Perinatal Prognostic Factors for Congenital Diaphragmatic Hernia: A Korean Single-Center Study

Purpose@#This study aimed to identify prognostic factors based on treatment outcomes for congenital diaphragmatic hernia (CDH) at a single-center and to identify factors that may improve these outcomes. @*Methods@#Thirty-five neonates diagnosed with CDH between January 2011 and December 2021 were retrospectively analyzed. Pre- and postnatal factors were correlated and analyzed with postnatal clinical outcomes to determine the prognostic factors. Highest oxygenation index (OI) within 24 hours of birth was also calculated. Treatment strategy and outcome analysis of published literatures were also performed. @*Results@#Overall survival rate of this cohort was 60%. Four patients were unable to undergo anesthesia and/or surgery. Three patients who commenced extracorporeal membrane oxygenation (ECMO) post-surgery were non-survivors. Compared to the survivor group, the non-survivor group had a significantly higher occurrence of pneumothorax on the first day, need for high-frequency ventilator and inhaled nitric oxide use, and high OI within the first 24 hours. The non-survivor group showed an early trend towards the surgery timing and a greater number of patch closures. Area under the receiver operating characteristic curve was 0.878 with a sensitivity of 76.2% and specificity of 92.9% at an OI cutoff value of 7.75. @*Conclusion@#OI within 24 hours is a valuable predictor of survival. It is expected that the application of ECMO based on OI monitoring may help improve the opportunity for surgical repair, as well as the prognosis of CDH patients.

Implementing the Golden Hour Protocol to Improve the Clinical Outcomes in Preterm Infants

Purpose@#Since premature infants are sensitive to the changes in blood glucose levels and body temperature, maintaining these parameters is important to avoid the risk of infections. The authors implemented the Golden Hour protocol (GHP) that aims to close the final incubator within one hour of birth by implementing early treatment steps for premature infants after birth, such as maintaining body temperature, securing airway, and rapidly administering glucose fluid and prophylactic antibiotics by securing breathing and rapid blood vessels. This study investigated the effect of GHP application on the short- and long-term clinical outcomes. @*Methods@#We retrospectively analyzed the medical records between 2017 and 2018 before GHP application and between 2019 and 2020 after GHP application in preterm infants aged 24 weeks or older and those aged less than 33 weeks who were admitted to the neonatal intensive care unit. @*Results@#Overall, 117 GHP patients and 81 patients without GHP were compared and analyzed. Peripheral vascularization time and prophylactic antibiotic administration time were shortened in the GHP-treated group (P=0.007 and P=0.008). In the short-term results, the GHP-treated group showed reduced hypothermia upon arrival at the neonatal intensive care unit (P=0.002), and the blood glucose level at 1 hour of hospitalization was higher (P=0.012). Furthermore, the incidence of neonatal necrotizing enteritis decreased (P=0.043). As a long-term result, the incidence of BPD was reduced (P=0.004). @*Conclusion@#We confirmed that applying GHP improved short- and long-term clinical outcomes in premature infants aged <33 weeks age of gestation, and we expect to improve the treatment quality by actively using it for postnatal treatment.

Neurodevelopmental Outcomes of Very-Low-Birth-Weight Infants without Severe Brain Lesions and Impact of Postnatal Steroid Use: A Single-Center Korean Study

Purpose@#We used the Bayley Scales of Infant and Toddler Development (BSID)-III to analyze the incidence and risk factors of developmental delay in very-low-birth-weight infants without severe brain lesions. We further examined the correlation between the cumulative dexamethasone dose and developmental assessment results. @*Methods@#We retrospectively analyzed data of preterm infants (birth weight <1,500 g) admitted to our neonatal intensive care unit between January 2014 to December 2020. The BSID-III scores obtained between the corrected ages of 12 and 24 months and after 24 months were analyzed. Developmental delay was defined as a composite score of <85 for the cognition, language, and motor domains. Univariate and multivariate analyses of developmental delay risk factors and developmental changes from the first to second BSID-III were performed. Correlations between the accumulated dexamethasone dose used for bronchopulmonary dysplasia (BPD) and the first and second test scores were analyzed. @*Results@#Seventy-one and thirty-six infants completed the first and second tests, respectively. In both tests, developmental delay was most commonly observed in the language domain (26.8%, 47.2%). In multivariate analysis, mild BPD was identified as a developmental delay risk factor (P<0.05), whereas prenatal steroid use reduced the developmental delay risk (P<0.05). All domain scores were lower in the second test than in the first test. The cognition and language domain scores in the second test decreased with increasing cumulative dexamethasone doses. @*Conclusion@#Very-low-birth-weight infants typically experience language delay, which can persist as they age.

