Eczema and related skin diseases can be irritating at best, debilitating and very difficult to live with at worst. The data on hemp oil for eczema seem pretty conclusive—more research is needed, but dietary hemp oil has a role to play and could be a possible treatment. In contrast, research regarding CBD oil for eczema specifically is sparse. The result is that we can only speculate as to why it seems to work—because based on anecdotal evidence, it does. But more about that later.
First, let's look at what research says about hemp oil for eczema.
In a controlled, randomized, single-blind, crossover study conducted in Finland in 2005, the researchers concluded that ingested dietary hemp seed oil caused significant changes in plasma (blood) fatty acid profiles and improved clinical symptoms of atopic dermatitis.
"These preliminary results confirm anecdotal observations of improved skin quality after ingesting modest amounts of hemp seed oil on a daily basis, over a relatively short period of time. From these observations, further study is warranted to determine the value of the regular use of dietary hemp seed in the treatment of atopic dermatitis."
Technically, there is a slight difference between atopic dermatitis and eczema, but the terms are commonly used to refer to the same symptoms:
The said study's findings also suggest that dietary hemp oil's healing benefits may be attributed to the PUFAs, or polyunsaturated fatty acids in the oil.
These PUFAs include EFAs, or essential fatty acids, such as omega-3 and omega-6—long known for their importance in general and skin health. They are also known to play an important role in the immune response, which could further explain their effect on eczema.
Hemp seed oil can contain up to 80% of PUFAs and is a rich source of EFAs.
"...individuals who have used hemp seed oil for longer periods of time report increased strength in fingernails (months) and thicker hair (years), in addition to the improvements in skin conditions within weeks." 
So, over and above the symptom-ameliorating effect of taking hemp oil for eczema, this particular study reported other benefits, too.
Hemp oil is also rich in cannabidiol, or CBD, a compound found in hemp varieties of theCannabis sativa Lplant. CBD is also known for many healthful properties.
This study has not focused on CBD per se, but could this cannabinoid also play a role in these findings regarding eczema?
Research suggests it might.
First of all, the endocannabinoid system, where CBD action takes place, is known to play a part in the production of various hormones and proteins, including cytokines. Cytokines, in turn, are also involved in the body's immune response. Inflammation is a known symptom of a stressed or burdened immune system.
The endocannabinoid system comprises various receptors, their fatty or oily ligands, and regulatory enzymes. Receptors CB1 and CB2 are the most well-researched.
CB1 receptors are found mostly in the brain and central nervous system. An abundance of CB2 receptors is found in immune cells of peripheral organs, such as the skin, where they modulate the release of cytokines.
CBD shows most of its activity in these CB2 receptors and is associated with anti-inflammatory, antipruritic, and analgesic effects in the body. Therefore, it makes sense to assume that CBD oil could very well be a therapeutic option for eczema.
Despite the paucity of research, people who ingest CBD oil testify that it is indeed a therapy against this skin disorder.
Until recently, Cheryl Halliburton, 27, from the UK, suffered such bad eczema flare-ups that she couldn't leave the house at times. These regularly left her with cracked, open skin that developed into weeping wounds.
She says in an interview withMetroUK, "It really began when I fell pregnant with Alexis when I was around 23 years old. It started on my back and cleared up after a course of steroids but straight away it flared up on my face and neck and has been constant ever since."
She would develop these symptoms every few days after eating certain foods. Then, the itching would be unbearable.
"No cream I put on it would soothe it, in fact, it would often make it worse. I would feel like I wanted to rip my skin off."
Cheryl's eczema furthermore had no traceable cause, despite numerous tests. She was unable to wear makeup, and because of the discomfort and embarrassment caused by the flare-ups, she ended up isolating herself.
A turning point came after her husband, Craig, had to rush her to the hospital during a particularly bad episode.
"I couldn’t move my face and neck and there were open wounds on my chest that were weeping,” she says. "I was was cold and shaky and felt like I wanted to be sick, and was placed on a drip overnight to treat the infection that had gotten into my skin."
After this, out of desperation, Cheryl started taking CBD, first as an oil and then vaping it, and she experienced remarkable effects after only two weeks.
After years of suffering, all her eczema symptoms disappeared; Cheryl's skin was clear and it stayed clear even when she ate triggering foods, such as wine and bread.
Cheryl is deeply grateful for the effect of CBD oil on her condition. It now allows her to have a normal life, doing normal things. "I’ve been able to go shopping with my little girl, even go back to work. Alexis has noticed the difference as she always had to stay in the house with me." 
Both hemp oil and CBD oil for eczema should be researched in a more robust, clinical study before definitive conclusions can be drawn.