Pollen

Tree and grass pollen are outdoor aeroallergens that can irritate or inflame eczema-prone skin. Reactions usually appear in spring and summer on exposed sites such as the face, arms and legs (Allergy UK). The NHS lists pollen among allergens that make eczema worse. NICE CG57 advises considering inhalant allergy in children whose eczema flares seasonally, in those with Asthma or Allergic Rhinitis, and in children aged 3 or over with eczema on the face, especially around the eyes. A weakened skin barrier may let pollen proteins sensitise the skin directly and trigger rapid eczematous reactions where they settle (Nishie 2012).

Pollen [triggers] Atopic Dermatitis Pollen [part-of] Environmental Triggers Skin Barrier Dysfunction [relates] Pollen

Who flares in pollen season. In a Dutch study of 110 children with difficult-to-treat eczema, 36% reported flares in the pollen season. These children were far more often sensitised to pollen (73% vs 28%), especially tree and grass. Hay fever (OR 42), dark skin type (OR 5.1) and younger age best predicted pollen-season flares (Bosma et al. 2021; see Eczema in Skin of Colour). The authors concluded that history alone identifies this group, so testing is not needed for that purpose. A Japanese diary study found that eczema symptoms rose and fell with actual daily cedar/cypress pollen counts (Nishie 2012).

Allergic Rhinitis [relates] Pollen Pollen [relates] Eczema in Skin of Colour

Conflict: [Bosma et al., J Dermatol 2021] found pollen-season flares strongly associated with hay fever (OR 42) and pollen sensitisation. [Nishie et al., ISRN Allergy 2012] found the frequency of pollen-season flares did not depend on IgE levels or seasonal allergic rhinitis. Unresolved — add to open_questions.

Sensitisation in toddlers. Pollen sensitisation needs repeated seasons of exposure, so it is uncommon in infants and rises through the toddler years. Indoor allergens such as House Dust Mites and pets are more common early on. In Boston data, outdoor pollen sensitisation was 9.5% at 0–2 years and 18.2% at 2–4 years. Among 361 children under 4 who had skin prick tests, 13% were sensitised to tree pollen (Sedaghat et al. 2014). Some clinicians therefore defer outdoor-allergen testing in very young children (Sedaghat 2014). Eczema in the first 2 years is a risk factor for later hay fever and asthma, and children with eczema are more often sensitised to aeroallergens than other children (Bosma 2021, citing cohort data; see Atopic March). A positive skin prick or specific IgE result shows sensitisation, not proof that pollen drives a given flare.

Atopic March [relates] Pollen Skin Prick Testing [relates] Pollen

Practical measures. On high-pollen days, avoid drying clothes and bedding outdoors. Put a barrier such as clothing, a mat or a rug between the child and grass when sitting outside (Allergy UK). Wash the face and hands after outdoor play and moisturise (Emollient Therapy). Pets can carry pollen in their coats (Pets and Eczema). If seasonal flares are suspected, NICE CG57 supports assessing for inhalant allergy. Any co-existing hay fever should be managed alongside the eczema.

Emollient Therapy [relates] Pollen

Connections

• Environmental Triggers — seasonal aeroallergen, source: Allergy UK; NICE CG57
• Pets and Eczema — pollen carried on pet coats, source: National Eczema Society
• Allergic Rhinitis — hay fever strongest predictor of pollen-season flares, source: Bosma 2021
• NICE CG57 — consider inhalant allergy with seasonal flares, source: NICE CG57
• Heat and Sweat — overlapping summer flare factors, source: Bosma 2021
• Atopic March — eczema precedes aeroallergen sensitisation, source: Bosma 2021