Eczema, asthma, and allergic rhinitis are all atopic diseases, meaning they're caused by an exaggerated and inappropriate immune response to a perceived threat. Essentially, your body's immune system recognizes a harmless substance (an antigen) as an enemy and launches a counterattack, leading to inflammation.
• Eczema: skin inflammation caused by dysregulation of the skin's barrier function
• Asthma: bronchoconstriction caused by hyperresponsive airways
• Allergic rhinitis (AR): nasal inflammation caused by sensitization to aeroallergens
These 3 conditions are often linked across the lifespan, with childhood eczema sometimes leading to allergic rhinitis and asthma in a process called the atopic march.
• Up to 80% of children with asthma are later diagnosed with asthma and/or allergic rhinitis
• Up to 40% of people with allergic rhinitis also have asthma
• Up to 50% of people with asthma also have allergic rhinitis
There's no clear consensus on what causes these atopic diseases, though experts know that our environment is at least partially responsible. Factors like diet, hygiene, infections, and air pollution have all been implicated in the atopic triad.