Asthma

Asthma is chronic inflammation and narrowing of the airways, felt as wheeze, cough and breathlessness. It forms the classic atopic triad with Atopic Dermatitis and Allergic Rhinitis, and shares the Th2 Immune Response with eczema. For parents of a toddler with eczema, the key question is “will my child get asthma too?” The link is real and dose-dependent. About 20% of children with mild AD have asthma, compared with over 60% of those with severe AD (Medicina 2024). Cohorts consistently show raised odds after early eczema. In the Swedish DBH study the OR was 3.07 for allergic asthma. In Canadian CHILD the relative risk was 2.23 at age 3. In PASTURE the aOR was 2.87 by age 6 for early, persistent AD.

Atopic Dermatitis [relates] Asthma Th2 Immune Response [part-of] Asthma

Which eczema carries the risk. The risk is concentrated in severe and persistent disease. In Paternoster’s analysis of ALSPAC and PIAMA (Eczema Trajectories), the early-onset-persistent eczema class had the strongest links to asthma at ages 7, 11 and 13, along with Filaggrin mutations and parental atopy. The common early-onset-early-resolving class was only weakly linked to asthma. A mid-onset eczema class (peaking around age 6) was strongly linked to asthma without any FLG link. In Swedish BAMSE, 17.2% of children with persistent infantile eczema had asthma at 12. In the German Multicenter Allergy Study (Illi 2004), early AD without early wheeze or allergic sensitisation carried no extra risk of wheeze at school age (aOR 1.11). In many asthmatic children, wheeze started before or alongside the eczema. The authors called AD-plus-wheeze “a distinct phenotype rather than a progressive development from AD to asthma.”

Eczema Trajectories [relates] Asthma Filaggrin [worsens] Asthma

Conflict: [Classic atopic-march model, CHILD/PASTURE/DBH cohorts cited in Medicina 2024] says early AD raises later asthma risk as a step in a progression. [Illi et al., JACI 2004; Paternoster et al., JACI 2018; Belgrave et al., PLoS Med 2014] say the association reflects shared phenotypes (co-occurring wheeze, sensitisation, genetics) rather than a sequence; only ~7% of symptomatic children follow a march pattern. Unresolved — add to open_questions.

Treatment and asthma. Some parents fear that steroid creams “push eczema inward” and cause asthma. “Inducing asthma” is a recognised Steroid Phobia belief in the TOPICOP scale (Moret 2013), and the TOPICOP authors note such beliefs are often not based on scientific findings. None of the cohorts in this vault links Topical Corticosteroids to asthma onset. What predicts asthma is the eczema’s severity and persistence, early wheeze and sensitisation. Equally, no trial has shown that treating toddler eczema well prevents asthma (Medicina 2024; see Atopic March and Eczema Prognosis). House-dust-mite avoidance has not proven useful for asthma prevention either. One practical home hazard is chlorine fumes from Bleach Baths in a poorly ventilated bathroom.

Steroid Phobia [contradicts] Topical Corticosteroids Eczema Prognosis [relates] Asthma

Connections

• Atopic Dermatitis — later comorbidity, source: Medicina 2024
• Bleach Baths — bleach fumes in a poorly ventilated bathroom may trigger flares, source: Northwestern Now 2017
• Atopic March — classic third step; ~20% of mild vs >60% of severe AD develop asthma, source: Medicina 2024
• Eczema Prognosis — asthma risk tracks eczema severity/persistence, source: Illi 2004; Paternoster 2018
• Eczema Trajectories — strongest with early-onset-persistent and mid-onset AD classes, source: Paternoster 2018
• Multicenter Allergy Study — early AD without wheeze/sensitisation: no extra asthma risk (aOR 1.11), source: Illi 2004
• BAMSE — 17.2% asthma at 12 after persistent infantile eczema, source: Ballardini 2014
• Steroid Phobia — ‘TCS induce asthma’ is a recognised unfounded belief, source: Moret 2013
• Filaggrin — FLG mutations linked to persistent AD with asthma comorbidity, source: Paternoster 2018
• Allergic Rhinitis — 74–81% of asthmatic children also have rhinitis, source: Medicina 2024