Childhood Eczema and Environmental Triggers: Smoke, Vape & Household Irritants

Eczema (atopic dermatitis) is the most common inflammatory skin condition in children. It causes itchy, painful skin lesions and frequent infections, often disrupting sleep for both children and their families long beyond infancy. In severe cases, eczema can significantly impact a child’s quality of life and development.

Genetics and Environment: A Two-Part Story

Eczema has a strong genetic component. One key factor is a deficiency in filaggrin, a protein essential for maintaining the skin barrier. When filaggrin is lacking, the skin becomes more vulnerable to dryness and irritation and allows allergens and irritants to penetrate more easily (1,2).

However, not every child with this genetic predisposition develops eczema, highlighting the important role of environmental exposures.

How Environmental Exposures Influence Eczema

Children do not need to directly inhale irritants for them to have an effect. Residue on clothing, hair, or skin—known as third‑hand exposure—can also contribute to symptoms.

1. Contact With Irritants

Common irritants include:

• Cigarette smoke or vape residue
• Air pollution
• Household chemicals and fragrances
• Dust mites, pets, and pollen

2. Skin Barrier Breakdown

Environmental irritants can damage the skin barrier, increasing transepidermal water loss and allowing penetration of allergens, microbes, and irritants (2).

3. Immune System Overreaction

The penetration of irritants can trigger immune dysregulation, causing inflammation and hypersensitivity responses typical of eczema (3).

4. Clinical Eczema

This results in:

• Itching
• Redness
• Dry, rough skin
• Recurrent flare‑ups 

Common Environmental Triggers

Cigarette Smoke

Cigarette smoke contains thousands of chemicals known to disrupt immune function and the skin barrier.

• A meta‑analysis of 86 studies found that passive smoke exposure is associated with increased eczema prevalence (6).
• Maternal smoking during pregnancy was not consistently associated with eczema risk (6).
• Infants exposed to smoke show higher food‑specific IgE levels and increased eczema prevalence in early life (7).

Vape Residue

Although often marketed as safer than tobacco, vaping is not harmless.

• E‑cigarette aerosol can induce oxidative stress in keratinocytes (8).
• A 2024 study of over 35,000 households found children exposed to parental vaping had a 24% higher likelihood of eczema (8). 

Other common triggers:

• Dust mites: Up to one third of sensitised individuals report worsening eczema symptoms with exposure (4).
• Pets: Animal dander can act as an irritant and contribute to allergen exposure (3).
• Pollens: Airborne allergens can trigger immune responses and eczema flares (3).
• Mould: Fungal spores can irritate the skin and immune system (3).
• Food allergies: Approximately 30–50% of children with eczema have a food allergy (5).

Conclusion

Childhood eczema arises from a combination of genetic vulnerability and environmental exposure. Filaggrin deficiency weakens the skin barrier, but environmental triggers often determine disease onset and severity.

Exposures such as dust mites, pet dander, pollen, mould, household chemicals, smoke or vaping residue can disrupt the skin barrier and activate immune responses.

Understanding these pathways allows families to:

• Reduce exposure to irritants
• Be mindful of residue on clothing and skin
• Support the skin barrier through good skincare practices

While genetics cannot be changed, environmental factors can be modified. Reducing these exposures can help break the cycle of inflammation and improve outcomes for children with eczema.