Current Pediatric Reviews - Volume 16, Issue 2, 2020

Eosinophilia is not a rare finding in clinical practice, and often poses problems in terms of etiologic research and differential diagnosis. Peripheral eosinophilia is defined by a blood eosinophil count > 500 cells/μL. It is classified into mild (500-1500 cells/μl), moderate (1500-5000 cells/μl) and severe for an eosinophil count > 5000 cells /μl. The term "hypereosinophilia” defines a condition characterized by a blood eosinophil count >1500 cells/μl in at least two consecutive tests made with a minimum of a 4-week interval. The causes of eosinophilia are various, and can be summarized by the acronym “APLV” which refers to Allergic disorders, Parasitic infections, Leukemia/ Lymphomas (and solid tumors) and Vasculitis-Immunodeficiency diseases, with allergic disorders and parasitic infections representing the most commonly identified causes. Allergic disorders are usually associated with mild eosinophilia, whereas values >20.000 cell/μl are highly suggestive for myeloproliferative disorders. Eosinophils may also be directly responsible for organ damage, mainly at cardiac, pulmonary and cutaneous level, deriving from the release of the granule products, of lipidic mediators and cytokines. Therefore, in the physician’s approach to a patient with persistent hypereosinophilia, it is also important to investigate the presence of organ involvement. In this review, we propose a diagnostic algorithm for children presenting with either blood eosinophilia or hypereosinophilia. This algorithm focuses on the patient’s history and clinical manifestations as the first step and the level and persistence of blood eosinophilia as the second, and this can help the physician to identify patients presenting with an elevated blood eosinophil count that need further laboratory or instrumental investigations.

The recent and extensive study of the microbiome has provided an enormous amount of data concerning the type and possible functions of microorganisms present in the gut, airways, genital tract, and skin. These data showed interpersonal differences in the composition of the microbiome and these differences suggest a link between the microbiome, the immune modulation, and the pathogenesis of allergic diseases. This research is particularly relevant in paediatrics, since allergic diseases are constantly increasing and there is evidence in the paediatric age that shows that the composition of the microbiome in the foetal and neonatal period plays a key role in the development of the immune system: vaginal delivery, breastfeeding, childhood spent in rural environments and/or in contact with animals result in a greater biodiversity of the microbiome with the presence of protective species that reduce the activation of Th2 lymphocytes, involved in allergic reactions. Further studies are necessary to better understand the microbiota role in the pathogenesis of atopy in order to understand if specific probiotics and prebiotics, administered orally or topically, can affect the microbiota composition and modulate immune system functions, producing a therapeutic effect in the treatment of allergic diseases. This narrative review analysed the available literature regarding the correlation between the microbiome and the development of allergic diseases and with special focus on paediatric studies. The skin, gut or lung dysbiosis can be a cofactor in the pathogenesis of allergies and the remodulation of the microbiome becomes an important therapeutic challenge.

Food allergies, defined as an immune response to food proteins, affect as many as 8% of young children and 2% of adults in western countries, and their prevalence appears to be rising like all allergic diseases. In addition to well-recognized urticaria and anaphylaxis triggered by IgE antibody– mediated immune responses, there is an increasing recognition of cell-mediated disorders, such as eosinophilic esophagitis and food protein–induced enterocolitis. Non-IgE-Mediated gastrointestinal food allergies are a heterogeneous group of food allergies in which there is an immune reaction against food but the primary pathogenesis is not a production of IgE and activation of mast cells and basophils. Those diseases tend to affect mainly the gastrointestinal tract and can present as acute (FPIES) or chronic reaction, such as Eosinophilic Esophagitis (EoE), Food Protein-Induced Allergic Proctocolitis (FPIAP). The role of food allergy in Non-EoE gastrointestinal Eosinophilic disorders (Non- EoE EGID) is poorly understood. In some diseases like EoE, T cell seems to play a major role in initiating the immunological reaction against food, however, in FPIES and FPIAP, the mechanism of sensitization is not clear. Diagnosis requires food challenges and/or endoscopies in most of the patients, as there are no validated biomarkers that can be used for monitoring or diagnosis of Non-IgE mediated food allergies. The treatment of Non-IgE food allergy is dependent on diet (FPIES, and EoE) and/or use of drugs (i.e. steroids, PPI) in EoE and Non-EoE EGID. Non-IgE mediated food allergies are being being investigated.

