Key message: Oral evening primrose oil and borage oil are not effective treatments for eczema

Anyone who suffers from eczema, or is close to someone who has it, knows that this common skin condition can be a real misery. In the developed world it’s on the increase. Treatments can be very time-consuming and many people struggle to find effective relief from the itching and help for sore, weeping, cracked or bleeding skin. Some people use complementary therapies, including evening primrose oil (EPO) and borage oil (BO) taken by mouth, but to date it has been unclear whether these are effective and safe.

Back in 2003, the Cochrane Skin Group‘s Co-ordinating Editor Hywel Williams, who is Professor of Dermato-Epidemiology at the University of Nottingham, wrote in the BMJ that it was time to say goodnight to evening primrose oil for eczema. I would urge you to read this short article, freely available from the link below, which tells the chequered history of the development of EPO, which has been “marred by lack of data in the public domain”. Clearly this is still a problem, as it is in all areas of medicine; if you aren’t aware of the All Trials campaign then please click here to find out why we need to demand that all trialsClinical trials are research studies involving people who use healthcare services. They often compare a new or different treatment with the best treatment currently available. This is to test whether the new or different treatment is safe, effective and any better than what is currently used. No matter how promising a new treatment may appear during tests in a laboratory, it must go through clinical trials before its benefits and risks can really be known. are registered and all results reported and what you can do to help.

The Cochrane Skin Group has just published a new review which brings together evidence from 27 randomizedRandomization is the process of randomly dividing into groups the people taking part in a trial. One group (the intervention group) will be given the intervention being tested (for example a drug, surgery, or exercise) and compared with a group which does not receive the intervention (the control group).   trialsClinical trials are research studies involving people who use healthcare services. They often compare a new or different treatment with the best treatment currently available. This is to test whether the new or different treatment is safe, effective and any better than what is currently used. No matter how promising a new treatment may appear during tests in a laboratory, it must go through clinical trials before its benefits and risks can really be known. involving almost 1600 children and adults with eczema; 11 studies were unpublished drug company studies. 19 assessed EPO and 8 BO. Participants took EPO or BO or a placeboAn intervention that appears to be the same as that which is being assessed but does not have the active component. For example, a placebo could be a tablet made of sugar, compared with a tablet containing a medicine. (a ‘dummy’ oil such as olive oil) for between 3 and 24 weeks.

What did they find?

• EPO and BO were no better than placeboAn intervention that appears to be the same as that which is being assessed but does not have the active component. For example, a placebo could be a tablet made of sugar, compared with a tablet containing a medicine. oils in improving eczema symptoms
• Mild side effects, such as stomach upsets, were experienced in both treatmentSomething done with the aim of improving health or relieving suffering. For example, medicines, surgery, psychological and physical therapies, diet and exercise changes. and placeboAn intervention that appears to be the same as that which is being assessed but does not have the active component. For example, a placebo could be a tablet made of sugar, compared with a tablet containing a medicine. groups, with no difference between them

How good was the evidence and what are the gaps?

• The evidence was pretty good quality in that most of the studies were judged to be at low riskA way of expressing the chance of an event taking place, expressed as the number of events divided by the total number of observations or people. It can be stated as ‘the chance of falling were one in four’ (1/4 = 25%). This measure is good no matter the incidence of events i.e. common or infrequent. of biasAny factor, recognised or not, that distorts the findings of a study. For example, reporting bias is a type of bias that occurs when researchers, or others (e.g. drug companies) choose not report or publish the results of a study, or do not provide full information about a study.
• Studies consistently showed no benefit of EPO or BO over placeboAn intervention that appears to be the same as that which is being assessed but does not have the active component. For example, a placebo could be a tablet made of sugar, compared with a tablet containing a medicine. oils
• Differences between the studies and the ways in which results were reported limited the extent to which results could be combined. The results from 8 EPO studies could be combined in a meta-analysisThe use of statistical techniques in a systematic review to combine the results of included studies. Sometimes misused as a synonym for systematic reviews, where the review includes a meta-analysis.  
• Missing dataData is the information collected through research. was a problem and attempts to get this missing dataData is the information collected through research. were unsuccessful
• TrialsClinical trials are research studies involving people who use healthcare services. They often compare a new or different treatment with the best treatment currently available. This is to test whether the new or different treatment is safe, effective and any better than what is currently used. No matter how promising a new treatment may appear during tests in a laboratory, it must go through clinical trials before its benefits and risks can really be known. were small; in some as few as 12 people took part and the largest involved only 160
• Only two studies of EPO measured improvement in quality of life and only one gave the results for this outcomeOutcomes are measures of health (for example quality of life, pain, blood sugar levels) that can be used to assess the effectiveness and safety of a treatment or other intervention (for example a drug, surgery, or exercise). In research, the outcomes considered most important are ‘primary outcomes’ and those considered less important are ‘secondary outcomes’., finding no benefit of EPO. No firm conclusions can be drawn
• None of the studies evaluated bleeding or anti-clotting effects, which have previously been associated with EPO and which is listed as a known cause of increased bleeding for people taking the medicine warfarin 
• None of the studies reported costs
• All but one studyAn investigation of a healthcare problem. There are different types of studies used to answer research questions, for example randomised controlled trials or observational studies. took place in developed countries so results may not be generalizable elsewhere

Lead researcher Joel Bamford said

Given the strength of the evidence in our review, we think further studies on the use of these complementary therapies to treat eczema would be hard to justify.

On the evidence of this review, EPO and BO represent a waste of money for eczema sufferers looking for relief from their symptoms. What’s more, previous research has shown that for anyone taking warfarin there’s an increased riskA way of expressing the chance of an event taking place, expressed as the number of events divided by the total number of observations or people. It can be stated as ‘the chance of falling were one in four’ (1/4 = 25%). This measure is good no matter the incidence of events i.e. common or infrequent. of bleeding when taking EPO. Both EPO and BO are commercially advertised on the internet as treatments for eczema – surely it’s time that changed?

Link:

Bamford JTM, Ray S, Musekiwa A, van Gool C, Humphreys R, Ernst E. Oral evening primrose oil and borage oil for eczema. Cochrane Database of Systematic ReviewsIn systematic reviews we search for and summarize studies that answer a specific research question (e.g. is paracetamol effective and safe for treating back pain?). The studies are identified, assessed, and summarized by using a systematic and predefined approach. They inform recommendations for healthcare and research. 2013, Issue 4. Art. No.: CD004416. DOI: 10.1002/14651858.CD004416.pub2.

Cochrane summary http://summaries.cochrane.org/CD004416/oral-evening-primrose-oil-and-borage-oil-for-eczema

Evening primrose oil and borage oil do not help eczema symptoms, finds Cochrane review BMJ 2013;346:f2712

Williams HC. Evening primrose oil for atopic dermatitis. Time to say goodnight. BMJ. 2003 December 13; 327(7428): 1358–1359. doi:  10.1136/bmj.327.7428.1358