The rationale was the omega 3 and 6 fatty acids contained in it have an anti-inflammatory effect, which they do, providing you take a big enough dose. Evening primrose oil was actually on the National Health Service in Britain for infant eczema for a while, but it fell into disrepute after it bombed out in several clinical trials in the early 1990s. It’s understandable that mothers would want to test it, but the dose is 2-4g daily for little ones (6-8g daily for adults), which can be a challenge to get into a little baby.
Dr Geraldine Moses, of the Pharmaceutical Society of Australia, says that evening primrose oil was very popular for infant eczema in the 1980s.   However, Moses reports the side-effects she’d want parents to be aware of would be:
1)A blood thinning effect.
2)Decreasing the seizure threshold. (Epileptics have had seizures on evening primrose oil).
Eczema can be genetic and there’s often the “trilogy” with hayfever-rhinitis and asthma in individuals. Winter skin dryness tends to make eczema worse and clothing rubbing continuously can aggravate eczema as well.
Avoid synthetic fabrics and dress him in cotton and natural fibres. The key is to moisturise the skin, discourage him from scratching and to avoid long, soaking baths. Ensure his fingernails are kept short. You may want to put mittens on his hands if he’s scratching in his sleep. Many kids outgrow eczema though there is no consensus on when this happens, with ages varying from lower primary to adolescence.