Air pollution does harm to the respiratory tracts. Fine particulate matter (PM2.5) attacks the lung directly passing through mucosal ciliary clearance, causes new-onset asthma, or exacerbates asthma symptoms in children. Oxidative stresses, immunologic changes, allergic sensitization, and epigenetic modification are associated with bronchial asthma. Furthermore, it causes respiratory tract infection and lung function decline. We have to protect the children who are more vulnerable to PM2.5 than adults. We will investigate individual exposure, influences by the components of air pollution, and genetic susceptibility. (Allergy Asthma Respir Dis 2019;7:116-121)

Obstructive sleep apnea syndrome (OSAS) is the most severe form of obstructive sleep-disordered breathing. It can produce cardiovascular problems, growth retardation, cognitive deficits, and behavioral problems such as attention deficit/hyperactivity symptoms in children. The diagnostic gold standard for OSAS is overnight polysomnography, but it is expensive, time-consuming, and labor intensive, and is conducted by specialized centers which have trained personnel. Therefore, sleep questionnaires as screening tools for OSAS was developed. The benefits of sleep questionnaires are easy/quick application and low cost. The objective of this review is to describe several available pediatric sleep questionnaires which are helpful in screening OSAS. (Allergy Asthma Respir Dis 2019;7:122-128)

Purpose: Recently, the incidence of refractory Mycoplasma pneumoniae (MP) pneumonia has increased in Korea. Given that its early diagnosis is helpful in selection of the treatment, this study aimed at investigating the value of the antimycoplasma antibody (IgM) for early diagnosis of MP pneumonia.
Methods: A total of 315 children admitted with MP pneumonia from September 2015 to May 2016 were investigated with the IgM and polymerase chain reaction (PCR) for the diagnosis of MP pneumonia. Specifically, patients were grouped into nonrefractory respiratory MP and refractory MP groups according to their response to macrolide therapy.
Results: In the 44 PCR-negative seroconversed children, seroconversed IgM was more frequent in the refractory MP group compared with the nonrefractory respiratory MP group with statistical significance (P<0.001). In the 264 IgM-positive children, the time of antibody reaction was more delayed in the refractory MP group compared to the nonrefractory respiratory MP group with statistical significance (P<0.001).
Conclusion: This study showed that there was a higher incidence of seroconversed IgM and delayed antibody reaction in the refractory MP group. In children with suspect MP pneumonia, follow-up studies of antibody are necessary, even through initial antibody and PCR showed negative findings. In addition, this result may suggest that the diagnosis of refractory MP pneunomia will be helpful in establishing the strategy of the treatment. (Allergy Asthma Respir Dis 2019;7:129-136)

Purpose: Tracheostomy has been increasingly performed in children, along with the improvements in neonatal and pediatric intensive care. The objective of this study was to describe the indications, comorbidities, complications, and outcomes of tracheostomy in children in a tertiary hospital.
Methods: This was a retrospective study of children who required tracheostomy in a tertiary hospital in Korea between April 2009 and March 2018. The medical records of the patients were retrospectively reviewed and analyzed.
Results: A total of 41 children underwent tracheostomy. The median age of the patients was 11.9 months (interquartile range [IQR], 5.4-179.2 months), and 20 (48.8%) were boys. Tracheostomy was performed commonly in respiratory disease (12 [29.2%]) and neurologic disease (17 [41.5%]). The indications of tracheostomy differed according to patient age. There were trends toward longer length of intubation (median, 78.0 days; IQR, 36.0-185.0 days), longer hospitalization (213.3±154.5 days), higher decannulation rate (32.0%) and lower complications (12.0%) in patients who received tracheostomy as an infant/toddler.
Conclusion: Regarding pediatric tracheostomy in this study, there were bimodal age distribution and consequential clinical differences depending on patient age. (Allergy Asthma Respir Dis 2019;7:137-141)

