The role of the atopy patch test in the diagnostic work-up of non-IgE gastrointestinal food allergy in children: a systematic review.

The "Atopy Patch Test" (APT) has been proposed as a diagnostic tool for food allergies (FA), especially in children with FA-related gastrointestinal symptoms. However, its diagnostic accuracy is debated, and its usefulness is controversial. The aim of this systematic review was to evaluate the APT diagnostic accuracy compared with the diagnostic gold standard, i.e., the oral food challenge (OFC), in children affected by non-IgE mediated gastrointestinal food allergies, including the evaluation in milk allergic subgroup. Both classical non-IgE mediated clinical pictures and food induced motility disorders (FPIMD) were considered. The search was conducted in PubMed and Scopus from January 2000 to June 2022 by two independent researchers. The patient, intervention, comparators, outcome, and study design approach (PICOS) format was used for developing key questions, to address the APT diagnostic accuracy compared with the oral food challenge (OFC). The quality of the studies was assessed by the QUADAS-2 system. The meta-analysis was performed to calculate the pooled sensitivity, specificity, DOR (diagnostic odds ratio), PLR (positive likelihood ratio), and NLR (negative likelihood ratio) with their 95% confidence intervals (CI). Out of the 457 citations initially identified via the search (196 on PubMed and 261 on Scopus), 37 advanced to full-text screening, and 16 studies were identified to be included in the systematic review. Reference lists from relevant retrievals were searched, and one additional article was added. Finally, 17 studies were included in the systematic review. The analysis showed that APT has a high specificity of 94% (95%CI: 0.88-0.97) in the group of patients affected by FPIMD. Data showed a high pooled specificity of 96% (95% CI: 0.89-0.98) and the highest accuracy of APT in patients affected by cow's milk allergy (AUC = 0.93).      Conclusion: APT is effective in identifying causative food in children with food-induced motility disorders.  What is Known: • Atopy patch test could be a useful diagnostic test for diagnosing food allergy, especially in children with food allergy-related gastrointestinal symptoms. What is New: • Atopy patch test may be a useful tool in diagnosing non IgE food allergy, especially in children with food-induced gastrointestinal motility disorders and cow's milk allergy.

Mometasone furoate nasal spray in Italian children with seasonal allergic rhinitis: a comprehensive assessment.

OBJECTIVE: Seasonal allergic rhinitis (SAR) is a common disease of childhood and is characterized by type 2 inflammation, bothersome symptoms, and impaired quality of life (QoL). Intranasal corticosteroids are effective medications in managing SAR. In addition, mometasone furoate nasal spray (MFNS) is a well-known therapeutic option. However, the literature provided no data about the effects of MFNS in European children with SAR. Thus, this study addressed this unmet requirement. METHODS: MFNS was compared to isotonic saline. Both treatments were prescribed: one drop of spray per nostril, twice a day, for 3 weeks. Nasal cytology, total symptom score (TSS), visual analogic scale concerning the parental perception of severity of symptoms, and the Pediatric Rhinoconjunctivitis Quality of Life Questionnaire (PRQLQ) were assessed at baseline, after 7 and 21 days, and 1 month after discontinuation. RESULTS: MFNS significantly reduced eosinophil and mast cell counts, improved QoL, and relieved symptoms, as assessed by doctors and perceived by parents. These effects persisted over time, even after discontinuation. Both treatments were safe and well-tolerated. CONCLUSIONS: The present study documented that a 3-week MFNS treatment was able to significantly dampen type 2 inflammation, improve QoL, and reduce severity of symptoms in Italian children with SAR, and was safe.

Summation anaphylaxis: A challenging diagnosis.

Anaphylaxis is the most severe of allergic reactions. The most frequent triggers of anaphylaxis in childhood are food, insect venom, drugs, exercise, etc. In some cases, the presence of more than one trigger is necessary for the allergic reaction, while one trigger alone is tolerated. This rare condition is called summation anaphylaxis (SA). Food-dependent exercise-induced anaphylaxis is the most well-known SA. However, SA may also occur with the association between food and/or exercise plus one or more of the following other cofactors, such as drugs, especially non-steroidal anti-inflammatory (NSAID), alcohol, infections, temperature variation, and menstrual cycle. SA can explain some cases of idiopathic anaphylaxis, as well as cases of an apparent breakdown in a previously acquired tolerance for food, or finally, when faced with a suggestive clinical history of food allergy or exercise anaphylaxis and the provocation test is negative. In these situations, a more careful clinical history looking for other cofactors is necessary.

