Genetic link

Allergy runs in families and is especially common in children born to allergic mothers. Maternal antibodies are passed on to an infant in the womb where the unborn infant becomes sensitised. Research shows that this can happen as early as 23 weeks into pregnancy. A 1994 study on 4,000 children in Aberdeen showed that 32% of children born to a mother with asthma went on to develop asthma, whereas only 20% of children whose father had asthma developed the condition.

The ‘allergic march’ usually begins with asthma in infancy and is soon followed by eczema, but it can be the other way round; eczema first, followed in quick succession by asthma. From then there is often an onwards march to food allergy, so that within a few months all three allergies are established.