].

OBJECTIVE: To explore causal relationship between atopic diseases (asthma and atopic dermatitis) and osteoarthritis (OA) by using mendelian randomization(MR). METHODS: Asthma and atopic dermatitis as instrumental variables were selected, searched them through IEU database, and selected the latest data with a large number of cases and single nucleotide polymorphism (SNP). Data were collected and processed using R language, inverse varianceweighted (IVW) method was adopted as main MR Evaluation method. Single linear regression was performed to estimate causality based on pooled knee and hip data from genome-wide association studies (GWAS). The forest map was drawn to visualize the results, and gene pleiotropy and sensitivity were analyzed by scatter plot and funnel plot. At the same time, asthma, atopic dermatitis, body mass index (BMI), osteoporosis and OA were selected for multivariate MR Analysis to exclude the effect of horizontal pleiotropy on the results in GWAS data. RESULTS: Analysis of MR-IVW results showed asthma was positively correlated with causal effect of OA [OR=1.41, 95%CI(1.07, 1.85), P=0.02], multivariate Mendelian randomization (MVMR) adjusted for BMI and osteoporosis and a direct causal effect on OA was observed [OR=1.57, 95%CI(1.03, 2.39), P=0.03)]. MR Results of two samples of atopic dermatitis and OA were [OR=1.01, 95%CI(0.97, 1.04), P=0.76], and MVMR results were [OR=1.02, 95%CI(0.99, 1.05), P=0.25], indicating no clear causal relationship between two samples. CONCLUSION: Asthma could increase risk of OA, atopic dermatitis has no obvious relationship with OA, and the relationship between atopic diseases and OA still needs to be discussed.

Successful treatment of the dupilumab-induced psoriatic dermatitis/arthritis and atopic dermatitis with a JAK inhibitor: A case report and literature review.

Dupilumab-induced psoriatic dermatitis and arthritis in a patient with atopic dermatitis were effectively managed with upadacitinib, highlighting the use of Janus kinase inhibitors as a possible treatment for biologic therapy side effects.

A Fleshy Mystery: Prurigo Nodularis.

Prurigo nodularis is a chronic dermatologic condition typically presenting as firm, dome-shaped pruritic nodules of various sizes that are often symmetrically distributed on extensor surfaces of the extremities. The diagnosis is clinical and based on a history of chronic, severe pruritis in the setting of characteristic, excoriated lesions. Treatment is difficult and aimed at reducing skin irritation and pruritus. Quality of life is impacted due to the chronic, intractable, and relapsing nature of the disease. Here, we report a case of prurigo nodularis diagnosed in the outpatient clinic setting. This paper aims to report the patient's clinical history, presentation, and histopathologic findings, as well as present a literature review to determine the significance of this case and the approach to ongoing management.

Atopic diseases-Diagnostics, mechanisms, and exposures.

Epidemiological data suggest that atopic diseases begin in early life and that most cases present clinically during early childhood. The diseases are highly prevalent and increase as communities adopt western lifestyles. Disentangling the pathophysiological mechanisms leading to disease debut is necessary to identify beneficial/harmful exposures so that successful prevention and treatment can be generated. The objective of this review is to explore the definition of atopy and mechanisms of atopic diseases, and to investigate the importance of environmental factors in early life, prior to disease development. First, the distribution of sIgE levels in children is investigated, as this is one of the main criteria for the definition of atopy. Thereafter, it is explored how studies of parental atopic status, sensitization patterns, and early debut and severity of atopic dermatitis have substantiated the theory of an early-life window of opportunity for intervention that precedes the development of atopic diseases in childhood. Then, it is examined whether early-life exposures such as breastfeeding, dogs, cats, and house dust mites in the home perinatally constitute important influencers in this crucial time of life. Finally, it is discussed how these findings could be validated in randomized controlled trials, which might prepare the ground for improved diagnostics and prevention strategies to mitigate the current atopic pandemic.

Epidemiology and Racial Differences of EoE Patients in a U.S. Veterans Population.