Congenital Syphilis in Neonate: A Single Center Study for 10 Years

Purpose@#Syphilis infections are becoming more prevalent in the Republic of Korea, and inadequately treated syphilis can lead to congenital syphilis (CS) in newborns. This study aimed to analyze the clinical manifestations of syphilis in mothers and newborns and to make suggestions to improve disease prognosis. @*Methods@#This single-center study was performed between August 2009 and August 2019 and included 29 newborns with CS. We retrospectively evaluated the clinical features, rapid plasma reagin (RPR) card test, fluorescent treponemal antibody absorption test (FTA-ABS), morbidity, and treatment regimen of all the syphilis-affected mothers and their newborns. @*Results@#At the time of delivery, mean maternal age was 29.0±6.1 years old, and newborn gestational age was 38.0 weeks. In cases when syphilis was confirmed during the second and third trimesters of pregnancy, the newborn with CS had morbidity (p=0.004). The mean RPR titer was related to morbidity (p= 0.036). Positive results of FTA-ABS IgM (p<0.001) and pleocytosis in the cerebrospinal fluid (CSF) (p= 0.020) also increase morbidity. The most common symptoms were desquamation and skin rash, followed by hepatomegaly, neurodevelopmental disability, and bone abnormalities. The highest number of CS cases per 1,000 live births in this hospital was in 2014. @*Conclusion@#CS is a preventable and treatable disease if physicians detect symptoms and provide appropriate treatment through RPR examinations during every trimester. General practitioners should be widely trained on various aspects including early detection, formal treatment, and regular follow-up. Additionally, medical services should be provided for the entire childbearing population regardless of the socioeconomic status.

Congenital Syphilis in Neonate: A Single Center Study for 10 Years

Purpose@#Syphilis infections are becoming more prevalent in the Republic of Korea, and inadequately treated syphilis can lead to congenital syphilis (CS) in newborns. This study aimed to analyze the clinical manifestations of syphilis in mothers and newborns and to make suggestions to improve disease prognosis. @*Methods@#This single-center study was performed between August 2009 and August 2019 and included 29 newborns with CS. We retrospectively evaluated the clinical features, rapid plasma reagin (RPR) card test, fluorescent treponemal antibody absorption test (FTA-ABS), morbidity, and treatment regimen of all the syphilis-affected mothers and their newborns. @*Results@#At the time of delivery, mean maternal age was 29.0±6.1 years old, and newborn gestational age was 38.0 weeks. In cases when syphilis was confirmed during the second and third trimesters of pregnancy, the newborn with CS had morbidity (p=0.004). The mean RPR titer was related to morbidity (p= 0.036). Positive results of FTA-ABS IgM (p<0.001) and pleocytosis in the cerebrospinal fluid (CSF) (p= 0.020) also increase morbidity. The most common symptoms were desquamation and skin rash, followed by hepatomegaly, neurodevelopmental disability, and bone abnormalities. The highest number of CS cases per 1,000 live births in this hospital was in 2014. @*Conclusion@#CS is a preventable and treatable disease if physicians detect symptoms and provide appropriate treatment through RPR examinations during every trimester. General practitioners should be widely trained on various aspects including early detection, formal treatment, and regular follow-up. Additionally, medical services should be provided for the entire childbearing population regardless of the socioeconomic status.

Identification of a novel variant in the PHEX gene using targeted gene panel sequencing in a 24-month-old boy with hypophosphatemic rickets

Familial hypophosphatemic rickets (FHR) is a disorder characterized by phosphate wasting and hypophosphatemia due to defects in renal phosphate transport regulation. There are 4 known inherited forms of FHR that differ in their molecular causes. Very few studies have been conducted that focused on the molecular analysis of FHR in Koreans. Eighteen mutations of the PHEX gene have been identified to this date in Korea. Herein, we report the clinical case of a 24-month-old boy presenting with bowed legs and short stature. The biochemical profile showed hypophosphatemia with decreased tubular reabsorption of phosphate. Several family members were identified with short stature and genu varum. Therefore, he was diagnosed with FHR. To identify the molecular causes of FHR, we performed targeted gene panel sequencing and found a novel hemizygous missense variant, c.1949T>C (p.Leu650Pro), in the PHEX gene. This variant was also detected in the boy’s mother who exhibited genu varum and short stature.

