Psoriasis and atopic eczema: vitamin D may improve symptoms by alleviating lesions and reducing inflammation

Vitamin D could be an effective treatment in improving the symptoms of psoriasis and atopic dermatitis by reducing skin lesions. 

In fact, vitamin D regulates many physiological processes in the skin, such as cell proliferation, immune functions, and maintenance of the skin barrier. Confirming the link, studies have shown that a vitamin D deficiency is associated with an increased risk of the onset of eczema and psoriasis.

This is according to a study published in the journal Skin Pharmacology and Physiology by researchers from the Department of Translational Medicine at the Sidra Medicine center in Qatar. 

Psoriasis and atopic dermatitis, two widespread inflammatory diseases 

Psoriasis and atopic dermatitis (or atopic eczema) are inflammatory skin conditions with a chronic course, affecting both adults and children. 

Psoriasis is characterized by increased proliferation of the skin, on which red, scaly lesions appear; these lesions can occur anywhere on the body causing pain, itching, cracking, and bleeding. 

There are different types of psoriasis of varying severity, affecting nearly 3% of the world's population. The disease often occurs between 15 and 35 years of age, but can also appear in infants and the elderly. The causes of this disease are related to the immune system and have a genetic basis. In people with psoriasis, the immune system is activated incorrectly, causing skin cells to grow too fast and accumulate in the upper layers of the skin, causing lesions to form on the surface. The course of the disease is not constant: sometimes it may worsen and in some cases it may disappear for a period (spontaneous remission). 

Psoriasis is a disorder that in most cases requires lifelong treatment. Numerous medications are available, which can be directly applied to the skin or taken orally, but it can take time to identify 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, and is characterized by chronic inflammation and breakdown of the epithelial barrier. Symptoms of the disease often depend on age, and are almost always associated with intense itching; in addition, eczema may manifest with asthma, allergic rhinitis, food allergies, hives, and hypersensitivity to a wide variety of stimuli. 

The causes of atopic dermatitis are unknown, but underlying this disease is definitely a genetic predisposition. Environmental factors and lifestyle habits play important roles as triggers. The course of atopic dermatitis is recurrent, with episodes of varying severity and duration. Spontaneous recoveries are possible, however, especially atopic dermatitis in children heals in 80% of cases within a few years. Treatments for this condition are also diverse, ranging 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 different and include genetic and environmental factors. Among these among them, diet is also considered an important element, especially the role of fatty acids and vitamins. 

The main function of vitamin D has long been considered to be the maintenance of normal bone architecture, the calcium and phosphorus metabolism of which it regulates, but in recent decades, several discoveries have highlighted other effects of the vitamin, including a role in the regulation of cell proliferation, cell differentiation, and regulation of the immune system. 

Regarding the action of Vitamin D in the skin, it has been found that keratinocytes, the most abundant cell type in the epidermis, are the only cells that are able to synthesize Vitamin D3 (cholecalciferol) from its precursor due to ultraviolet light. Keratinocytes, in addition, can produce the active metabolite of Vitamin D (calcitriol). Proper differentiation of keratinocytes is important for epidermal barrier integrity and function. 

Review study links vitamin D with psoriasis and atopic dermatitis 

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

All scientific publications on the topic were collected in the study; in particular, a comprehensive literature search was conducted using PubMed and Google Scholar databases and the keywords "vitamin D," "skin," "atopic dermatitis," and "psoriasis." Only articles published in English and related to the topic of the study were included. The results showed that vitamin D is integrally linked to the skin for its synthesis, metabolism, and activity, and is able to regulate numerous skin physiological processes, such as cell proliferation, immune functions, barrier maintenance, and cell death. 

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

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

Conclusions of the study 

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

Human skin acts as a site of vitamin D synthesis and also as a target organ for its biologically active form, which could be a therapeutic option for many skin diseases. However, according to the authors' own statement, further studies using state-of-the-art technologies are needed to better understand the actions of vitamin D, and to evaluate the safety and efficacy of vitamin D 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.