Primary eosinophilic gastrointestinal diseases (EGIDs) represent a heterogeneous group of disorders characterized by eosinophilic inflammation in the absence of known causes for eosinophilia, selectively affecting different segments of the gastrointestinal tract. While pediatric eosinophilic esophagitis (EoE) is a well-defined disease with established guidelines, Eosinophilic Gastritis (EoG), Eosinophilic Gastroenteritis (EoGE) and Eosinophilic Colitis (EoC) remain a clinical enigma with evidence based on limited anecdotal case reports. Large cross-sectional studies in the US defined a prevalence of EoG and EoGE ranging from 1,5 to 6,4/100.000 and from 2,7 to 8,3/100.000 subjects respectively, while the prevalence of EoC ranges from 1,7 to 3,5/100.000 subjects. Regarding the pathogenesis, it is hypothesized that EGIDs result from the interplay between genetic predisposition, intestinal dysbiosis and environmental triggers. Clinically, EGIDs might present with different and nonspecific gastrointestinal symptoms depending on the involved intestinal tract and the extension of eosinophilic inflammatory infiltrate. The diagnosis of EGIDs requires: 1. recurrent gastrointestinal symptoms, 2. increased eosinophils for high power field in biopsy specimens, 3. absence of secondary causes of gastrointestinal eosinophilia. No validated guidelines are available on the clinical management of patients with EGIDs. Evidence from case reports and small uncontrolled case series suggests the use of dietary and corticosteroids as the first-line treatments. Considering the clinical follow-up of EGIDs, three different patterns of disease course are identified: single flare, recurring course-disease and chronic course-disease. This review will focus on pediatric EGIDs distal to esophagus, including Eosinophilic Gastritis (EoG), Eosinophilic Gastroenteritis (EoGE) and Eosinophilic Colitis (EoC).

Consistent evidence has been found on the relationship between food allergy (FA) and atopic dermatitis (AD) in some children. Food sensitization can be often found in these patients. Allergy should be confirmed, though, with a food challenge test (FC) before advising a restrictive diet which could be harmful for the patient. Younger children with AD frequently show sensitization to egg, milk or peanut, while older ones and adults are more often sensitized to environmental allergens such as house dust mites, moulds, animal dander or pollens. It is well known that a barrier disturbance plays a main role in the development of sensitization and allergy. Therefore, due to the early appearance of AD, preventive newborn skincare with emollients and early introduction of food appear to be very important to determine food tolerance.

Food allergy is a potentially life-threatening medical condition and a significant public health concern worldwide. The current management consists of strict avoidance of the culprit food and treating any adverse reactions from unintended food ingestion. The increasing prevalence of food allergy encouraged research and clinical trials in the field of specific allergen immunotherapy (AIT) which represents an appealing approach, especially in pediatric age. AIT consists of the gradual administration of growing amounts of the offending allergen in order to induce food desensitization, which is an increase in the threshold for reactivity while continuing on regular exposure to the allergen. AIT can be administered through oral, sublingual, epicutaneous, and subcutaneous routes. Reports on oral immunotherapy (OIT) thus far have been more extensive. The desirable goal is to achieve "post desensitization effectiveness", that is the ability to introduce food without reaction even after a period of discontinuation of the offending food. Other therapeutic approaches are being studied alongside immunotherapy such as modified proteins, probiotics, Chinese herbal supplements, biologic therapies, and DNA vaccines.

