Interactions Between Atopic Dermatitis and Staphylococcus aureus Infection: Clinical Implications

Staphylococcus aureus commonly colonizes the skin of atopic dermatitis (AD) patients and contributes to the development and exacerbation of AD. Multiple factors are associated with colonization of AD skin by S. aureus, including the strength of S. aureus-corneocyte adhesion, deficiency of antimicrobial peptides, decreased levels of filaggrin and filaggrin degradation products, overexpressed Th2/Th17 cytokines, microbial dysbiosis and altered lipid profiles. S. aureus colonization on AD skin causes skin barrier dysfunction through virulence factors such as superantigens (toxins), enzymes and other proteins. Furthermore, colonization of AD skin by S. aureus exacerbates AD and may contribute to microbial dysbiosis, allergen sensitization, Th2/Th17 polarization, development of atopic march and food allergy in AD patients. Skin colonization of S. aureus, particularly methicillin-resistant S. aureus (MRSA), is one of the major challenges commonly encountered in the management of AD. Bleach bath, and topical or systemic antibiotics could be used to control S. aureus infection on AD skin. However, careful use of antibiotics is required to control the occurence of MRSA. Recently, various strategies, including microbiome transplant, monoclonal antibodies against virulent toxins, vaccines and recombinant phage endolysin, have been studied to control S. aureus infection on AD skin. Further advances in our understanding of S. aureus could provide us with ways to manage S. aureus colonization more effectively in AD patients.

Significance of Skin Barrier Dysfunction in Atopic Dermatitis

The epidermis contains epithelial cells, immune cells, and microbes which provides a physical and functional barrier to the protection of human skin. It plays critical roles in preventing environmental allergen penetration into the human body and responsing to microbial pathogens. Atopic dermatitis (AD) is the most common, complex chronic inflammatory skin disease. Skin barrier dysfunction is the initial step in the development of AD. Multiple factors, including immune dysregulation, filaggrin mutations, deficiency of antimicrobial peptides, and skin dysbiosis contribute to skin barrier defects. In the initial phase of AD, treatment with moisturizers improves skin barrier function and prevents the development of AD. With the progression of AD, effective topical and systemic therapies are needed to reduce immune pathway activation and general inflammation. Targeted microbiome therapy is also being developed to correct skin dysbiosis associated with AD. Improved identification and characterization of AD phenotypes and endotypes are required to optimize the precision medicine approach to AD.

Epidermal Barrier in Atopic Dermatitis

Atopic dermatitis (AD) is a complex disease that affects up to 20% of children and impacts the quality of patients and families in a significant manner. New insights into the pathophysiology of AD point to an important role of structural abnormalities in the epidermis combined with immune dysregulation. Filaggrin (FLG) is synthesized as a large precursor, profilaggrin, and is expressed in the upper layers of the epidermis. FLG plays a critical role in the epidermal barrier, and FLG mutations cause abnormal epidermal function. FLG mutations are strongly associated with early-onset, and persistent severe AD. In addition, FLG deficiency in the epidermis is related to allergic sensitization and asthma. The basic skin care including repair and protection of the skin barrier with proper hydration and topical anti-inflammatory therapy is important to control the severity of skin disease in patients with AD.

Effects of Early and Low-Dose Ribavirin Therapy on Respiratory Syncytial Virus Bronchiolitis in Previously Healthy Infants / 소아알레르기및호흡기학회지

PURPOSE: we performed this study to determine whether early and low dose ribavirin therapy for respiratory syncytial virus (RSV) bronchiolitis in previously healthy infants may reduce the duration of hospital stay. METHODS: Thirty-four Previously healthy infants with RSV bronchiolitis were enrolled in this study. Early in the course of illness, less than 5 days, aerosol ribavirin was administered at a low, single-dose (3 g/150 mL/day) and then we assessed the duration of hospital stays for 16 infants treated with ribavirin (ribavirin group) and 18 infants who received conservative treatment (control group). RESULTS: The baseline characteristics of each group were not significantly different with respect to gestational age, birth weight, age, sex, weight, and height. On admission, there were no significant differences between the two groups in the respiratory rate and body temperature. Duration of hospitalization was significantly shorter in the ribavirin group (4.4+/-0.3 days) as compared to the control group (5.5+/-0.3 days) (P=0.02). CONCLUSION: Early and low-dose ribavirin therapy for RSV bronchiolitis in previously healthy infants may decrease duration of hospital stay.