BACKGROUND: Eosinophilic esophagitis (EoE) is increasing in prevalence but there is a lack of population-based studies. We sought to determine the prevalence, demographics, and associated atopic diseases in the Veterans Affairs (VA) population. METHODS: A nationwide analysis of data from the VA patient population was done using a Veterans Health Administration database. EoE was identified using ICD9 (530.13) and ICD10 (K20.0) codes from October 2008 to June 2020. Demographic data, smoking status, BMI, treatment, and ICD codes for atopic diagnoses were collected. Two sample proportion z-tests, Chi-square tests, two-sample t tests, and one-way ANOVA were used to assess associations across demographic categories. RESULTS: We identified a total of 11,775 patients with an EoE diagnosis: 91% male, 83% White, 8.6% Black, and 5% were of Hispanic ethnicity. The prevalence of EoE increased over time. At diagnosis, the mean age was 48.5 years overall, 51.6 years for Black patients, 45.3 years for Hispanic patients, and 48.2 years for Whites. Dysphagia was the most common symptom overall, but a higher percentage of Blacks and females were found to report chest pain (p < 0.0001, h = 0.32). With the exception of urticaria and atopic dermatitis, both Blacks and Hispanics had a higher incidence of atopic conditions compared to other races and ethnicities (p < 0.0001). CONCLUSION: While EoE is seen primarily in White males, our study shows that a notable percentage of patients were Black or Hispanic, suggesting that EoE should be considered in non-white patients. The later age of diagnosis in this group could represent a lack of awareness about EoE among non-white patients. More research is needed to study these associations.

Biologic Therapies across Nasal Polyp Subtypes.

Chronic rhinosinusitis with nasal polyposis is a common inflammatory condition, with subtypes like aspirin-exacerbated respiratory disease, allergic fungal rhinosinusitis, and central compartment atopic disease sharing a common type 2 inflammatory pathway. Respiratory biologic therapies have been developed that target type 2 inflammation. In this article, we discuss the use of respiratory biologic therapies for nasal polyposis in general, as well as within the various subtypes of nasal polyps. Further, we discuss future roles of novel biologic therapies targeting type 2 inflammation in nasal polyposis.

Yeast-Derived Nucleotides Enhance Fibroblast Migration and Proliferation and Provide Clinical Benefits in Atopic Dermatitis.

Nucleotides, glycosaminoglycans, and omega-3 essential fatty acids (O3s) could be used for improving skin health, although their modes of action, alone or in combination, are not yet fully understood. To gain some insight into these mechanisms, we performed two in vitro tests and one in vivo pilot trial. The effects on human dermal fibroblast proliferation and migration were evaluated with the following compounds and combinations: 0.156 mg/mL O3s, 0.0017 mg/mL hyaluronic acid (HA), 0.0004 mg/mL dermatan sulfate (DS), 0.0818 mg/mL nucleotides, and [O3s + HA + DS] and [O3s + HA + DS + nucleotides] at the same concentrations. In both in vitro assays, adding nucleotides to [O3s + HA + DS] provided significant improvements. The resulting combination [O3s + HA + DS + nucleotides] was then tested in vivo in dogs with atopic dermatitis by oral administration of a supplement providing a daily amount of 40 mg/kg nucleotides, 0.9 mg/kg HA, 0.18 mg/kg DS, 53.4 mg/kg EPA, and 7.6 mg/kg DHA. After 30 days, the pruritus visual analog scale (pVAS) score was significantly reduced, and no adverse effects were observed. In conclusion, the combination of nucleotides plus glycosaminoglycans and O3s could serve as a useful therapeutic alternative in skin health applications.

Endoscopic and Radiologic Central Compartment Disease as Predictors of Perennial Inhalant Allergen Sensitization in Chronic Rhinosinusitis.