Treatment of Severe Asthma: Case Report of Fast Action of Mepolizumab in a Patient with Recent SARS-CoV-2 Infection.

Asthma is one of the most common chronic inflammatory diseases of childhood with a heterogeneous impact on health and quality of life. Mepolizumab is an antagonist of interleukin-5, indicated as an adjunct therapy for severe refractory eosinophilic asthma in adolescents and children aged >6 years old. We present the case of a 9 year-old boy with severe asthma who experienced several asthmatic exacerbations following a SARS-CoV-2 infection, necessitating therapy with short-acting bronchodilators, oral corticosteroids, and hospitalization. We follow the patient using validated questionnaires for the evaluation of asthma control: Children Asthma Control Test, Asthma Control Questionnaire, respiratory function tests, and evaluation of exhaled nitric oxide fraction. After 12 weeks from the start of therapy with mepolizumab, we found significant improvements in lung function, a reduction in the degree of bronchial inflammation, and improvements in quality of life. No asthmatic exacerbations have been reported since the initiation of treatment with mepolizumab. Respiratory infections, such as those related to SARS-CoV-2, represent a significant risk factor for exacerbations in patients with moderate to severe forms of asthma. In our experience, following new episodes of exacerbation, the initiation of treatment with mepolizumab has allowed us to improve asthma control and enhance the quality of life of patients from the first doses. Although mepolizumab showed promise in this child with severe asthma during SARS-CoV-2 infection, the results from this single case cannot be generalized. Further studies are needed to confirm its safety and effectiveness.

Mini-Review on Vitamin D in Pediatric Population and its Role in Respiratory and Atopic Disorders.

In recent years, our comprehension of the function of vitamin D has significantly evolved. The ubiquitous presence of the vitamin D receptor (Vitamin D Receptor- VDR) in the body has led to its redefinition from a steroidal hormone primarily involved in skeletal functions to a hormone with pleiotropic effects, exerting its influence on the circulatory, nervous, and immune systems. This has prompted investigations into its potential use in preventing and treating chronic metabolic disorders, cardiovascular diseases, infections, and allergic and autoimmune diseases. This comprehensive review explores the various aspects of vitamin D, including its sources, synthesis, functions, and its impact on different physiological systems. It delves into the epidemiology of vitamin D deficiency, highlighting its occurrence among various age demographics and geographic regions. The impact of vitamin D on the immune system is also explored, elucidating its immunomodulatory and anti-inflammatory properties, particularly in the context of respiratory infections. The review discusses emerging evidence concerning the potential advantages of vitamin D in respiratory diseases, pediatric asthma and atopic dermatitis. It also addresses vitamin D supplementation recommendations for various pediatric populations, including term and preterm infants. The growing concern regarding the global health impacts of insufficient vitamin D levels necessitates further research to bridge gaps in knowledge, particularly in enhancing screening, prevention, and approaches to address vitamin D deficiency from birth onwards. In summary, this comprehensive overview underscores the vital role of vitamin D, highlighting the significance of understanding its multifaceted functions and the need for tailored supplementation strategies, especially in vulnerable populations.

Exploring the Interplay between Asthma and Hemoglobinopathies: A Comprehensive Review.

Asthma, a prevalent chronic respiratory condition characterized by inflammation of the airways and bronchoconstriction, has demonstrated a potential association with hemoglobinopathies such as thalassemia and sickle cell disease (SCD). Numerous studies have highlighted a higher prevalence of asthma among thalassemia patients compared to the general population, with rates ranging around 30%. Similarly, asthma frequently coexists with SCD, affecting approximately 20-48% of patients. Children with SCD often experience heightened lower airway obstruction and airway hyper-reactivity. Notably, the presence of asthma in SCD exacerbates respiratory symptoms and increases the risk of severe complications like acute chest syndrome, stroke, vaso-occlusive episodes, and early mortality. Several studies have noted a decrease in various cytokines such as IFN-γ and IL-10, along with higher levels of both IL-6 and IL-8, suggesting an overactivation of pro-inflammatory mechanisms in patients with hemoglobinopathies, which could trigger inflammatory conditions such as asthma. The exact mechanisms driving this association are better elucidated but may involve factors such as chronic inflammation, oxidative stress, and immune dysregulation associated with thalassemia-related complications like chronic hemolytic anemia and iron overload. This review aims to comprehensively analyze the relationship between asthma and hemoglobinopathies, with a focus on thalassemia and SCD. It emphasizes the importance of interdisciplinary collaboration among pulmonologists, hematologists, and other healthcare professionals to effectively manage this complex interplay. Understanding this link is crucial for improving care and outcomes in affected individuals.