Allergen-specific immunotherapy (AIT) for aeroallergens consists of the administration of standardized allergen extracts to patients with respiratory IgE-mediated diseases to the same allergen in order to achieve immune tolerance to the allergen and prevent the onset of symptoms. AIT is usually delivered by sublingual (SLIT), subcutaneous (SCIT) route. AIT with one or multiple allergens currently represents the only causal treatment able to change the natural history of allergic airway diseases. Significant progresses have been made in terms of AIT efficacy and safety. In this paper, mechanisms of action, indication and side effects of allergen immunotherapy are reviewed. SLIT and SCIT have been found to be effective in the treatment of asthma and rhinoconjunctivitis due to inhalant allergens. The route of AIT administration should be selected on availability, cost (dependent from the local health system), tolerability (better for SLIT), patient’s preference (injections are less accepted in young children), and adherence (higher for SCIT beyond pediatric age). However, it should be taken into account that metanalyses on AIT do not consider that effectiveness and safety depend upon the product chosen for treatment. Each product should be separately assessed to avoid generalization on administration routes or age group that may affect the decision.

The prevalence of allergic diseases has been remarkably increased in the last decades. The global health burden of these conditions is substantial, since patients may experience disability, anxiety and emotional distress, social restrictions, and reduced quality of life and productivity, in particular, in the most severe cases. Recent advances in understanding the pathophysiology of allergic disorders have allowed identifying novel therapeutic strategies for the treatment of severe and uncontrolled allergic diseases. Although most studies have been performed in allergic asthma, biological drugs targeting other allergic diseases such as chronic spontaneous urticaria, atopic dermatitis, and food allergy are showing promising results. In this review, the most recent evidence on biologic therapies for allergic diseases, focusing on the pediatric age has been presented.

Infants born prematurely (before completion of 37 weeks of gestation) are at increased risk of morbidity and mortality due to vaccine preventable diseases, mostly because of their immunological immaturity and failure of transfer of maternal protective antibodies. Despite their great need of being vaccinated, concerns on vaccine safety and efficacy, constitute the main reasons for which vaccinations are often delayed in this group. In this review we summarize the latest evidence on vaccine safety, efficacy and immunogenicity in preterm infants which is similar to full-term infants. Therefore there is no reason for delaying vaccination in this population.

Noise may cause stress responses such as apnea, hypoxemia, changes in oxygen saturation and augmented oxygen consumption secondary to elevated heart and respiratory rates. Moreover, stress results in increased intracranial pressure, abnormal sleep patterns, hearing impairment, and bronchopulmonary dysplasia, retinopathy of prematurity, intraventricular hemorrhage, periventricular leukomalacia, retardate development and alterations in the neuroendocrine system. Herein, this study aimed to discuss the effects of earmuffs on physiological parameters in preterm infants. The relevant and available peer-reviewed publications from 2012 to 2018 from various databases were analyzed. For the assessment of the studies, the full-text accessible studies were included for analysis. The retrieved documents were analyzed using VOSviewer regarding the geographical distributions of the documents with their numbers and citations, keywords proposed by the researchers. All records with the term “earmuffs OR earmuff” in the “article title, abstract, keywords” were retrieved from different databases. Accordingly, 396 documents containing the word “earmuffs OR earmuff” were recorded. The search was then restricted for publications that contain the words “noise AND nursing AND preterm” in the title and abstracts (TITLE-ABS-KEY (earmuffs OR earmuff)) AND (noise AND nursing AND preterm) (Scopus=390; Web of Science=1, Medline=2; Cochrane=1; Embase=1= Pubmed=1=n=396). After inclusion and exclusion criteria, 7 documents were recorded and then evaluated for the present study. As a conclusion, the effects of earmuffs on physiological parameters of preterm infants have not been clearly understood and reported yet. Along with the present documents, it is not clear that the use of earmuffs reduces stress and provides physiological stability in preterm infants born between approximately 28-32 weeks. The studies with a larger sample size are needed for validation of information reported in the articles analyzed herein.