BACKGROUND: Central compartment atopic disease (CCAD) is a recently described variant of chronic rhinosinusitis (CRS) strongly associated with atopy. The association between central compartment disease (CCD) and inhalant allergy is not well established in South-East Asia, where perennial allergic rhinitis is common. OBJECTIVES: The primary objective was to evaluate endoscopic and radiologic CCD as predictors of perennial allergen sensitization in primary CRS. The secondary objective was to compare clinical characteristics of CCAD with other CRS subtypes (CRSwNP and CRSsNP). METHODS: A retrospective study of consecutive patients with primary CRS who underwent endoscopic sinus surgery at our institution was performed. Allergen sensitization was confirmed by skin or serum testing. Endoscopy records and computed tomography scans of paranasal sinuses were reviewed for CCD. The diagnostic accuracy of endoscopic and radiologic CCD in predicting atopy was calculated. RESULTS: There were 104 patients (43 CCAD, 30 CRSwNP and 31 CRSsNP). Endoscopic CCD was significantly associated with aeroallergen sensitization (odds ratio (OR) 3.99, 95% confidence interval (CI) 1.65-9.67, P = 0.002). Endoscopic CCD predicted atopy with 57% sensitivity, 72% specificity, 69% positive predictive value and positive likelihood ratio of 2.05. Radiologic CCD was not associated with aeroallergen sensitization (OR 0.728, 95%CI 0.292-1.82, P = 0.496). There were more CCAD patients who reported hyposmia (86% vs 42%, P < 0.001) and had anosmia on olfactory testing than CRSsNP (65% vs 14%, P = 0.015). The prevalence of atopy was significantly higher in CCAD than CRSwNP and CRSsNP (70% vs 37% and 42%, P = 0.015 and P = 0.05, respectively). Median serum total immunoglobulin E was higher in CCAD (283 IU/ml) and CRSwNP (127 IU/ml) than CRSsNP (27 IU/ml, P = 0.006 and P = 0.042, respectively). CONCLUSIONS: Endoscopic CCD was a better predictor of inhalant allergy than radiologic CCD in primary CRS, in a locale of perennial allergic rhinitis.

Associations between diet diversity during infancy and atopic disease in later life: Systematic review.

Background: The incidence of allergic disease remains high, and many studies have focused on the association between food diversity in infancy and allergic disease later in life, but their conclusions are still controversial. Objective: We aimed to synthesize the literature on the association between childhood diet diversity and atopic disease. Methods: We searched the PubMed, Cochrane Library, Embase, Scopus, VPCS, and Wanfang databases for studies about food diversity and atopic disease. Seventeen high-quality studies, 14 cohort studies, and 1 case-control study were included from 5244 studies with sample sizes ranging from 100 to 5225. Results: All high-quality cohort studies showed that increasing food diversity in infancy can effectively prevent the occurrence of food allergies (5/5). Moderate evidence showed that increased food diversity reduced the risk of asthma (4/6), food sensitization (3/5), and atopic dermatitis (3/5). However, its effect on eczema (5), allergic rhinitis (4), and other diseases remains controversial. Conclusions: Increasing food diversity during infancy is a potential method for preventing food allergy, asthma, atopic dermatitis, and food sensitization later in life. There is little or no comparative evidence about the protective effect of food diversity on other atopic diseases.

Atopic dermatitis phenotype affects expression of atopic diseases despite similar mononuclear cell cytokine response.

BACKGROUND: The atopic march refers to the coexpression and progression of atopic diseases in childhood, often beginning with atopic dermatitis (AD), although children may not progress through each atopic disease. OBJECTIVE: We hypothesized that future atopic disease expression is modified by AD phenotype and that these differences result from underlying dysregulation of cytokine signaling. METHODS: Children (n = 285) were enrolled into the Childhood Origins of Asthma (COAST) birth cohort and followed prospectively. Rates of AD, food allergy, allergic rhinitis, and asthma were assessed longitudinally from birth to 18 years of age. Associations between AD phenotype and food allergy, allergic rhinitis, asthma, allergic sensitization, exhaled nitric oxide, and lung function were determined. Peripheral blood mononuclear cell responses (IL-5, IL-10, IL-13, IFN-γ) to dust mite, phytohemagglutinin, Staphylococcus aureus Cowan I, and tetanus toxoid were compared among AD phenotypes. RESULTS: AD at year 1 was associated with an increased risk of food allergy (P = .004). Both persistent and late-onset AD were associated with an increased risk of asthma (P < .001), rhinitis (P < .001), elevated total IgE (P < .001), percentage of aeroallergens with detectable IgE (P < .001), and elevated exhaled nitric oxide (P = .002). Longitudinal analyses did not reveal consistent differences in peripheral blood mononuclear cell responses among dermatitis phenotypes. CONCLUSION: AD phenotype is associated with differential expression of other atopic diseases. Our findings suggest that peripheral blood cytokine dysregulation is not a mechanism underlying this process, and immune dysregulation may be mediated at mucosal surfaces or in secondary lymphoid organs.

