Kangmo Ahn

The role of air pollutants in atopic dermatitis

Atopic dermatitis (AD) is a chronic relapsing inflammatory skin disease and a growing health concern, especially in children, because of its high prevalence and associated low quality of life. Genetic predisposition, environmental triggers, or interactions between them contribute to the pathophysiology of AD. Therefore, it is very important to identify and control risk factors from the environment in susceptible subjects for successful treatment and prevention. Both indoor and outdoor air pollution, which are of increasing concern with urbanization, are well-known environmental risk factors for asthma, whereas there is relatively little evidence in AD. This review highlights epidemiologic and experimental data on the role of air pollution in patients with AD. Recent evidence suggests that a variety of air pollutants, such as environmental tobacco smoke, volatile organic compounds, formaldehyde, toluene, nitrogen dioxide, and particulate matter, act as risk factors for the development or aggravation of AD. These air pollutants probably induce oxidative stress in the skin, leading to skin barrier dysfunction or immune dysregulation. However, these results are still controversial because of the low number of studies, limitations in study design, inaccurate assessment of exposure and absorption, and many other issues. Further research about the adverse effects of air pollution on AD will help to expand our understanding and to establish a better strategy for the prevention and management of AD.

The incidence and risk factors of immediate type food allergy during the first year of life in Korean infants: a birth cohort study

To cite this article: Kim J, Chang E, Han Y, Ahn K, Lee S‐I. The incidence and risk factors of immediate type food allergy during the first year of life in Korean infants: a birth cohort study. Pediatric Allergy Immunology 2011; 22: 715–719.

A randomized trial of Lactobacillus plantarum CJLP133 for the treatment of atopic dermatitis

There have been considerable disagreements regarding the therapeutic effects of probiotics in atopic dermatitis (AD). We performed this study to examine whether the oral administration of Lactobacillus plantarum CJLP133 improves pediatric AD.

Sensitization to aeroallergens in Korean children: a population-based study in 2010.

We performed this study to assess the prevalence of sensitization to aeroallergens and to analyze the difference between prevalence rates according to childrens ages and residential areas. In this nationwide cross-sectional study, first grade students of 45 elementary schools and 40 middle schools were randomly selected, and skin prick tests were performed for 18 inhalant allergens between October and November 2010. Of 7,829 analyzed subjects, 3,753 (47.9%) were sensitized to at least one aeroallergen. Sensitization to Dermatophagoides farinae was found to be the most prevalent in elementary schoolchildren (32.4%), followed by Dermatophagoides pteronyssinus, Tyrophagus putrescentiae, Japanese hop, and oak. In middle schoolchildren, D. pteronyssinus yielded the highest prevalence (42.7%), followed by D. farinae, T. putrescentiae, Japanese hop, and cat. In middle schoolchildren, the sensitization rate to aeroallergens in metropolitan, urban, and rural areas was 57.2%, 54.3%, and 49.8%, respectively (P = 0.019). In this age group, the sensitization rate in low, middle, high, and very high income groups was 53.8%, 51.8%, 59.0%, and 59.6%, respectively (P = 0.002). In conclusion, the sensitization rate is 47.9% and house dust mite is the most prevalent allergen in the pediatric population in Korea. The rate is higher in metropolitan areas and the highest income group than in rural areas and low income groups.

Characterization of Staphylococcus aureus nasal carriage from children attending an outpatient clinic in Seoul, Korea.