Transplant-Acquired Food Allergy in Children.

BACKGROUND: Organ transplantation in children is a vital procedure for those with end-stage organ failure, but it has been linked to the development of post-transplant allergies, especially food allergies. This phenomenon, known as transplant-acquired food allergy (TAFA), is becoming increasingly recognized, though its mechanisms remain under investigation. Pediatric transplant recipients often require lifelong immunosuppressive therapy to prevent graft rejection, which can alter immune function and heighten the risk of allergic reactions. Our review aimed to gather the latest evidence on TAFA. METHODS: We conducted a PubMed search from 25 June to 5 July 2024, using specific search terms, identifying 143 articles. After screening, 36 studies were included: 24 retrospective studies, 1 prospective study, 2 cross-sectional researches, and 9 case reports/series. RESULTS: Most studies focused on liver transplants in children. The prevalence of food allergies ranged from 3.3% to 54.3%. Tacrolimus, alongside corticosteroids, was the most commonly used immunosuppressive therapy. In addition to food allergies, some patients developed atopic dermatitis, asthma, and rhinitis. Allergic symptoms typically emerged within a year post-transplant, with common allergens including milk, eggs, fish, nuts, soy, wheat, and shellfish. Both IgE-mediated and non-IgE-mediated reactions were observed, with treatment often involving the removal of offending foods and the use of adrenaline when necessary. CONCLUSIONS: Consistent immunological monitoring, such as skin prick tests and IgE level assessments, is essential for early detection and management of allergies in these patients. Understanding the link between transplantation and allergy development is crucial for improving long-term outcomes for pediatric transplant recipients.

COVID-19 Pediatric Follow-Up: Respiratory Long COVID-Associated Comorbidities and Lung Ultrasound Alterations in a Cohort of Italian Children.

In children, the factors that influence COVID-19 disease and its medium- and long-term effects are little known. Our investigation sought to evaluate the presence of comorbidity factors associated with respiratory long COVID manifestations in children and to study ultrasound abnormalities following SARS-CoV-2 infection. Children, who arrived at the 'Respiratory Diseases of Pediatric Interest Unit' at the Department of Woman, Child, and General and Specialized Surgery of the University of Campania 'Luigi Vanvitelli', were selected during the timeframe from September 2021 to October 2022. The children were diagnosed with a SARS-CoV-2 infection that occurred at least one month before the visit. All patients followed a COVID-19 follow-up protocol, developed by the Italian Society of Pediatric Respiratory Diseases (SIMRI), which included: collection of data regarding SARS-CoV-2 illness and history of known respiratory and allergic diseases; physical examination; BMI assessment; baseline spirometry and after bronchodilation test; six-minute walking test; and lung ultrasound (LUS). In a cohort of 104 participants with respiratory long COVID symptoms (64.7% male, average age 8.92 years), 46.1% had fever with other symptoms, and 1% required hospitalization. BMI analysis showed 58.4% of the cohort was overweight. The LUS was positive in 27.0% of cases. A significant BMI association was observed with COVID-19 symptoms and LUS score (p-value < 0.05). No associations were found with asthma or atopy.

Anaphylaxis after Shrimp Intake in a European Pediatric Population: Role of Molecular Diagnostics and Implications for Novel Foods.