Does having siblings really protect against childhood atopic diseases? A total population and within-family analysis.

The association between having older siblings and decreased risk for atopic symptoms is well-established. This has been interpreted as evidence for the microbiota hypothesis, i.e. that increased early-childhood microbial exposure caused by siblings protects from immune hypersensitivities. However, possible confounders of the association have received little attention. We used register data on Finnish cohorts born in 1995-2004 (N = 559,077) to assess medication purchases for atopic diseases: antihistamines, eczema medication, asthma medication and Epinephrine. We modelled the probability of atopic medication purchases at ages 0-15 by birth order controlling for important observed confounders and all unobserved genetic and environmental characteristics shared by siblings in a within-family fixed effects model. We further studied medication purchases among first-borns according to the age difference with younger siblings to assess whether having younger siblings in early childhood is beneficial. Having older siblings was associated with a lower probability of atopic medication purchases. Compared to first-borns, the probability was 10-20% lower among second-borns, 20-40% lower among third-borns, and 30-70% lower among subsequent children, depending on medication type. Confounding accounted for up to 75% of these differences, particularly for asthma and eczema medication, but significant differences by birth order remained across all medication types. Among first-borns, a smaller age difference with younger siblings was related to a lower likelihood of atopic medication use. Our results, based on designs that account for unobserved confounding, show that exposure to siblings in early childhood, protects from atopic diseases, and thus strongly support the microbiota hypothesis.

Outcomes of endoscopic sinus surgery in patients with central compartment atopic disease.

Background: Central compartment atopic disease (CCAD) is a subtype of chronic rhinosinusitis (CRS). Research focusing on the endoscopic sinus surgery (ESS) outcomes of CCAD is limited. This study aimed to evaluate the outcomes of ESS in CCAD and compared to 2 following subtypes: chronic rhinosinusitis with nasal polyps (CRSwNP) and concomitant polypoid disease in the central compartment (CRSwNP/CC) and CRSwNP not otherwise specified (CRSwNP NOS). Methods: This case-control study enrolled patients with bilateral CRSwNP who underwent ESS and had at least 1 year of follow-up. Patients were classified into CCAD, CRSwNP/CC, and CRSwNP NOS. The demographic data, preoperative disease severity, and surgery outcomes, including CRS control status, endoscopic score, and symptom scores at 1 year postoperatively, were collected. We defined well controlled and partly controlled as appropriate disease control. Results: This study screened 259 patients and enrolled 138 patients with complete medical records and 1-year follow-up (CCAD N = 51, CRSwNP/CC N = 55, CRSwNP NOS N = 32). Among them, appropriate disease control was achieved in 84.3% of patients (43/51) in the CCAD group, 69.1% (38/55) in the CRSwNP/CC group, and 93.7% (30/32) in the CRSwNP NOS group (P = 0.029). Then we performed post-hoc analysis using appropriate disease control and uncontrolled. There was a significant difference between CRSwNP/CC and CRSwNP NOS (P = 0.007), but no significant difference compared CCAD group to CRSwNP/CC group (P = 0.065) and CRSwNP NOS group (P = 0.199). There were significant differences in endoscopic E-score among groups (P < 0.001). In post-hoc analysis, we found that CRSwNP/CC (Median [IQR], 33.32 [42.14]) had a significantly worse E-score than CCAD (8.33 [16.67]) and CRSwNP NOS (4.17 [8.30]). Also, postoperative olfactory visual analog scale (VAS) scores significantly differed among groups (P = 0.043). However, post-hoc analysis showed no difference between any 2 groups. There were no differences in postoperative VAS scores of obstruction (P = 0.159), rhinorrhea (P = 0.398), and headache/facial pain (P = 0.092). Conclusion: Most CCAD patients had good surgical outcomes 1 year after surgery. Meanwhile, the CRSwNP/CC group had the fewest patients under appropriate disease control.

Reported food-related symptoms and food allergen sensitization in a selected adult population in Hyderabad, India: A hospital-based survey.