Nasal swabs were collected to isolate S. aureus in 296 children, who visited the pediatrics department with a variety of symptoms. Staphylococcus aureus was isolated from 95 children (32.1%). Of the isolates, 18 were methicillin-resistant S. aureus (MRSA) (18.9%). Antimicrobial susceptibility testing was performed for all S. aureus cultured and the molecular characteristics were investigated. Forty-nine spa types were identified among the S. aureus isolates, and were classified into 13 spa groups (A-L). The most prevalent clone (34 isolates, 35.8%) belonged to the spa group B (spa repeat motif, WG/FKAOMQ), which corresponded to sequence type 30 (ST30) and its variants. Sixteen different spa types, within the spa group B, suggested that this group has evolved over a long period of time. In addition, all S. aureus isolates belonging to the spa group B were methicillin-susceptible, indicating that this group might represent successful adaptation of this clone in the community setting with low antibiotic pressure. The most frequently found clone in the MRSA group was spa group C (spa repeat motif, DMGGM) and SCCmec type IVA, which represented half of the MRSA isolates and corresponded to ST72. ST5-MRSA-II, the most prevalent MRSA clone in Korean hospitals, was found in only two isolates. These findings suggest that strains of S. aureus nasal carriage in Korean children visiting an outpatient pediatric department were different from the strains identified in hospital infections.

The Influence of the Time and Temperature of Heat Treatment on the Allergenicity of Egg White Proteins

Purpose The present study was performed to determine the factor, either duration or the temperature of heat treatment, exerting maximal and significant influence on the composition and allergenicity of egg white (EW) proteins. Methods Raw EW and 4 kinds of heated EW (fried EW, boiled EW for 10 minutes, boiled EW for 30 minutes, and baked EW for 20 minutes at 170℃) were prepared, and subsequently protein extraction was carried out. The proteins were separated by SDS-PAGE, and then immunoglobulin E (IgE) immunoblots were performed with the sera of 7 egg-allergic patients. Furthermore, the antigenic activities of ovalbumin (OVA), ovomucoid (OM), and ovotransferrin (OT) in different EW samples were measured by inhibition enzyme-linked Immuno-sorbent assay (ELISA). Results In SDS-PAGE analysis, the intensity of the protein band at 45 kD (corresponding to OVA) decreased significantly in boiled EW (30 minutes) and baked EW, but no change was observed in the case of boiled EW for 10 minutes. In IgE immunoblots, the IgE response to 34-50 kD (OM and OVA) in boiled EW for 30 minutes decreased significantly, when compared with raw EW and other heated EWs. In inhibition ELISA, a significant decrease in the OVA antigenic activity was observed in boiled EW for 30 minutes amongst other heated EW samples. However, OM antigenic activity in all kinds of heated EW including boiled EW for 30 minutes did not reduce after heat treatment. The OT antigenic activity nearly disappeared in heated EWs except in the case of boiled EW for 10 minutes. Conclusions Amongst 4 kinds of heated EWs, the boiled EW for 30 minutes showed the most significant changes both in composition and reduction in allergenicity. Our results revealed that the duration of heat treatment had more influence on the composition and allergenicity of EW proteins than the temperature.

Inhalation Toxicity of Humidifier Disinfectants as a Risk Factor of Children's Interstitial Lung Disease in Korea: A Case-Control Study

Background The occurrence of numerous cases of interstitial lung disease in children (chILD) every spring in Korea starting in 2006 raised suspicion about a causal relationship with the use of humidifier disinfectants (HDs). The aim of this study was to evaluate the association between HD use and the risk of chILD. Methods This retrospective, 1∶3 matched case-control study consisted of 16 cases of chILD that had developed between 2010 and 2011. The three groups of parallel controls (patients with acute lobar pneumonia, asthma, and healthy children) were matched by age, gender, and index date. Indoor/outdoor environmental risk factors, including HD use, were investigated by asking the guardians to complete a questionnaire. Results The median age of the affected children (43.8% male) was 26 months (18.25–36.25). The chILD group did not differ significantly from the control groups with respect to socio-demographic and clinical variables. Indoor and outdoor environmental factors were not associated with a risk of chILD. However, the previous use of HDs (OR; 2.73. 95% CI; 1.41–5.90, P = 0.00) were independently associated with an increased risk. Conclusions This study showed that HDs, which are widely used in South Korea in the winter season, independently increased the risk of chILD in spring. Therefore, continuous monitoring and, if needed, changes in policy are essential to prevent and control pediatric diseases caused by toxic chemicals.