An A627V-activating mutation in the thyroid-stimulating hormone receptor gene in familial nonautoimmune hyperthyroidism

Nonautoimmune hyperthyroidism is a very rare cause of congenital hyperthyroidism that is usually caused by an activating mutation in the thyroid-stimulating hormone receptor (TSHR) gene. In this report, we describe a case of nonautoimmune hyperthyroidism in a patient with TSHR mutation. Our patient was the younger of a set of twins born at 36 weeks and 6 days of gestation. The patient was noted to be more irritable than the older twin at 80 days of age, and the mother was taking methimazole for Graves’ disease that had been diagnosed 12 years prior. Therefore, a thyroid function test was conducted for the patient. The results revealed subclinical hyperthyroidism, and tests of antithyroglobulin antibody, antithyroid peroxidase antibody, and anti-thyroid-stimulating hormone (TSH) receptor antibody were all negative. During follow-up, at around 4 months of age, free T4 increased to 2.89 ng/dL, and TSH was still low at 0.01 μIU/mL; therefore, 3 mg/day of methimazole was initiated. Whole-exome sequencing showed a heterozygous variant of c.1800C>T (p.Ala627Val) in the TSHR gene. Testing in the family confirmed an identical variant in the patient's mother, leading to diagnosis of familial nonautoimmune hyperthyroidism inherited in an autosomal dominant pattern. This is the second report of A627V confirmed as a germline variant.

An A627V-activating mutation in the thyroid-stimulating hormone receptor gene in familial nonautoimmune hyperthyroidism

Nonautoimmune hyperthyroidism is a very rare cause of congenital hyperthyroidism that is usually caused by an activating mutation in the thyroid-stimulating hormone receptor (TSHR) gene. In this report, we describe a case of nonautoimmune hyperthyroidism in a patient with TSHR mutation. Our patient was the younger of a set of twins born at 36 weeks and 6 days of gestation. The patient was noted to be more irritable than the older twin at 80 days of age, and the mother was taking methimazole for Graves’ disease that had been diagnosed 12 years prior. Therefore, a thyroid function test was conducted for the patient. The results revealed subclinical hyperthyroidism, and tests of antithyroglobulin antibody, antithyroid peroxidase antibody, and anti-thyroid-stimulating hormone (TSH) receptor antibody were all negative. During follow-up, at around 4 months of age, free T4 increased to 2.89 ng/dL, and TSH was still low at 0.01 μIU/mL; therefore, 3 mg/day of methimazole was initiated. Whole-exome sequencing showed a heterozygous variant of c.1800C>T (p.Ala627Val) in the TSHR gene. Testing in the family confirmed an identical variant in the patient's mother, leading to diagnosis of familial nonautoimmune hyperthyroidism inherited in an autosomal dominant pattern. This is the second report of A627V confirmed as a germline variant.

Bilateral Acute Retinal Necrosis and Encephalomalacia Due to Herpes Simplex Virus Infection in a Premature Infant

Herpes simplex virus (HSV) is a common pathogen, that causes a broad spectrum of diseases, ranging from minor skin infections to severe encephalitis and widespread infections. Acute retinal necrosis (ARN), one of the most serious manifestations of HSV infection, is defined as a rapidly progressing necrotizing retinopathy that presents discrete areas of circumferential retinal necrosis, along with signs of uveitis, vitreitis, and retinal vasculitis. We encountered a case of a female infant, born at 33 weeks of gestation with a body weight at birth of 2,080 g, who had ARN and encephalomalacia due to HSV infection. ARN associated with HSV infection should be suspected when nonspecific retinal exudates are observed in neonates, especially preterm infants.