(1) Background: Tropomyosin is a major cause of shellfish allergy and anaphylaxis triggered by food. It acts as a pan-allergen, inducing cross-reactivity in insects, dust mites, crustaceans, and mollusks. Our study investigates anaphylaxis in children with asthma or atopic diseases after consuming tropomyosin-containing food. (2) Methods: We analyzed the molecular sensitization profiles of pediatric patients at the University of Campania 'Luigi Vanvitelli' from 2017 to 2021, with conditions such as allergic rhinitis, asthma, atopic dermatitis, urticaria, and food allergies. (3) Results: Out of a total of 253 patients aged 1 to 18 years (167 males, 86 females), 21 patients (8.3%) experienced anaphylaxis after shrimp ingestion. All 21 (100%) were sensitized to various tropomyosins: Pen m 1 (100%), Der p 10 (90.5%), Ani s 3 (81%), and Bla g 7 (76.2%). Clinical symptoms included allergic asthma (76.2%), atopic dermatitis (61.9%), urticaria (38.1%), and allergic rhinitis (38.1%). (4) Conclusions: Crustaceans and mollusks are major allergens in Italy and Europe, requiring mandatory declaration on food labels. Italian pediatric patients demonstrated significant anaphylaxis after consuming shrimp, often accompanied by multiple atopic disorders such as asthma, rhinitis, and atopic dermatitis. Considering the cross-reactivity of tropomyosin among various invertebrates and the emergence of 'novel foods' containing insect flours in Europe, there is ongoing debate about introducing precautionary labeling for these products.

Sensitization to nsLTP: A Retrospective Study in An Italian Pediatric Population over the Last Decade.

Background: Food allergy is common in the Mediterranean, especially concerning lipid transfer proteins (LTPs) allergy. LTPs are widespread plant food allergens in fruits, vegetables, nuts, pollen, and latex. Also, LTPs are prevalent food allergens in the Mediterranean area. They can sensitize via the gastrointestinal tract and cause a wide range of conditions: from mild reactions, such as oral allergy syndrome, to severe reactions, such as anaphylaxis. LTP allergy in the adult population is well described in the literature, concerning both the prevalence and clinical characteristics. However, there is poor knowledge about its prevalence and clinical manifestation in children living in the Mediterranean. Materials and Methods: This study, including 800 children aged from 1 to 18 years, investigated the prevalence of 8 different molecules of nonspecific LTP over time in an Italian pediatric population visited over the last 11 years. Results: About 52% of the test population was sensitized to at least one LTP molecule. For all the LTPs analyzed, sensitization increased over time. In particular, using the years 2010 through 2020 as a comparison, the major increases were observed for the LTPs of the English walnut Jug r 3, the peanut Ara h 9, and the plane tree Pla a 3 (about 50%); the increase of the LTP of the Hazelnut Cor a 8 was about 36%, and that of the LTP of the artemisia Art v 3 was approximately 30%. Conclusions: The latest evidence in the literature indicates an increase in food allergy prevalence in the general population, including children. Therefore, the present survey represents an interesting perspective about the pediatric population of the Mediterranean area, exploring the trend of LTP allergy.

Evaluation of Der p 10 in a Cohort of European Children: Role of Molecular Diagnostics and Clinical Features.

Background: Allergy toward the dust mite is steadily increasing on the European continent. This sensitization may be a risk factor for developing sensitization to other mite molecules such as tropomyosin Der p 10. This molecule often correlates with food allergy and the risk of anaphylaxis after ingesting mollusks and shrimps. Materials and Methods: We analyzed the sensitization profiles by ImmunoCAP ISAC of pediatric patients from 2017 to 2021. The patients under investigation were being followed for atopic disorders such as allergic asthma and food allergies. The study aimed to analyze the prevalence of sensitization toward Der p 10 in our pediatric population and assess the related clinical symptoms and reactions after ingestion of foods containing tropomyosins. Results: This study included 253 patients; 53% were sensitized toward Der p 1 and Der p 2; 10.4% were also sensitized to Der p 10. Assessing patients sensitized to Der p 1 or Der p 2, and Der p 10, we observed that 78.6% were affected by asthma (p < 0.005) and had a history of prior anaphylaxis after ingestion of shrimp or shellfish (p < 0.0001). Conclusion: The component-resolved diagnosis gave us a deeper understanding of patients' molecular sensitization profiles. Our study showed that a fair proportion of children sensitive to Der p 1 or Der p 2 are also sensitive to Der p 10. However, many patients sensitized to all three molecules had a high risk of asthma and anaphylaxis. Therefore, the assessment of Der p 10 sensitization should be considered in atopic patients with sensitization to Der p 1 and Der p 2 to avoid encountering possible adverse reactions after ingesting foods containing tropomyosins.