Purpose: We aimed to analyze the frequency of eosinophilia-associated diseases and to search for possible markers that may be useful for their differential diagnosis.
Methods: We retrospectively reviewed the medical records of 148 patients with peripheral blood eosinophil count of more than 500/μL who visited the Allergy Department of Chonnam National University Hospital for the first time from January to December 2016. Blood eosinophilia was categorized as mild (<1,500/μL), moderate (1,500-5,000/μL), and severe (>5,000/μL).
Results: Blood eosinophilia was mostly caused by allergic diseases (41.9%), parasitic infestation (23.6%), and drug allergy (19.6%). Eosinophil count was higher in patients with parasitic infestation (P<0.01), drug allergy (P<0.01), hypereosinophilic syndrome (HES, P<0.001), or eosinophilic granulomatosis with polyangiitis (EGPA, P<0.001) than in those with allergic diseases. The eosinophilic cationic protein level was higher in patients with HES than in those with allergic diseases (P<0.05) and parasitic infestation (P<0.05). The total IgE level was lower in patients with HES than in those with parasitic infestation (P<0.05) and EGPA (P<0.05). The vitamin B12 level was higher in patients with HES than in those with parasitic infestation (P<0.05). There was no statistically significant difference in tryptase levels between the groups. The most common cause of mild eosinophilia was allergic diseases (59.8%), followed by parasitic infestation (22.7%) and drug allergy (13.4%). The common causes of moderate eosinophilia were drug allergy (37.8%), parasitic infestation (29.7%), and allergic diseases (10.8%). The common causes of severe eosinophilia were EGPA (28.6%), HES (21.4%), parasitic infestation (14.3%), and drug allergy (14.3%).
Conclusion: Common causes of blood eosinophilia in patients who visit the allergy department are allergic diseases, parasitic infestation, and drug allergy. Several markers, including eosinophil count, total IgE, and vitamin B12, may be useful for the differential diagnosis of eosinophilia-associated diseases. (Allergy Asthma Respir Dis 2019;7:142-149)

Purpose: Atopic dermatitis (AD) is the most common chronic and relapsing inflammatory skin disease with skin barrier defects and altered immune responses. Chronic inflammation leads to irreversible fibrosis in the skin and there is no treatment to completely abolish the inflammation and fibrosis. To prevent or treat the chronic process of AD, it is necessary to develop a murine model of AD that reflects the chronic process to identify the mechanism. The aims of this study were to develop a chronic AD model with a crude extract Aspergillus fumigatus (Af) antigen.
Methods: We applied Af extract (40 μg) epicutaneously to the dorsal skin of BALB/c mice for 5 consecutive days per week during a period of 5 weeks for a chronic AD model, and 5 consecutive days repeatedly with 2 weeks interval for an acute AD model.
Results: The clinical score and transepidermal water loss were more increased in the chronic AD model than in the acute AD model. Histologic findings showed that more increased epidermal thickness, neutrophil infiltration and hyperkeratosis in the chronic model than in the acute model. Skin fibrosis was more prominent in the chronic model than in the acute model. The mRNA expression levels of transforming growth factor (TGF)-β, thymic stromal lymphopoietin, and interleukin-33 were increased in the skin of the chronic model compared to the acute model. The levels of total IgE, Af-specific IgE, IgG1, and IgG2a were significantly increased in the chronic model compared to controls.
Conclusion: The Af-induced chronic AD model showed prominent fibrosis and increased TGF-β expression in the skin, which suggests that these models may be useful in the research for the mechanism of the chronic process in AD. (Allergy Asthma Respir Dis 2019;7:150-157)

Filamin A is an actin-binding protein and, in humans, is encoded by FLNA gene in the long arm of X chromosome. Filamin A plays a role in the formation of cytoskeleton by crosslinking actin filaments in cytoplasm. FLNA mutations affect cytoskeletal regulatory processes and cellular migrating abnormalities that result in periventricular heterotopia. A 5-month-old girl was hospitalized because of breathing difficulty and was diagnosed as having periventricular heterotopia with laryngomalacia, cricopharyngeal incoordination, pulmonary hypertension, and chronic lung disease. A genetic test was performed to find the cause of periventricular heterotopia, and FLNA gene mutation (c.5998+1G>A) was confirmed for the first time in Korea. After discharge, she developed respiratory failure due to a viral infection at 8 months of her age. In spite of management with mechanical ventilation, she died of pneumothorax and pulmonary hemorrhage. Herein, we report a case of FLNA gene mutation who presented with periventricular nodular heterotopia with respiratory insufficiency. (Allergy Asthma Respir Dis 2019;7:158-164)

Primary ciliary dyskinesia (PCD) is a genetically heterogeneous disease affecting motile cilia. A female neonate was hospitalized with respiratory distress 72 hours after birth and showed concurrent situs inversus. She was identified to have compound heterozygous mutations in DNAH5: c.5647C>T, p.Arg1883Ter (nonsense mutation) and c.10810dupA, p.Ile3604AsnfsTer2 (frameshift mutation). Sanger sequencing confirmed that they were inherited from her father and mother, respectively, and she was diagnosed with PCD. The c.10810dupA is a novel DNAH5 mutation that has never been reported. To the best of our knowledge, this is the first report describing DNAH5 mutations in a Korean patient with PCD. (Allergy Asthma Respir Dis 2019;7:165-169)