Eczema is one of the most prevalent skin conditions, which can be either endogenous (due to internal causes) or exogenous (due to external causes). Atopic dermatitis is a type of endogenous eczema in which an extreme dermal reaction occurs in the epidermis; the epidermis, in a cascade of events, becomes swollen and disintegrates, the skin becomes red and exudative and itchy. To treat such patients, usually corticosteroids, moisturizers and emollients are used. Evening Primrose Oil is extracted from the seeds of the plant evening primrose (Oenothera biennis). The flowers of this plant usually open at dusk and give off a pleasant scent. Evening Primrose Oil attracts attention ad a source for gamma-linolenic acid (GLA). The compounds present in evening primrose oil, especially γ-linolenic acid, are converted in the body by delta-6-desaturase first to Dihomo-γ-linolenic acid (DGLA) and then to Prostaglandin E1. This prostaglandin has anti-inflammatory and cell membrane stabilization properties. Evening primrose oil is anti-inflammatory, ant-allergic, corrector of essential fatty acid omega-6 deficiency and reducer of blood pressure.
In an open clinical trial, 20 patients with dry skin and atopic disposition (not true atopic dermatitis) applied EPO cream (12.5%) for 3 weeks to the lower part of their right leg. The other leg was regarded as control. In the treated leg, considerable increase in amount of sebum was observed (p<0.01), without any change in the amount of moisture loss through epithelium. In the control leg, moisture loss through the epithelium was significant (p<0.05). Also, increase in smoothness of skin was observed in the treated leg.
In a non-controlled trial, infants with atopic dermatitis were treated with GLA (3 g/day) for 28 days. Gradual improvement in erythema, excortication and lichenification was observed. Significant difference was observed with regard to itching (p<0.01) and antihistamine use (p<0.01). Also, considerable increase was observed in percentage of circulating CD8 cells. In 2 examinations, GLA decreased the need for topical steroids (about 70%) and other medications like oral steroids, antihistamines and antibiotics. Two independent studies with different methods showed that EPO can considerably decrease skin roughness as well.
A placebo-controlled, double-blind trial in children with atopic dermatitis demonstrated considerable improvement in the general intensity of dermatitis in children treated with GLA, regardless of occurrence of allergy mediated by IgE. Treatment with GLA increased the amount of omega-6 fatty acid in RBC membrane, especially in those treated with higher doses.
In a review of clinical trials conducted for treatment of atopic eczema with EPO in 1992, it was demonstrated that parallel placebo-controlled trials have shown considerable improvement caused by EPO. In comparison to the control group, patients treated with EPO manifested less inflammation, dryness, scaling and general severity.(1)