Psoriasis and atopic eczema: Vitamin D may improve symptoms by attenuating lesions and reducing inflammation

Vitamin D may represent an effective treatment to improve the symptoms of psoriasis and atopic dermatitis, reducing skin lesions. 

Vitamin D regulates many physiological processes in the skin, such as cell proliferation, immune functions, and maintenance of the skin barrier. Supporting this link, some studies have shown that vitamin D deficiency is associated with a higher risk of developing eczema and psoriasis.

This is reported in a study published in the journal Skin Pharmacology and Physiology by researchers from the Department of Translational Medicine at Sidra Medicine Center, Qatar. 

Psoriasis and atopic dermatitis, two widespread inflammatory diseases 

Psoriasis and atopic dermatitis (or atopic eczema) are chronic inflammatory skin diseases that affect both adults and children. 

Psoriasis is characterized by increased skin proliferation, with red and scaly lesions appearing on the skin. These lesions can occur anywhere on the body, causing pain, itching, cracking, and bleeding. 

There are different types of psoriasis of varying severity, affecting almost 3% of the world’s population. The disease often appears between the ages of 15 and 35 but can also manifest in infants and the elderly. The causes of this disease are related to the immune system and have a genetic basis. In people affected by psoriasis, the immune system is incorrectly activated, causing too rapid growth of skin cells that accumulate in the upper layers of the skin, causing lesions on the surface. The disease course is not constant: it can worsen at times and in some cases disappear for a period (spontaneous remission). 

Psoriasis is a disorder that in most cases requires treatment throughout life. Numerous drugs are available that can be applied directly to the skin or taken orally, but it may take time to find the most suitable treatment or combination of treatments. 

Atopic dermatitis is a chronic skin disease triggered by interactions involving the environment, genetic and immunological factors, characterized by chronic inflammation and epithelial barrier breakdown. Symptoms often depend on age and are almost always associated with intense itching; eczema may also occur with asthma, allergic rhinitis, food allergies, urticaria, and hypersensitivity to various stimuli. 

The causes of atopic dermatitis are unknown, but there is certainly a genetic predisposition underlying this disease. Environmental factors and lifestyle play an important role as triggers. The course of atopic dermatitis is recurrent, with episodes of varying severity and duration. Spontaneous recoveries are possible, especially atopic dermatitis in children, which heals in 80% of cases within a few years. Treatments vary from the use of moisturizing creams to local corticosteroid preparations. 

The role of vitamin D in inflammatory skin diseases 

The causes of inflammatory skin diseases are varied and include genetic and environmental factors. Among these, diet is also considered important, especially regarding the role of fatty acids and vitamins. 

For a long time, vitamin D’s main function was considered to be maintaining normal bone architecture by regulating calcium and phosphorus metabolism, but in recent decades, various discoveries have highlighted other effects of the vitamin, including a role in regulating cell proliferation, cell differentiation, and immune system regulation. 

Regarding vitamin D’s action in the skin, it has been discovered that keratinocytes, the most abundant cell type in the epidermis, are the only cells able to synthesize vitamin D3 (cholecalciferol) from its precursor thanks to ultraviolet rays. Furthermore, keratinocytes can produce the active metabolite of vitamin D (calcitriol). Proper keratinocyte differentiation is important for epidermal barrier integrity and function. 

The review study links vitamin D with psoriasis and atopic dermatitis 

Based on previous research, the Qatar researchers conducted a review study on the role of vitamin D in skin physiology, focusing on its effects in certain inflammatory skin conditions. 

The study collected all scientific publications on the subject; in particular, a comprehensive literature search was conducted using the PubMed and Google Scholar databases and the keywords “vitamin D,” “skin,” “atopic dermatitis,” and “psoriasis.” Only articles published in English and related to the study topic were included. Results showed that vitamin D is fully connected to the skin through its synthesis, metabolism, and activity, and it can regulate numerous physiological skin processes such as cell proliferation, immune functions, barrier maintenance, and cell death. 

Many of the clinical studies reviewed suggested various positive effects of vitamin D in treating inflammatory skin diseases, especially psoriasis and atopic dermatitis. In particular, vitamin D supplementation can improve lesions caused by atopic dermatitis by restoring epidermal barrier defects and correcting immune response. Moreover, numerous clinical studies have shown that vitamin D is effective in treating psoriasis symptoms, especially when combined with corticosteroids, since the effects of both treatments are complementary. 

Vitamin D also appears to suppress inflammatory cytokines, substances present in very high amounts in psoriatic skin. Researchers reported that several population studies observed an increased likelihood of developing atopic dermatitis in individuals with low vitamin D levels and that serum concentrations were lower in children and adults with eczema compared to healthy controls. 

Study conclusions 

According to the researchers who conducted the study, vitamin D exerts a beneficial effect on the skin and could be an important therapeutic option for psoriasis and atopic dermatitis. 

Human skin acts as a site for vitamin D synthesis as well as a target organ for its biologically active form, which could represent a therapeutic option for many skin diseases. The authors themselves state that further studies are needed using more advanced technologies to better understand vitamin D’s actions and to assess the safety and efficacy of vitamin D-based treatment regimens in various inflammatory skin diseases. 

Source: Umar M. Sastry K. S. Al Ali F. Al-Khulaifi M. Wang E. Chouchane A. I. “Vitamin D and the Pathophysiology of Inflammatory Skin Diseases”. Skin Pharmacology and Physiology.