Behavioral and Sleep Disorders in Children and Adolescents following COVID-19 Disease: A Case-Control Study.

INTRODUCTION: Recent studies show that neuropsychiatric disorders are the most frequent sequelae of COVID-19 in children. PURPOSE: Our work aimed to evaluate the impact of SARS-CoV-2 infection on behavior and sleep in children and adolescents. MATERIALS AND METHODS: We enrolled 107 patients aged 1.5-18 years who contracted COVID-19 between one year and one month prior to data collection, referred to the University of Campania Luigi Vanvitelli in Italy. We asked their parents to complete two standardized questionnaires for the assessment of behavior (Child Behavior CheckList (CBCL)) and sleep (Sleep Disturbance Scale for Children (SLDS)). We analysed and compared the results with a control group (pre-COVID-19 pandemic). RESULTS: In the COVID-19 group, the major results were found for sleep breathing disorders, sleep-wake transition disorders and disorders of initiating and maintaining sleep for the SDSC questionnaire, and internalizing scale, total scale and anxiety/depression for the CBCL questionnaire. The comparison of the CBCL results of the cases with the controls revealed statistically significant differences for the following items: internalizing scale, externalizing scale, somatic complaints, total score, thought problems [(p < 0.01)], anxious/depressed problems and withdrawn [(p < 0.001)]. CONCLUSIONS: COVID-19 has impacted children's and adolescents' mental health. Adolescents were the most affected patient group for internalizing problems, including anxiety and depression.

Covid-19 and spirometry in this age.

In the last year, many countries adopted a plan to contain hospital infections by Sars-Cov-2 also limiting pulmonary function tests (PFTs), exclusively to indispensable cases. All the recommendations of the major scientific societies regarding the use of PFTs, in particular spirometry, in the Covid era were formulated in the initial period of the pandemic. Currently, the new scientific knowledge about Sars-Cov-2 and the vaccination among healthcare workers, shown new insight to start doing PFTs again to help the investigation and monitoring of patients with respiratory pathology. In this article, we sum up the recommendations of major International Respiratory Societies, and we shared our experience about PFTs in a Pediatric Respiratory Disease Unit during the pandemic.

Vitamin D status can affect COVID-19 outcomes also in pediatric population.

Background: vitamin D influences the immune system and the inflammatory response. It is known that vitamin D supplementation reduces the risk of acute respiratory tract infection. In the last two years, many researchers have investigated vitamin D's role in the pathophysiology of COVID-19 disease. Results: the findings obtained from clinical trials and systematic reviews highlight that most patients with COVID-19 have decreased vitamin D levels and low levels of vitamin D increase the risk of severe disease. This evidence seems to be also confirmed in the pediatric population. Conclusions: further studies (systematic review and meta-analysis) conducted on children are needed to confirm that vitamin D affects COVID-19 outcomes and to determine the effectiveness of supplementation and the appropriate dose, duration and mode of administration.

Effect of COVID-19 Lockdown on Children's Eating Behaviours: A Longitudinal Study.

The COVID-19 pandemic has had a huge impact on children's lifestyle and eating behaviour, resulting in an increase of obesity prevalence. The CEBQ (Children's Eating Behaviour Questionnaire) is a validate questionnaire that investigates children's eating behaviour. Knowing the psychological consequences of daily routine disruption during lockdown, we evaluated the changes in eating behaviours in a paediatric cohort before and during the lockdown period through the evaluation of the Italian version of the CEBQ. We prospectively enrolled children attending the pediatric clinic of the University of Campania 'Luigi Vanvitelli'. All parents answered the parent-report version of the CEBQ before lockdown containment. During lockdown, the second survey was carried out by telephone call. The study sample included 69 children. Food responsiveness and emotional overeating subscales showed higher scores during lockdown compared to data before lockdown (p = 0.009 and p = 0.001, respectively). Conversely, desire to drink and satiety responsiveness showed lower scores at follow-up (p = 0.04 and p = 0.0001, respectively). No differences were observed for slowness in eating and enjoyment of food. Delta changes were higher in normal-weight children compared to children with obesity (p = 0.02). Our results confirm that containment measures during the COVID-19 pandemic have acted as triggers on certain eating behaviors that mostly predispose to an obesogenic manner.

An Overview on the Primary Factors That Contribute to Non-Allergic Asthma in Children.