Background: Research on reported food-related triggers of atopic disease in South Asian adults is lacking despite the region's large population and the global significance of allergic diseases. Objectives: The study aimed to identify prevalent local food items and assess allergic sensitization rates to potential trigger foods for atopic diseases via skin prick and specific IgE testing. Methods: The study began with a pilot survey of 100 subjects recruited from 4 hospitals in Hyderabad, India, focusing on foods perceived to relate to asthma, allergic rhinitis, atopic dermatitis, urticaria, and gastrointestinal allergic symptoms. A subsequent main study evaluated 2010 participants, 1754 of whom were diagnosed with an aforementioned atopic disease and who reported allergic symptoms related to any of 77 foods identified in the pilot study. Ultimately 1622 patients who consented to skin prick and specific IgE testing and who reported at least 1 food item triggering allergic diseases were included in the final analysis. Results: Among 1622 patients (average age, 42.6 ± 12.9 years; 55.5% male), asthma was the most commonly diagnosed atopic disease (26.4%), with itching and rash being frequently reported symptoms (22.7%). Notably, 94.9% of patients had total serum IgE > 144 kU/L. Chickpea, cabbage, eggplant, walnut, cumin, and betel leaf were the most commonly reported trigger foods. Conclusion: In this sample of South Indian adults diagnosed with allergic disease, reported food triggers were most commonly local dietary staples, while reported reactions to priority allergens like peanut and sesame were conspicuously absent. Observed concordance between patient-reported food triggers and sensitization to reported food triggers was low, highlighting the need for improved clinical evaluation of suspected triggers.

Association between atopic disease and vaccination granulomas: A nested case-control study.

BACKGROUND: Vaccination granulomas are observed in 1% of all children vaccinated with an aluminium-adsorbed vaccine. Most children with granulomas also have aluminium contact allergy (CA). CA and atopic diseases are both highly prevalent among children and may be associated. OBJECTIVE: To investigate the association between vaccination granulomas and atopic dermatitis (AD), asthma and rhinitis in children. METHODS: We sourced a cohort of all Danish children born from 2009 to 2017 and conducted a nested case-control study, with cases defined as children with vaccination granulomas, matched to controls 1:10 on sex, socioeconomic class, gestational age and season of birth. All cases and controls were vaccinated with aluminium-adsorbed vaccines and followed until their second birthday. We used conditional logistic regression to estimate the odds ratios (ORs). RESULTS: The study included 2171 cases with vaccination granulomas, and 21 710 controls. Children with a diagnosis of AD had a significantly higher risk of a vaccination granuloma (OR 1.50, 95% confidence intervals [CI] 1.25-1.80). No significant association was found between granulomas and asthma or rhinitis. The association between granulomas and AD was even higher in an additional sensitivity-analysis, following the children until their fourth birthday (OR 2.71, 95% CI 2.36-3.11). CONCLUSION: AD was significantly associated with vaccination granulomas, but not with other atopic diseases, within both the first 2 and 4 years of life.

Bacteriology of Different Phenotypes of Chronic Rhinosinusitis.

OBJECTIVES: Chronic rhinosinusitis (CRS) reduces the health-related quality of life and subsequently causes a tremendous socio-economic impact. Although many studies have been conducted, few have identified a relationship between bacteriological characteristics and different phenotypes or endotypes. Therefore, this study aimed to elucidate the recent trends in bacterial cultures from different types of CRS in the Asian population. METHODS: This retrospective case-control study recruited patients diagnosed with CRS who underwent functional endoscopic sinus surgery (FESS) at a tertiary hospital in Taiwan. The patients were classified into those with chronic rhinosinusitis with nasal polyps (CRSwNP)/chronic rhinosinusitis without nasal polyps (CRSsNP), eosinophilic chronic rhinosinusitis (eCRS)/non-eosinophilic chronic rhinosinusitis (NECRS), and central compartment atopic disease (CCAD)/lateral-dominant nasal polyp (LDNP) groups. The demographic data and bacteriological characteristics of the groups were analyzed. RESULTS: We included 503 patients, identifying no significant difference between CRSwNP and CRSsNP for several common bacteria in CRS. The number of Staphylococcus epidermidis isolates in culture was significantly higher in the NECRS group (50.46% vs. 32.56%, p = 0.0003) than that in the eCRS group. The number of methicillin-resistant Staphylococcus aureus (MRSA; 8.51% vs. 2.35%, p = 0.0221) positive isolates was significantly higher in the CCAD group than that in the LDNP group. CONCLUSIONS: This was the first study in Asia to analyze the relationship between bacteriological characteristics and CCAD. MRSA is significantly higher in the CCAD group than that in the LDNP group. Recognizing the unique microbiology of CRSwNP, eCRS, and CCAD is crucial when selecting antimicrobial therapy to lessen the socio-economic impact. LEVEL OF EVIDENCE: 3 Laryngoscope, 134:1071-1076, 2024.

