Clinical epidemiology is defined as a method for investigating the distribution and determinants of diseases and for applying this knowledge in their prevention, and simply means application of epidemiological methods for medical research. In evidence-based medicine, randomized controlled trials (RCT) are the gold standard for assessing efficacy and safety of the intervention, while it is commonly impractical because of many limitations, such as ethical/legal problems and weak external-validity. High internal-validity of RCT permits to assess the direct efficacy of intervention without interference with bias and confounder; however, it has less generalizability or applicability to the real-life practice. Evidence-based practical guidelines are developed for patient management and decision making in real-life practice; paradoxically, the evidence of the guidelines does not come from real life, but from strict trial life. To overcome these limitations, pragmatic clinical trials for assessing the effectiveness of intervention in real-life practice or high-quality observational studies would be the best alternatives or could add more strong evidence. This article provides an overview of clinicoepidemiological research designs in the field of childhood allergic diseases and their strength/weakness.
Bias (Epidemiology) ; Child ; Decision Making ; Epidemiologic Methods ; Epidemiology ; Evidence-Based Medicine ; Humans ; Hypersensitivity ; Pragmatic Clinical Trial ; Pragmatic Clinical Trials as Topic ; Research Design*

Global guidelines strongly recommend annual influenza vaccination in people age 6 months and older, particularly in asthmatic children. There is no doubt about the benefit of influenza vaccination in asthmatic children. However, some of the vaccine's components may elicit an IgE mediated hypersensitivity or disease exacerbation, including life-threatening events, in children with allergic diseases. As a result, concerns regarding the safety of the vaccine still continue today. The influenza vaccine is grown on hens' eggs and contains a trace of egg protein. Consequently, it can provoke an allergic reaction or anaphylaxis in children with an egg allergy or exacerbation in those with asthma. Therefore, we need to know the risks and benefits of the influenza vaccine and the best strategy for safe vaccination. Although most guidelines have consistently reported the safety of influenza vaccination in children with allergic disease, and have recommended annual administration, safety concerns impede guideline-based performance in practice. The safety and efficacy of influenza vaccination for allergic children are summarized in the present review.
Anaphylaxis ; Asthma ; Child* ; Disease Progression ; Egg Hypersensitivity ; Eggs ; Humans ; Hypersensitivity ; Hypersensitivity, Immediate ; Influenza Vaccines ; Influenza, Human* ; Ovum ; Risk Assessment ; Vaccination* ; Vaccines

PURPOSE: Infantile atopic dermatitis (AD) is one of the most important risk factors for development of childhood asthma. Those with persistent wheezing with atopy had a great risk of declining lung function. Our study was designed to find out the risk factors for wheezing in infants who has AD, therefore early detection of risk factors for developing wheezing. METHODS: Three hundreds forty seven infants with AD who visited on our Pediatric Allergy Respiratory Center in Soonchunhyang University Hospital from January 2002 to December 2005 were enrolled and they were followed up till July 2006. We obtained familial allergy history and laboratory data such as serum total IgE, specific IgE and blood eosinophil count. We analyzed the factors affecting recurrent wheezing and persistent wheezing after 3 years old in children who had AD during infancy. RESULTS: One-hundred ninety-four children (55.9%) developed wheezing. Male sex (adjusted odds ratio (aOR) 1.7, 95% CI 1.1-2.7) and asthma history of parents or siblings (aOR 4.7, 95% CI 1.7-12.5) were the significant risk factors for development of wheezing. Serum total IgE (aOR 5.1 95% CI 1.1-22.5) and house dust mite sensitization (aOR 9.0, 95% CI 0.9-89.4) were significant risk factors for persistent wheezing after first three years of life. CONCLUSION: We should be alert for asthma in cases of infantile AD especially in male sex or with familial asthma history. And we propose early identification and intervention for asthma in infantile AD with increased total IgE and with house dust mite sensitization.
Asthma ; Child ; Child, Preschool ; Dermatitis, Atopic* ; Eosinophils ; Humans ; Hypersensitivity ; Immunoglobulin E ; Infant* ; Lung ; Male ; Odds Ratio ; Parents ; Pyroglyphidae ; Respiratory Center ; Respiratory Sounds* ; Risk Factors* ; Siblings

