Giới thiệu
Atopic Dermatitis Pediatric_Disease Background
Atopic dermatitis is a familial, chronic relapsing inflammatory skin disease characterized by intense itching and dry skin, with inflammation and exudation that commonly presents during early infancy and childhood but can persist or start in adulthood. This is also referred to as “atopic eczema."
Dịch tễ học
Atopic dermatitis is one of the most common skin diseases afflicting both adults and children. In 2021, there were approximately 72.4 million pediatric cases of atopic dermatitis worldwide. The prevalence varied by region, with the highest rates in Central Asia, high-income Asia-Pacific, and Western Europe, and the lowest in Sub-Saharan Africa.
Most children develop atopic dermatitis within the first year of life, and nearly all are affected by 5 years of age. The infant’s skin has a developing epidermal barrier and would only fully mature at least at the first year of age; thus, their skin absorbs more water and loses excess water faster than adult skin. This skin characteristic makes them susceptible to irritation and infections. The highest prevalence was observed among children aged 5–9 years. Atopic dermatitis is more common in females than in males.
Nguyên nhân
The cause of atopic dermatitis involves heredity and is seen in 80% in monozygous twins and 20% in heterozygous twins. Other common causes include allergens such as food, soaps, detergents, inhalant allergens, and skin infections.
Sinh lý bệnh
Atopic dermatitis arises from a complex interaction of genetic predisposition, immune dysregulation, barrier impairment, environmental triggers, and microbial imbalance. Mutations in genes such as filaggrin (FLG), FLG2, CLDN1, and SPINK5 weaken the epidermal barrier and promote itch, while the globally defective epithelium in atopic dermatitis allows easier penetration of environmental irritants, allergens, and microbes. Variants in immune-related genes, including interleukin (IL)-4, IL-13, IL-31, and thymic stromal lymphopoietin (TSLP), can drive abnormal inflammatory responses that further aggravate barrier dysfunction. There is also an increased IgE production and a lack of skin barrier, producing dry skin due to abnormalities in lipid metabolism and protein formation.
Yếu tố nguy cơ
The risk factors of atopic dermatitis include environmental toxins (eg cigarette smoke, pollutants, allergens, and microbial agents) that penetrate a compromised skin barrier that can trigger a T-helper (Th2)-skewed immune response that plays a central role in the development of atopic dermatitis. There is also susceptibility to infections caused by Staphylococcus aureus/epidermidis and Malassezia furfur through abnormal microbial colonization. The decreased diversity of the cutaneous microbiome secondary to S aureus colonization is significantly associated with atopic dermatitis flare-up.