Allergy and Asthma Prevalence and Management Across Nasal Polyp Subtypes.

Allergy and asthma prevalence vary across different subsets of chronic rhinosinusitis with nasal polyposis. In this article, the authors investigate the management of allergy and asthma within populations of patients with aspirin-exacerbated respiratory disease, allergic fungal rhinosinusitis, and central compartment atopic disease. Topical steroids, nasal rinses, and endoscopic sinus surgery are frequently employed in the management of nasal polyposis. Further, other causes of upper and lower airway inflammation like allergy and asthma should be considered in the overall treatment plan in order to optimize outcomes.

A Cross-Sectional Analysis to Assess the Role of Atopy in Keratoconus Among Saudi Population.

Background: In cases of atopy, IgE antibodies are formed in reaction to certain environmental factors like house dust mites, pollen, or even food allergens. Some studies have shown an association between atopic diseases and keratoconus. This study aims to determine the prevalence of atopy and its associated factors among keratoconus patients. Materials and Methods: A cross-sectional study was conducted among the Jazan population attending ophthalmology clinics regardless of their sex. Data collection started in August 2020 and finished in mid-June 2021. The sample was selected using the convenience sampling technique, and the total sample size was 83 participants. Data were collected via a questionnaire-based interview that contained 46 questions in the Arabic language. The data collected were analyzed using SPSS software. Results: Family history is the leading predisposing factor for keratoconus (P < 0.001). Also, eye rubbing was a significant (P < 0.015) trigger for keratoconus. However, other factors, including demographic factors such as gender and atopic conditions, did not have any significant association. Conclusion: A combination of genetic and environmental factors is the leading cause of the development of keratoconus; however, family history is the most influential factor, followed by eye rubbing.

Limited clinical role of blood eosinophil levels in early life atopic disease: A mother-child cohort study.

BACKGROUND: Blood eosinophil count is a well-established biomarker of atopic diseases in older children and adults. However, its predictive role for atopic diseases in preschool children is not well established. OBJECTIVE: To investigate the association between blood eosinophil count in children and development of atopic diseases up to age 6 years. METHODS: We investigated blood eosinophil count at age 18 months and 6 years in relation to recurrent wheeze/asthma, atopic dermatitis, allergic rhinitis, and allergic sensitization during the first 6 years of life in the two Copenhagen Prospective Studies on Asthma in Childhood cohorts (n = 1111). Blood eosinophil count was investigated in association with remission of existing atopic disease, current atopic disease, and later development of atopic disease. RESULTS: Blood eosinophil count at 18 months was not associated with current wheezing/asthma or atopic dermatitis, while blood eosinophil count at age 6 years was associated with increased occurrence of current wheezing/asthma (OR = 1.1; 1.04-1.16, p = .0005), atopic dermatitis (OR = 1.06; 1.01-1.1, p = .02), and allergic rhinitis (OR = 1.11; 1.05-1.18, p = .0002). Blood eosinophil count at 18 months did not predict persistence or development of recurrent wheeze/asthma or atopic dermatitis at age 6 years. CONCLUSION: Blood eosinophil count at 18 months was not associated with current wheezing/asthma or atopic dermatitis and did not predict persistence or development of disease. This implies a limited clinical role of blood eosinophil levels in early-life atopic disease and questions the clinical value of blood eosinophil counts measured in toddlers as a predictive biomarker for subsequent atopic disease in early childhood.