Peanut allergy is one of the most serious food allergies and is closely linked to eczema. Infants with eczema are 11 times more likely to develop peanut allergy than those without it. The leading theory is that peanut proteins settling on broken eczema skin sensitise the immune system through the skin, while eating peanuts early actually promotes tolerance — making the skin the danger route and the mouth the protective route.

Current guidelines recommend early peanut introduction for high-risk infants with eczema. Reactions can be triggered by very small amounts — even traces from shared cooking surfaces — and can be severe, including anaphylaxis. An important preparation note: dry-roasting peanuts (the standard Western method) makes them about 90 times more allergenic than boiling, which may explain why peanut allergy is common in Western countries but rare in regions where peanuts are typically boiled or fried.