Eczema is a chronic skin inflammatory condition which causes extreme itchy skin rashes that results in severe discomfort to the affected individual. However, it is not a communicable or infectious skin disease.
The symptoms of eczema include unbearable itching, skin swelling, red rashes, blister formations and sometimes oozing occur through these blisters. Excessive itching diverts mental focus and causes sleep disturbance.  Eczema prevalence is quite high.
Almost 30 percent Americans suffer from eczema.  Although the children and adolescents are mostly affected, the condition is even found in adults.
Several medicines, including steroidal drugs, antihistamines are recommended to treat the condition, but the continuous application of these medications may provide some side effects.
Therefore, medicinal products of natural origin is always a blessing for Eczema patients as it reduces the severity without any adverse effects. The scientific evidence supports the therapeutic benefits of black seed oil also reveals its effectiveness against eczema. 
Why Is Black seed selected for treating Eczema?
The phytochemicals composition of black seed is primarily responsible for its efficiency to combat eczema and provide a choice of side effect free therapeutic option with improving skin condition. Thymoquinone, dithymoquinone, thymol, thymohydroquinone, alphahederin, carvacrol, nigellicine, nigellimine, and nigellidine are some bioactive ingredients present in the black seed which provide multiple dermatological (skin related) therapeutic benefits, including eczema controlling effect. Usually, the oil extracted from black seed is the most convenient way to obtain these benefits. 
Mechanism of action of Black seed to combat Eczema
According to the clinical experts, the inflammatory response damages the corneal layer of the skin and hence the protective effect of the skin gets hampered. Therefore, the germs and allergens trigger the antibody production which causes the swelling of the skin. In addition, mutation of the gene due to oxidative stress causes a decreased rate of skin protein (filaggrin) synthesis, which imbalance fat content in the cutaneous layer and leads to a deficiency of skin moisture.  This dry scaly skin causes itching.  Following are some of the mechanism of action of black seed to combat eczema:
• Black seed possesses potential anti-oxidant property. The antioxidant property prevents abnormal genetic mutation by preventing DNA damage and thus maintain the protein synthesis and lipid content in the skin.
• The anti-inflammatory effect of black seed reduces white blood cells counts, bacterial growth and skin tissue destruction and benefits of this leads to prevent skin inflammatory condition and localized infections.
• Application of black seed accelerates wound healing process by uplifting fibroblast growth factor and transforming growth factor beta.
• The scope of skin infection development from eczema is minimized by black seed administration due to its wide range of antimicrobial effect, which prevents further infection.
• Black seed can control the hypersensitivity reaction by blocking the histamine release from the mast cell and further reduce the allergen-induced hyper-reactivity and control skin reactions including eczema related inflammation and itching.
• Black seed application improves epidermal-barrier functionality, which provides potential protection from a germ or other foreign objects, which trigger an inflammatory response of the skin and prevents eczema.
• Black seed also improves the moisture content of the skin and controls itching by removing dryness.
• In addition, combination therapy of the black seed oil with other therapeutic agents can also improve the potentiality of the medication by improving permeability of the skin. 
Scientific evidence supports the Black seed oil efficacy against eczema
There are research evidence and clinical trial data that support the efficacy of black seed against eczema.
A double-blinded, randomized, controlled clinical trial was conducted to check the efficacy of black seed on 60 patients having hand eczema between 18-60 years of age. Eucerin and Betamethasone were the two comparator medicines selected against black seed in this trial. Eucerin is a popular dermatological brand for skin care and Betamethasone is a steroid medication for treating eczema with varied steroidal side effects.
The test result showed that black seed is more effective to treat eczema than Eucerin; whereas black seed and Betamethasone have similar efficacy to treat eczema. The author of this study concluded that black seed can able to treat severe eczema and improve the quality of life of the patients.