Risk Factors for Delayed Hyperthyrotropinemia in Late Preterm Infants

PURPOSE: This study aimed to investigate the prevalence of delayed thyroid dysfunction based on iodine disinfectant use and to analyze associated risk factors.METHODS: A retrospective study was conducted on late preterm infants admitted to the neonatal intensive care unit between January 2010 and June 2018, who underwent neonatal thyroid screening (NTS) and ≥2 thyroid function tests (TFTs). NTS was performed 3 days after birth, with at least two TFTs 1 week and 2 to 4 weeks after birth. To distinguish between normal and dysfunctional thyroid levels, we reviewed TFT results at 2 to 4 weeks and examined possible risk factors for the development of thyroid dysfunction.RESULTS: Of 295 late preterm infants, 262 were enrolled with a mean gestational age and birth weight of 34.8±0.7 weeks and 2,170±454 g, respectively. A total of 7.6% developed hyperthyrotropinemia at the age of 24.3±14.6 days (range, 12 to 69). The incidence of hyperthyrotropinemia during iodine use was approximately 12.6%, while that during discontinuation was 2.4% (P=0.002). Multivariate analysis revealed that small for gestational age (SGA), iodine disinfectant use, and abnormal NTS results were significant risk factors for delayed hyperthyrotropinemia (adjusted odds ratio [AOR]: 4.27, P=0.008; AOR: 8.24, P=0.003; and AOR: 7.80, P=0.002, respectively).CONCLUSION: Delayed hyperthyrotropinemia was prevalent in late preterm infants exposed to topical iodine and those identified as being SGA. Secondary TFTs should be considered 2 to 4 weeks after birth for this population at risk.

Clinical Implication of Surgically treated Abdominoperineal Soild Tumor in the Newborn : A Single-Center Experience

PURPOSE: Abdominoperineal solid tumors presenting in neonates often require surgical intervention during the neonatal period. Although we report our single-center experience, this study would be meaningful to understand the clinical implications of these neoplasms. METHODS: We retrospectively reviewed and analyzed the clinical data and characteristics of 22 patients (≤28 days old) diagnosed with histopathologically confirmed abdominoperineal solid neoplasms (benign or malignant) after surgical resection. RESULTS: The mean gestational age and postnatal age at the time of operation were 38.3±1.8 weeks and 13.5±8.3 days, respectively. Most patients (18/22, 81.8%) were diagnosed during antenatal care visits; however, 4 (18.2%) were identified after birth. The mean tumor size was 6.4×5.3 cm (3.5–17.0 cm), and tumors occurred most frequently within the sacrococcygeal region (8/22, 36.4%). Histopathologically, 14 patients (63.6%) demonstrated benign tumors and 8 (36.4%) demonstrated malignant tumors. Germ cell tumors and hepatoblastomas were the most commonly observed tumors. Fortunately, all patients showed a localized pattern of tumor involvement without distant metastasis. No recurrence or mortality was observed during the follow-up period (mean 66.4±44.2 months). CONCLUSION: Abdominoperineal solid tumors occurring in neonates show variable clinical patterns during the antenatal and postnatal monitoring/screening periods. We conclude that aggressive and multidisciplinary approaches could achieve good clinical results in these patients.

Comparison of conservative therapy and steroid therapy for Bell's palsy in children / 소아과

PURPOSE: Bell's palsy is characterized by sudden onset of unilateral facial weakness. The use of corticosteroids for childhood Bell's palsy is controversial. This study aimed to identify clinical characteristics, etiology, and laboratory findings in childhood Bell's palsy, and to evaluate the efficacy of corticosteroid treatment. METHODS: We conducted a retrospective analysis of children under 19 years of age treated for Bell's palsy between January 2009 and June 2017, and followed up for over 1 month. Clinical characteristics, neuroimaging data, laboratory findings, treatments, and outcomes were reviewed. Patients with Bell's palsy were divided into groups with (group 1) and without (group 2) corticosteroid treatment. Differences in onset age, sex, laterality, infection and vaccination history, degree of facial nerve palsy, and prognosis after treatment between the groups were analyzed. RESULTS: One hundred patients were included. Mean age at presentation was 7.4±5.62 years. A total of 73 patients (73%) received corticosteroids with or without intravenous antiviral agents, and 27 (27%) received only supportive treatment. There was no significant difference in the severity, laboratory findings, or neuroimaging findings between the groups. Significant improvement was observed in 68 (93.2%) and 26 patients (96.3%) in groups 1 and 2, respectively; this rate was not significantly different between the groups (P=0.48). CONCLUSION: Childhood Bell's palsy showed good prognosis with or without corticosteroid treatment; there was no difference in prognosis between treated and untreated groups. Steroid therapy in childhood Bell's palsy may not significantly improve outcomes.