PURPOSE: Recent studies suggest that oral probiotic administration might be useful in the management of atopic dermatitis. Probiotics are known to promote the maturation of gut- associated lymphoid tissue (GALT) and control inflammatory responses. The purpose of this study was to evaluate clinical and anti-inflammatory effects on children's atopic dermatitis with Lactobacillus casei (L. casei), a kind of probiotic, supplementations. METHODS: Forty four patients with atopic dermatitis who visited the Pediatric Allergy Clinic in Soonchunhyang University Hospital from December 2004 to April 2005 were enrolled. We evaluated the SCORAD scores. Then, fresh stools were collected and cultured to count colony numbers of L. casei, and blood were samples were taken to measure IFN-gamma, total IgE, specific IgE (house dust mites, milk, egg white, dog hair, soy bean), peripheral blood eosinophil percent, and ECP. We divided patients by two groups randomly. L. casei containing yoghurt was ingested by one group but not by the other group for 16 weeks. After that period, SCORAD scores, stool cultures and blood samples were reevaluated. RESULTS: Most patients who received L. casei experienced improvement of atopic dermatitis, but changes in SCORAD scores were not so significant compared with the other group. Just forty patients had their blood tested again (L. casei group was 21), and there were no statistical significances. There were also no significant changes of specific IgE, eosinophil percent, ECP, total IgE, and IFN-gamma levels, before and after. The colony counts of L. casei in stool which were cultured after investigation, were relatively high in the group with L. casei supplements. (P=0.03) Conclusion: The administration of L. casei in children with atopic dermatitis might be helpful to improve the colony counts of L. casei in intestines, and these increased L. casei are expected to act as a down-regulator of allergic inflammation, but more investigations should be conducted to reveal the precise mechanisms and possible complications.
Animals ; Child* ; Dermatitis, Atopic* ; Dogs ; Dust ; Egg White ; Eosinophils ; Hair ; Hematologic Tests ; Humans ; Hypersensitivity ; Immunoglobulin E ; Inflammation ; Intestines ; Lactobacillus casei* ; Lactobacillus* ; Lymphoid Tissue ; Milk ; Mites ; Probiotics ; Yogurt

Vaccine contains active components, adjuvants, stabilizers, preservatives, and trace components. Adverse reactions to vaccines are rarely reported. However, all of vaccine components may elicit adverse reaction including life-threatening event in susceptible individuals, therefore raising concerns regarding safety of vaccine still continue up to date. Hypersensitivity reaction to vaccines can be classified as allergic reaction to the vaccine component, pseudo-allergic reaction, and exacerbation of allergic diseases. Hypersensitivity reactions to vaccine components rarely occurred in the population-level, while severe hypersensitivity reaction such as anaphylaxis may be consequent result in susceptible individuals. Some of components such as ovalbumin, gelatin, yeast, and latex were considered as common causes of allergic reactions to the vaccine. However, the incidence or causes of vaccine related hypersensitivity reaction in Korea were not well known. The aims of this article are to review the literatures with hypersensitivity reactions related with vaccine components, to provide detailed information about major components of vaccines commonly used in Korea, and to provide the best way of vaccination in susceptible individuals.
Anaphylaxis ; Gelatin ; Hypersensitivity* ; Incidence ; Korea ; Latex ; Ovalbumin ; Vaccination ; Vaccines ; Yeasts

Allergic diseases such as asthma, allergic rhinitis, atopic dermatitis, and food allergy, are most common chronic, noncommunicable diseases in childhood. In the past few decades, the prevalence has increased abruptly worldwide. There are 2 possible explanations for the rising prevalence of allergic diseases worldwide, that an increased disease-awareness of physician, patient, or caregivers, and an abrupt exposure to unknown hazards. Unfortunately, the underlying mechanisms remain largely unknown. Despite the continuing efforts worldwide, the etiologies and rising prevalence remain unclear. Thus, it is important to identify and control risk factors in the susceptible individual for the best prevention and management. Genetic susceptibility or environments may be a potential background for the development of allergic disease, however they alone cannot explain the rising prevalence worldwide. There is growing evidence that epigenetic change depends on the gene, environment, and their interactions, may induce a long-lasting altered gene expression and the consequent development of allergic diseases. In epigenetic mechanisms, environmental tobacco smoke (ETS) exposure during critical period (i.e., during pregnancy and early life) are considered as a potential cause of the development of childhood allergic diseases. However, the causal relationship is still unclear. This review aimed to highlight the impact of ETS exposure during the perinatal period on the development of childhood allergic diseases and to propose a future research direction.
Asthma ; Caregivers ; Child ; Critical Period (Psychology) ; Dermatitis, Atopic ; Epigenomics ; Food Hypersensitivity ; Gene Expression ; Genetic Predisposition to Disease ; Humans ; Pregnancy ; Prevalence ; Rhinitis, Allergic ; Risk Factors ; Smoke* ; Tobacco Smoke Pollution ; Tobacco*

