Eczema and Food Allergy: Understanding the Connection

The atopic march — eczema as the starting point

Eczema is often the first manifestation of the 'atopic march' — the tendency for allergic conditions to develop in sequence. Many children with eczema go on to develop food allergy, hay fever, and asthma. Eczema is not just a skin condition; it is a systemic immune condition that reflects an underlying allergic predisposition. The skin barrier dysfunction that causes eczema also allows allergens to penetrate the skin and sensitise the immune system.

How eczema leads to food allergy

Research has shown that sensitisation to food allergens — particularly peanut and egg — can occur through the skin in children with eczema, before the food is ever eaten. This 'epicutaneous sensitisation' explains why children with eczema have a significantly higher risk of developing food allergy. It also explains why early introduction of allergenic foods (particularly peanut) in infants with eczema can actually reduce the risk of developing allergy — a finding from the landmark LEAP trial.

Does food allergy cause eczema?

In some children — particularly infants — food allergens actively drive eczema flares. Around 30–40% of infants with moderate-to-severe eczema have an underlying food allergy (most commonly cow's milk or egg) that is contributing to their skin condition. Identifying and eliminating the trigger food can lead to significant improvement in eczema control. However, food allergy is not the cause of eczema in all children — in older children and adults, environmental allergens (house dust mite, pet dander) are more commonly involved.

When should food allergy testing be considered in eczema?

• Moderate-to-severe eczema in infants under 2 years that is not responding to standard treatment
• Eczema that flares consistently after eating specific foods
• Eczema in a baby who has not yet been introduced to allergenic foods
• Eczema alongside other allergic symptoms (vomiting, hives, wheeze) after eating
• Family history of food allergy alongside difficult-to-control eczema

The risk of unnecessary dietary elimination

It is important not to eliminate foods from a child's diet without specialist assessment and allergy testing. Unnecessary elimination can lead to nutritional deficiencies (particularly calcium and protein in dairy-free diets), affect growth, and may actually increase the risk of developing a more severe allergy when the food is reintroduced. Elimination should only be undertaken after specialist assessment, with dietitian support.

Environmental allergens and eczema

In older children with eczema, environmental allergens — particularly house dust mite — are a more common trigger than food. Allergy testing can identify sensitisation to house dust mite, pet dander, and pollen. Targeted avoidance measures and, in some cases, allergen immunotherapy can help reduce eczema flares driven by environmental allergens.

A joined-up approach to eczema and allergy

Optimal management of eczema with suspected allergic triggers requires a joined-up approach. Dr Anandarajan works closely with specialist dietitians and dermatologists to provide comprehensive care — from allergy testing and trigger identification through to dietary management, skin barrier therapy, and, where appropriate, allergen immunotherapy.