The prevalence of non-allergic asthma in childhood is low, peaking in late adulthood. It is triggered by factors other than allergens, like cold and dry air, respiratory infections, hormonal changes, smoke and air pollution. In the literature, there are few studies that describe non-allergic asthma in pediatric age. Even though it is a less common disorder in kids, it is crucial to identify the causes in order to keep asthma under control, particularly in patients not responding to conventional treatments. In this review, we discuss non-IgE-mediated forms of asthma, collecting the latest research on etiopathogenesis and treatment.

Comparing available treatments for pollen-induced allergic rhinitis in children.

INTRODUCTION: Pollen-induced allergic rhinitis (PIAR) is a widespread disease in children, and its prevalence is rapidly evolving. In addition, it may be associated with other atopic diseases, in particular asthma. In most cases, PIAR can be treated effectively by avoiding exposure to responsible allergens and using symptomatic treatments, including intranasal/oral antihistamines or/and nasal corticosteroids, according to ARIA guidelines. In recent decades, new medicines have been studied and developed: allergen-specific immunotherapy (AIT), anti-IgE antibodies, and probiotics. In addition, nutraceuticals have also been used as add-on treatments. This review aims to discuss and compare the old and new therapeutic strategies for PIAR in children. AREAS COVERED: Allergic rhinitis is a type 2 inflammatory disease. The management of patients with PIAR entails medications, AIT, and ancillary therapies. In addition, children with PIAR and associated severe asthma may be inclusively treated with biologics. Namely, subjects with allergic comorbidities could benefit from biological agents. However, AIT presently remains the unique causal treatment for PIAR. EXPERT OPINION: New strategies may include combined treatments, mainly concerning fixed associations with antihistamines and corticosteroids, nutraceutical products, and new AIT formulations.

Nasal microbiome in chronic rhinosinusitis.

Chronic rhinosinusitis (CRS) is defined as an inflammatory disorder of the paranasal sinuses and of the nasal mucosa that lasts 12 weeks or longer. In CRS microbes contribute to the disease pathogenesis. Clinical microbiology is focused on finding single pathogens that causes the disease and the main goal is the use of antibiotics to kill bacteria. Efforts to achieve a better understanding of CRS include the study of the sinus microbiome, and to evaluate the ability of probiotics to augment homeostasis and modulate the immune response of the host mucosa. This review provides an update on the role of the microbiome in CRS. The study was conducted using two databases: PubMed and Science Direct. We searched for articles in English that matched the review topic. We first used the abstracts of articles to assess whether they met the inclusion criteria. We also reviewed the references of the selected articles and read those with titles that might be of interest. Several studies have shown that endogenous microbiome dysbiosis can impact mucosa health and disease severity. Some bacterial species presenting protective or pathogenic effect. Antimicrobial agents can create a similar disruption and impact the nasal microbiome balance. On the other hand, probiotics offers a promising avenue for developing systemic and topical therapies geared towards strategic manipulation of the biological host load, thereby augmenting immune homeostasis. A better comprehension of sinus-nasal microbiome in healthy and in CRS patients and the link with different CRS phenotype can help in developing new prognostics, diagnostics, and therapeutics strategies. Going forward, the use of probiotics can restore the native sinus ecology with significant therapeutic and preventive implications.

Exercise-Induced Bronchoconstriction in Children.

Exercise-induced bronchoconstriction (EIB) is a transient airflow obstruction, typically 5-15 min after physical activity. The pathophysiology of EIB is related to the thermal and osmotic changes of the bronchial mucosa, which cause the release of mediators and the development of bronchoconstriction in the airways. EIB in children often causes an important limitation to physical activities and sports. However, by taking appropriate precautions and through adequate pharmacological control of the condition, routine exercise is extremely safe in children. This review aims to raise awareness of EIB by proposing an update, based on the latest studies, on pathological mechanisms, diagnosis, and therapeutic approaches in children.

United airway disease.

Nose and lungs are considered as anatomic and functional unit, as they share morphological, pathophysiological and immunological basis. Allergic rhinitis and asthma often coexist in the same individual, and the treatment of one also improves the symptoms of the other (one airway, one disease). The aim of this review is to discuss the interaction between upper and lower airways, based on recent scientific evidence and, critically, analyze the important implications the new findings have for the future therapy and prevention of these common diseases.