PURPOSE: Streptococcus pyogenes is an important cause of invasive diseases in children. We aimed to describe the clinical characteristics of invasive infections due to S. pyogenes in children in Korea. METHODS: A retrospective study of children under 18 years of age with invasive infections due to S. pyogenes at Seoul National University Children's Hospital between March 1992 and December 2012, and Seoul National University Bundang Hospital between March 2003 and December 2012 was conducted. Demographic factors, clinical characteristics, laboratory findings, treatment, mortality and morbidity of all patients were reviewed. RESULTS: A total of 30 among 36 cases identified as invasive disease due to S. pyogenes were available for review. There was a predominance for male subjects (male:female=2.75:1). The median age was 50 months (range 12 days to 15 years) and 53.3% were under 5 years of age. Skin and soft tissue infections (9/30, 30.0%), bacteremia without identified focus (4/30, 13.3%) and bone and joint infections (6/30, 20.0%) were the most frequent clinical presentations. Streptococcal toxic shock syndrome (3/30, 10.0%) pulmonary, abdomen and central nervous system infections (2/30, 6.7%) were also seen. There was a peak in number of patients in year 2012 (9/30, 30.0%). There were no cases of mortality. Erythromycin and clindamycin resistance rates were low by 3.8% and 7.5%, respectively. CONCLUSION: We studied the clinical presentations of invasive infections due to S. pyogenes during the past 20 years in Korean children. The findings of this study help us understand the characteristics of the disease, enhancing early recognition and prompting adequate antibiotic therapy which is important in reducing morbidity and mortality.
Abdomen ; Bacteremia ; Bacterial Infections ; Central Nervous System Infections ; Child* ; Clindamycin ; Demography ; Erythromycin ; Humans ; Joints ; Korea ; Male ; Mortality ; Retrospective Studies ; Seoul ; Shock, Septic ; Skin ; Soft Tissue Infections ; Streptococcus pyogenes*

PURPOSE: This study was performed to evaluate MR signal intensity(SI) of calcification and to assess the capability of MRI in detection of various intracranial calcifications. MATERIALS AND METHODS: The MR findings and ROI value of experimental model of calcium carbonate suspension according to each concentration (20, 35, 50%) and diameter (1-10 mm) and hydroxyapatite suspension according to each concentration (10, 20, 30, 40, 50%) were analyzed. A specimen of calcification in cranio-pharyngioma was analyzed for its composition by XRD(X-ray diffractometer) and ICP(inductively coupled plasma) methods. MRI of 34 patients with intracranial calcifications were retrospectively analyzed for signal intensity of the calcification and its capability to detect calcifications according to size, location, and contrast with adjacent lesion. RESULTS: The calcium carbonate phantom with larger diameter and low concentration showed lower signal intensity on T2 than TlWl. Hydroxyapatite phantom showed high signal intensity in 10-30% concentration and low signal intensity in 40-50% concentration on T1 weighted image. The 5 cases of 34 intracranial calcifications showed high signal intensity on T1 weighted image. The capability of MRI in the detection of intracranial calcifications decreased in the circumstances such as small size(<2.5mm) and intraventricular location. Although the size of calcification was small, the detection was easy in the good contrast with adjacent lesion. However, the detection of the small sized calcification was easy if the contrast with adjacent lesion was good. CONCLUSION: lntracranial calcification shows generally low signal intensity on T1 and T2 weighted image with the exception of occasional high SI on TlWl. Detection of intracranial calcification in MRI is affected by its composition, size, location, and contrast with adjcent lesion.
Calcium Carbonate ; Durapatite ; Humans ; Magnetic Resonance Imaging* ; Models, Theoretical ; Retrospective Studies