1q21.1 microdeletion identified by chromosomal microarray in a newborn with upper airway obstruction

A 1q21.1 microdeletion is an extremely rare chromosomal abnormality that results in phenotypic diversity and incomplete penetrance. Patients with a 1q21.1 microdeletion exhibit neurological-psychiatric problems, microcephaly, epilepsy, facial dysmorphism, cataract, and thrombocytopenia absent radius syndrome. We reported a neonate with confirmed intrauterine growth restriction (IUGR), micrognathia, glossoptosis, upper airway obstruction, facial dysmorphism, and eye abnormality at birth as well as developmental delay at the age of 1 year. These clinical manifestations, except for the IUGR and upper airway obstruction, in the neonate indicated a 1q21.1 microdeletion. Here, we report a rare case of a 1q21.1 microdeletion obtained via paternal inheritance in a newborn with upper airway obstruction caused by glossoptosis and tracheal stenosis.

Transient Abnormalities on Magnetic Resonance Imaging after Absence Seizures / 대한소아신경학회지

Magnetic resonance imaging (MRI) is recommended for patients with epileptic seizures to rule out an underlying focal lesion. However, abnormalities in idiopathic generalized epilepsy, including childhood absence epilepsy, cannot usually be identified using brain imaging modalities such as MRI. Peri-ictal MRI abnormalities have been most commonly reported secondary to status epilepticus and are rarely observed in patients with focal seizures and generalized tonic-clonic seizures. Transient peri-ictal MRI abnormalities in absence epilepsy are extremely rare. A five-year-old girl presented with a three-day history of absence seizures that persisted despite continued treatment with sodium valproate. Electroencephalography showed bursts of generalized 3-Hz spike-and-wave discharges, during and after hyperventilation. Abnormal cortex thickening in the left perisylvian region was detected on T2-weighted brain MRI, and cortical dysplasia or a tumor was suspected. The patient started treatment with lamotrigine and was seizure-free after one month. The abnormal MRI lesion was completely resolved at the two-month follow-up. We report on a patient with childhood absence epilepsy and reversible brain MRI abnormalities in the perisylvian region. To our knowledge, this is the first report of transient MRI abnormalities after absence seizures. Transient peri-ictal MRI abnormalities should be considered for differential diagnosis in patients with absence seizures and a focal abnormality on brain MRI.

Endovascular stenting of tracheoinnominate fistula after tracheostomy in a 14-year-old boy / 소아과

Tracheoinnominate artery fistula is a rare, fatal complication of tracheostomy, and prompt diagnosis and management are imperative. We report the case of tracheoinnominate artery fistula after tracheostomy in a 14-year-old boy with a history of severe periventricular leukomalacia, hydrocephalus, cerebral palsy, and epilepsy. The tracheoinnominate artery fistula was successfully treated with a stent graft insertion via the right common femoral artery. Endovascular repair of the tracheoinnominate artery fistula via stent grafting is a safe, effective, and minimally invasive treatment for patients in poor clinical conditions and is an alternative to traditional open surgical treatment.

Merosin-Deficient Congenital Muscular Dystrophy with Polymicrogyria and Subcortical Heterotopia: A Case Report

This paper reports the brain magnetic resonance imaging (MRI) findings of a case of merosin-deficient congenital muscular dystrophy (MDCMD) in a neonate and discusses the spectrum of brain involvement in MDCMD. A neonate presented hypotonia, increased serum creatine kinase levels, and polymicrogyria and subcortical heterotopia on brain MRI involving both posterior temporal and occipital lobes. Although these findings suggested Fukuyama muscular dystrophy, muscle biopsy showed dystrophic changes and an absence of merosin staining. We found that compound heterozygous mutation for c.2049_2050delAG (p.R683fs) and c.5866-2A>G in the LAMA2 gene which encodes Laminin-α2. To our knowledge, this is the second Korean case of MDCMD with polymicrogyria and subcortical heterotopias. This case shows that a range of brain structural malformations can be found in children with MDCMD and that the classification of congenital muscular dystrophy (CMD) is not complete yet, as indicated previously in reports suggesting other unclassified forms of CMD.

Poland Syndrome in One Dizygotic Twin: A Case Report / 대한주산의학회잡지

Poland syndrome, also known as pectoral aplasia-dysdactylia syndrome, is a rare anomaly, characterized by aplasia of the pectoralis major muscle with ipsilateral upper extremity anomalies. The cause of Poland syndrome is still unknown. Several twin patients were reported to propose a genetic or nongenetic hypothesis. We experienced a female baby showing absence of the pectoralis major muscle in a pair of mixed twin. The patient was referred to our hospital for evaluation of an asymmetric chest wall. She showed depression of the left chest wall, ipsilateral nipple hypoplasia, and axillary webbing. A chest CT scan showed aplasia of the left large pectoral muscle. Our patient had no abnormalities such as symbrachydactyly in an ipsilateral upper extremity. In comparison, a physical examination showed that the fraternal twin boy was completely normal.

