Implications for practice  

Oral borage oil and evening primrose oil lack effect on eczema; improvement was similar to respective placebos used in trials. Oral BO and EPO are not effective treatments for eczema.
In these studies, along with the placebos, EPO and BO have the same, fairly common, mild, transient adverse effects, which are mainly gastrointestinal.
The short-term studies included here do not examine possible adverse effects of long-term use of EPO or BO. A case report warned that if EPO is taken for a prolonged period of time (more than one year), there is a potential risk of inflammation, thrombosis, and immunosuppression; another study found that EPO may increase bleeding for people on Coumadin® (warfarin) medication.

Implications for research 

Noting that the confidence intervals between active and placebo treatment are narrow, to exclude the possibility of any clinically useful difference, we concluded that further studies on EPO or BO for eczema would be hard to justify.
This review does not provide information about long-term use of these products.
The effect of gamma-linolenic acid on clinical status, red cell fatty acid composition and membrane microviscosity in infants with atopic dermatitis.
A double blind placebo-controlled study of two doses of gamma-linolenic acid, provided by evening primrose oil (EPO, Epogam, Searle, U.K.), in children with atopic dermatitis was performed: 1) to examine the effect of gamma-linolenic acid administration on the clinical status of children with atopic dermatitis and abnormalities of IgE-mediated immune responses compared to those without such IgE abnormalities; 2) to investigate the effect of gamma-linolenic acid on red cell fatty acid composition and 3) to assess whether treatment with gamma-linolenic acid induced changes in red cell membrane microviscosity. A significant improvement in the overall severity of the clinical condition was seen in children treated with gamma-linolenic acid, independent of whether the children had manifestations of IgE-mediated allergy. Furthermore, gamma-linolenic acid treatment increased the percentage content of n-6 fatty acids in erythrocyte cell membrane; this increase was more marked in the membranes of children treated with high doses of EPO. In the high dose group a significant increase in dihomogamma-linolenic acid (DGLA) occurred. This may be of particular relevance because of the potential importance of DGLA as a precursor of antiinflammatory prostanoids. Red cell membrane microviscosity did not change in any group after treatment with EPO, even in high doses, despite a significant increase in the proportion of long chain polyunsaturated fatty acids.