Atopic Dermatitis (Eczema): Causes, Types, Diagnosis and Evidence-Based Treatment

• Atopic dermatitis is a chronic, relapsing inflammatory skin condition caused by a combination of a leaky skin barrier and an over-reactive immune system. It is not an infection, not caused by "dirty blood," and not something a child simply grows out of on schedule.
• It affects up to one in five children and roughly 2–10% of adults worldwide. Hong Kong estimates vary considerably depending on how the diagnosis is defined, and local prevalence has risen steadily over two decades.
• Around 60% of cases begin in the first year of life, but adult-onset atopic dermatitis is real and increasingly recognised.
• Severity is not the whole picture. Sleep loss, concentration, mood and school or work performance are frequently affected more than the visible rash.
• Treatment is now genuinely effective. The modern approach is daily barrier repair, prompt treatment of flares, proactive maintenance to prevent the next flare, and targeted systemic therapy for those who need it — including several biologics and oral JAK inhibitors approved in the last few years.
• Undertreatment caused by fear of topical steroids is one of the most common reasons eczema stays out of control. Used correctly, they are safe.
• Most children improve substantially by adolescence, but the underlying tendency to dry, sensitive skin usually persists. Control, not cure, is the realistic goal — and good control is achievable for most people.