Clinical Characteristics of Meconium Aspiration Syndrome according to Ventilator Care / 대한주산의학회잡지

PURPOSE: Meconium aspiration syndrome is an important cause of neonatal morbidity and mortality, and sometimes patients need mechanical ventilator therapy. The aim of this study was to identify the risk factors which required mechanical ventilation. METHODS: We retrospectively analyzed 44 infants diagnosed as meconium aspiration syndrome from January 2009 to December 2013. We divided into 2 groups (ventilator group and oxygen therapy group) and analyzed the clinical characteristics, vital signs, laboratory findings and clinical courses. RESULTS: Ventilator group and oxygen therapy group included each 22 infants, and there were no significant differences in clinical characteristics between two groups. Time to transfer and time to start oxygen therapy were longer in ventilator group but not statistical difference. Initial mean blood pressure and pH were significantly lower in ventilator group than in oxygen therapy group (P=0.026, P=0.003). Ventilator group had longer treatment period and worse prognosis than oxygen therapy group. CONCLUSION: If the infants with meconium aspiration and respiratory distress represent low pH and hypotension, we have to pay close attention to early oxygen supplementation and proper treatment to prevent poor clinical course.

A Study on Clinical Manifestations of Pulmonary Tuberculosis and Tuberculosis Contact Investigation in School-Age Children and Adolescents at Two Centers / 소아감염

PURPOSE: The aim of this study was to evaluate the clinical manifestations, contact history, and status of tuberculosis contact investigations in school-age children and adolescents with pulmonary tuberculosis (TB) at two centers. METHODS: This study was conducted with 54 patients in the age ranging from 10 to 18 years, who were diagnosed with pulmonary TB at the Pusan National University Hospital and Pusan National University Children's Hospital, January 2008 to December 2012. We retrospectively reviewed the medical records of the patients. RESULTS: The median age of the patients was 16 years old; 11 patients were aged 10 to 14 and 43 patients were aged 15 to 18. Among 54 patients, 19 had history of contact with pulmonary TB, 10 had contact with house members (household), and remaining 9 had contact with classmates (non-household). One out of 10 patients who had household contacts and 6 out of 9 patients who had non-household contacts were evaluated with contact investigation after the exposure to pulmonary TB. Among 7 patients who were evaluated with contact investigation, 3 were diagnosed with active pulmonary TB, 1 had latent tuberculosis infection (LTBI), and 3 had no evidence of TB or LTBI. The median period of diagnosis after the exposure to active pulmonary TB was 2 years in patients with household contacts and 0.23 years in patients with non-household contacts. CONCLUSION: This study suggested that if the contact investigation conducted properly, it would be helpful for early diagnosis and prevention of pulmonary TB.

Cause and incidence of eosinophilia in children: a single center study in one year

PURPOSE: Eosinophilia may be associated with various primary and reactive conditions. However, studies on the cause and incidence of eosinophilia in Korean children are rare. This study aimed to evaluate the cause and incidence of eosinophilia in patients at a single university hospital. METHODS: We studied 8,285 pediatric patients under the age of 18 years who had eosinophilia at Pusan National University Hospital. Premature and newborn infants were excluded. Eosinophilia was defined as an absolute eosinophil count greater than 450/microL. Eosinophilia was categorized as mild (450-1,500/microL), moderate (1,500-5,000/microL), and severe (>5,000/microL). The underlying conditions of eosinophilia were retrospectively investigated. RESULTS: Of 8,285 patients who had a hematology profile, 497 (5.9%) were found to have eosinophilia. Of patients with eosinophilia, 333 patients (67.0%) had identifiable and possible causes. The major causes of eosinophilia were allergic diseases (61.3%), infectious diseases (19.8%), immunologic diseases (9.0%) and hemato-oncologic disease (5.1%). Immunological disease such as Idiopathic hypereosinophilic syndrome, drug induced hypersensitivity syndrome and Graft-versus-host disease was the common condition with moderate to severe eosinophilia in which eosinophil count in peripheral blood was more than 1,500/microL. CONCLUSION: The most common cause of eosinophilia was allergic disease. Immunological disease was the common condition with moderate to severe eosinophilia.