Prevalence of Atopic Dermatitis in Korea: Analysis by Using National Statistics

We attempted to investigate the prevalence of atopic dermatitis (AD) in Korea by using national statistics. Data on AD patients who received medical service at least once a year from 2003 through 2008 were collected from health insurance research team of National Health Insurance Corporation. Data of estimated populations during the same period were obtained from the Statistics Korea. In 2008, the prevalence of AD was 26.5% in aged 12-23 months and decreased substantially to 7.6% at age 6 yr, 3.4% at age 12 yr and to 2.4% at age 18 yr. In males, the prevalence was higher than females until 2 yr of age, while the opposite was shown in children aged 2 yr or older. In children aged less than 24 months, the prevalence of AD has increased from 19.8% to 23.8% between the years 2003 and 2008, while the prevalence showed no increase in the older age group. In conclusion, the prevalence of AD in 2008 peaked during infancy up to 26.5% and decreased thereafter. Our findings also suggest that increasing prevalence of AD in children less than 24 months might be responsible for the recent increase in the prevalence of AD in Korean children.

Prevalence of immediate-type food allergy in Korean schoolchildren: a population-based study.

Although the prevalence and causes of food allergy (FA) vary by geographic location, large well-designed epidemiological studies in Asia are lacking. The purpose of this study was to evaluate the prevalence of immediate-type FA in the general population of Korean schoolchildren. A population-based, cross-sectional study was conducted in 2010 using a stratified two-stage cluster-sampling design. In this survey, children aged 6-7 years and 12-13 years were randomly selected, and the presence of FA was determined by a questionnaire survey and assessment of specific IgE. After adjustment for missing data, 3907 children aged 6-7 years and 3975 students aged 12-13 years who completed the questionnaire were included in this study. In children aged 6-7 years, the prevalence of confirmed immediate-type FA was 0.3%, and the prevalence of possible immediate-type FA was 0.3%. By contrast, 0.6 and 1.0% of children aged 12-13 years had confirmed immediate-type FA and possible immediate-type FA, respectively. In 6- to 7-year-old children, egg was the most frequent causative food associated with a confirmed or possible immediate-type FA. In 12- to 13-year-old children, crustaceans were the most frequent cause of confirmed immediate-type FA, and fruit was most frequently involved in possible immediate-type FA. This is the first nationwide population-based study of FA in Korean schoolchildren. Unlike in western countries, the prevalence of immediate-type FA seems to be low. In 12- to 13 year-old children with confirmed immediate-type FA, peanuts/tree nuts are not common causes, whereas crustaceans are frequent triggers.

A proposal: Atopic Dermatitis Organizer (ADO) guideline for children

Atopic dermatitis (AD) is the most common chronic inflammatory skin disorder in children, with a worldwide cumulative prevalence in children of 8-20%. The number of AD patients is beyond the level that can be dealt with at clinics and it is time to make an effort to reduce the number of AD patients in the community. Thus, caregivers and all persons involved with AD management, including health care providers, educators, technologists and medical policy makers, should understand the development and the management of AD. Although a number of guidelines such as Practical Allergy (PRACTALL) report have been developed and used, community understanding of these is low. This is probably because there are still remarkable differences in management practices between specialists and between countries and most of the reported guidelines have been prepared for physicians. From the viewpoint of providing a basis for a multidisciplinary team approach, easily comprehensible guidelines for organizing treatment of AD, i.e. an Atopic Dermatitis Organizer (ADO), are required. guidelines should be simple and well organized. We suggest an easy approach with a new classification of AD symptoms into early and/or progressive lesions in acute and/or chronic symptoms. The contents of this ADO guideline basically consist of 3 steps approaches: conservative management, topical anti-inflammatory therapy, and systemic anti-inflammatory therapy.