Human Metapneumovirus Infection in Hospitalized Children with Acute Respiratory Disease in Korea

Human metapneumovirus (hMPV) is a recently isolated virus, mostly associated with acute lower respiratory infection in children, of which symptoms are similar to those of respiratory syncytial virus (RSV) infection. The aim of our study was to determine the frequency of hMPV in hospitalized children with acute respiratory tract disease in Korea. Nasal aspirates from hospitalized children with respiratory infections under 15 yr old between December 2003 and February 2005 were included in the study. Each sample was analyzed for RSV, adenovirus, influenza virus A and B, and parainfluenza virus by indirect fluorescent assay (IFA). F-gene sequences were used for PCR for the detection and sequencing of hMPV. In total 381 samples, negative samples in which any viral pathogen could not be identified by IFA were 231 cases. hMPV was detected using reverse transcriptase-PCR (RT-PCR) in 28 of 231 (12.1%) children who were not infected with another respiratory viruses. The hMPV-infected children were diagnosed as having pneumonia, bronchiolitis, bronchial asthma exacerbation, croup, and upper respiratory tract infection. Most of the RT-PCR positive samples for hMPV were collected in winter season. These results suggest that hMPV may be a responsible pathogen causing acute respiratory tract infection in Korean children.

Trace element concentrations profiles in the hair of normal children living in the northern area of Seoul / 소아과

PURPOSE: The reliability of hair mineral analyses regarding nutritional status, environmental exposure or diseases is controversial. The aim of this study was to determine the normal reference range of hair mineral concentration of Korean children. METHODS: We examined hair mineral concentrations of 223 children(3-12 yrs old, 110 boys, 113 girls, mean age 8.8+/-2.2 yrs old) living in the northern area of Seoul. The trace elements including six toxic elements(Al, As, Cd, Ba, Hg, Pb) and 11 nutritional elements(Na, Mg, P, K, Ca, Cr, Mn, Fe, Cu, Zn, Se) were analyzed by inductive coupled plasma mass spectrometry(ICP-MS). RESULTS: The mean concentrations of Ca and Mg were higher in girls than in boys. The mean concentrations of Cd, Pb and Cr were higher in boys than girls. The Zn, Ca, Mg, Cu and Hg levels in hair samples were positively correlated with increasing age. The Zn levels of the Korean children's hair samples appear to be lower than that of other countries' reference values. CONCLUSION: There are considerable differences in hair mineral concentrations by age, sex and race. Additional research is needed to establish Korean reference values, and to evaluate the usefulness of hair mineral analyses as a screening tool for nutrition- and environment-related childhood diseases.

A Comparison of Clinical Manifestations in Neonates and Infants Infected by Respiratory Syncytial Virus / 소아과

PURPOSE: This study was performed to evaluate of clinical manifestations of neonatal respiratory syncytial virus(RSV) infection, and to evaluate of differences of clinical manifestations between the neonates and infants who were infected by RSV. METHODS: We reviewed the medical record of 75 children who were younger than 12 months of age and infected by RSV. We classified then into a neonatal group(n=30) and an infantile group(n=45) and compared the neonatal group with the infantile group by clinical manifestation and chest X-ray. RESULTS: Fever was more significant in the infantile group than the neonatal group(P=0.0256). The chest wall retraction was seen significantly in the neonatal group(P=0.0034). The study didn't show a significant difference in wheezing or rale between the two groups. There was not any significant difference in cyanosis and apnea between the two groups but the symptoms appeared more frequently in the neonatal group. With regard to chest X-rays, pneumonia is seen more frequently in the neonatal group(23/30, 76.67%) and bronchiolitis is seen more frequently in the infantile group (25/45, 55.55%). CONCLUSION: Neonatal RSV infections appear with fever less than infantile RSV infection and may appear with mild clinical manifestations, but chest retraction and pneumonia are more frequently present than in the infantile group. Therefores, neonate needs careful observation and treatment.