Atopic dermatitis (AD), also known as atopic eczema or eczema, is the most common skin disease, characterized by a disturbance of epidermal barrier function culminating in dry skin, itching lesions, IgE-mediated sensitization to food and allergens, chronic relapsing skin inflammation, and a frequent need of long-term treatment. The disease affects up to 25% of children and up to 3% of the adult population, where prevalence has increased 2–3 fold during the last century, particularly in industrialized countries. The 2014 U.S. census estimated that 19,876,883 children were between the ages of 0-5, where 90% of all cases of AD begin. Most patients develop AD during infancy or early childhood, but late-onset AD can occur at all ages—the course of disease being heterogenous and unpredictable as some patients develop persisting or chronic relapsing AD, whereas others lose nearly all symptoms until adolescence. AD is often the initial step in the atopic march, which leads to asthma and allergic rhinitis in the majority of afflicted patients. Other complications include frequently occurring bacterial or viral superinfections that lead to the need of systemic antibacterial or antiviral treatment and hospitalization in severe cases. Consequently, there exists a significant impact on quality of life for patients and their families, as patients suffer from social stigmatization, sleep disorders mainly caused by the massive itch, and a higher risk of depression, at an economic cost in the billions.
Psoriasis is a chronic immune-mediated inflammatory skin disorder presenting clinically as well-demarcated, raised, erythematous, scaly plaques predominantly affecting the scalp, trunk, and extensor surfaces, tending to have a chronic relapsing and remitting course. Plaque-type psoriasis is the most common form occurring in 85%—95% of affected patients with severity ranging from a few scattered plaques to involvement of almost the entire body surface. The disease affects 1 - 2% of the population worldwide and its mild-to-moderate condition affects approximately 80% of that total population, beginning in childhood for almost 1/3 of all cases. Psoriasis in children and adolescents in particular can have a profound long-term impact on their quality of life, with associated comorbidities such as obesity, hypertension, diabetes mellitus, rheumatoid arthritis, Crohn’s disease, and psychiatric disorders, making early diagnosis and management essential. Current treatments are intended for adult patients and are limited in safety and efficacy; most systemic treatments are not approved for use in children and are being used off-label.