Vitamin D in atopic dermatitis, chronic urticaria and allergic contact dermatitis

Crisaborole combined with vitamin D demonstrates superior therapeutic efficacy over either monotherapy in mice with allergic contact dermatitis

This study evaluated the therapeutic efficacy and underlying mechanisms of crisaborole combined with vitamin D in the treatment of allergic contact dermatitis. While crisaborole, a phosphodiesterase 4 inhibitor, and vitamin D analogs are commonly used in the treatment of atopic dermatitis, their combined therapeutic potential in allergic contact dermatitis (ACD) remains unexplored. Given their anti-inflammatory properties, we hypothesized that the combination of crisaborole and vitamin D could offer superior efficacy in mitigating the symptoms and underlying mechanisms of allergic contact dermatitis. In vitro, HaCaT cells stimulated with tumor necrosis factor-α and interferon-γ were treated with a combination of crisaborole and vitamin D, followed by cytokine expression analysis. In vivo, male C57BL/6 mice were divided into five groups and treated accordingly: blank control, dinitrochlorobenzene-induced model, crisaborole alone, vitamin D alone, and a combination of crisaborole and vitamin D. On day 14, dorsal skin and ear thickness were measured, followed by comprehensive pathological evaluations. In vivo and in vitro experiments showed that the expression levels of inflammatory factors were significantly lower in the DNCB + VD + Cri group than in the DNCB group. Histological analyses revealed that, compared with the DNCB group, the combined treatment group significantly reduced epidermal hyperkeratosis, improved epidermal transdermal water loss, decreased dermatitis scores, and diminished mast cell infiltration. Moreover, it lowered the expression levels of IL-6, IL-4, TNF-α, iNOS, IL-17, CC chemokine ligand 2 (CCL2), and CC chemokine receptor 2 (CCR2). CCL2 recognizes CCR2 and stimulates inflammatory cells, enhancing the inflammatory response. Increased CCL2 expression correlates with heightened inflammation and dendritic cell infiltration in ACD, while downregulation of CCL2 attenuates inflammation. Thus, the combined use of crisaborole and vitamin D demonstrates superior therapeutic efficacy over monotherapy in a mouse model of ACD. The combination of vitamin D and crisaborole significantly reduces inflammation and epidermal hyperkeratosis in a mouse model of allergic contact dermatitis, demonstrating superior therapeutic efficacy compared to either treatment alone. This suggests that the combined therapy could be a promising approach for the prevention and treatment of allergic contact dermatitis.

Practical Approach to Hypersensitivity to Nonsteroidal Anti-Inflammatory Drugs (NSAIDs) in Children

BACKGROUND

We aimed to assess the real-life prevalence, patient profile, and clinical presentation of drug hypersensitivity to NSAIDs in children after an incidence of an adverse event during treatment, verified by a drug challenge test.

METHODS

We included 56 children, aged 4-18 years, referred to our allergy clinic due to the incidence of adverse reaction during treatment. Skin prick tests and a drug provocation test were performed in all patients. Diagnostics for persistent urticaria were performed.

RESULTS

In 56 patients suspected of drug allergy, we proved NSAID hypersensitivity in 17 patients (30.1%). In 84.9% (n = 47) of patients, the clinical manifestations of hypersensitivity revealed angioedema and urticaria. The most common culprit drug among NSAIDs in children was ibuprofen. Thirty-one (55.4%) reactions were immediate, and 25 (44.6%) were delayed or late. Previous history of allergy was a risk factor for NSAID hypersensitivity (p = 0.001). Vitamin D deficiency in the blood serum was a risk factor for NASID hypersensitivity (OR = 5.76 (95% Cl: 1.42-23.41)).

CONCLUSIONS

Hypersensitivity to NSAIDs is a difficult diagnostic problem in pediatric allergy. The most common manifestation of hypersensitivity to ibuprofen in children is acute urticaria and angioedema. Two important problems in the differential diagnosis are cofactors such as vitamin D levels and viral infections, which require further research.

Modulation of allergic contact dermatitis via gut microbiota modified by diet, vitamins, probiotics, prebiotics, and antibiotics

Allergic contact dermatitis is one of the most common recorded occupational diseases. There are many different substances that the skin comes into contact with on a daily basis and that can cause ACD, e.g., preservatives, surfactants, and antimicrobial agents. The development of a mouse model of ACD has provided insight into the immune mechanisms involved. Drugs used in the treatment of skin diseases have many side effects. Therefore, alternative methods of suppressing the immune response to reduce the symptoms of skin diseases are being sought. In recent years, high hopes have been placed on dietary modulation and supplementation to affect the intestinal microbial composition and promote anti-inflammatory responses. In addition, other studies have shown the crucial role of intestinal microbiota in many immune-mediated diseases. Recognition and characterization of pro- and anti-inflammatory nutrients and supplements may be crucial to support the treatment of diseases such as atopic dermatitis, acne vulgaris, psoriasis, and allergic contact dermatitis.

Mast Cells and Vitamin D Status: A Clinical and Biological Link in the Onset of Allergy and Bone Diseases

The immune system is made up by an extremely composite group of cells, whose regulated and harmonious activity is fundamental to maintain health. The mast cells are an essential effector of inflammatory response which is characterized by a massive release of mediators accumulated in cytoplasmic secretory granules. However, beyond the effects on immune response, mast cells can modify bone metabolism and are capable of intervening in the genesis of pathologies such as osteoporosis and osteopenia. Vitamin D is recognized to induce changes in bone metabolism, but it is also able to influence immune response, suppressing mast cell activation and IgE synthesis from B cells and increasing the number of dendritic cells and IL-10-generating regulatory T cells. Vitamin D deficit has been reported to worsen sensitization and allergic manifestations in several different experimental models. However, in clinical situations, contradictory findings have been described concerning the correlation between allergy and vitamin D deficit. The aim of this review was to analyze the close relationships between mast cells and vitamin D, which contribute, through the activation of different molecular or cellular activation pathways, to the determination of bone pathologies and the onset of allergic diseases.

Vitamin D supplementation in patients with atopic dermatitis, chronic urticaria and contact irritant and allergic dermatitis - possible improvement without risk

Abstract.

Systemic and local cytokine profile and risk factors for persistent allergic airway inflammation in patients sensitised to house dust mite allergens

Objective

To evaluate cytokine profile, vitamin D status, symptom score and quality of life in patients with persistent allergic airway diseases sensitised to house dust mites (HDM) in comparison with healthy individuals.

Material and methods

Patients sensitized to HDM with persistent AR and having symptoms for at least 2 years with or without AA were involved into the study. Measurements of vitamin D level in serum and IL-10, IL-13, IL-17, IL-22, IL-33 and IFN-gamma in serum and nasal lavage were performed by ELISA.

Results

Eighty-one subjects were involved into the study. Serum IL-10 concentration was higher in patients with AR than in patients with AR and AA (6.71 ± 1.73 vs. 1.98 ± 0.24, p < 0.05). IFN-gamma level in nasal lavage was higher in patients with AR and AA than in patients with AR (p < 0.01) and healthy individuals (p < 0.05) (7.50 ± 0.37 vs. 6.80 ± 0.99 vs. 6.50 ± 0.22). Serum IL-22 negatively correlated with IL-22 in nasal lavage, whereas serum IFN-gamma positively correlated with IFN-gamma in nasal lavage. Positive correlation between serum IL-17 and total IgE and negative correlation between IL-17 in nasal lavage and eosinophils in nasal smear were found in patients with AR and AA. Serum IFN-gamma decreased the risk of AR for healthy individuals. Serum IL-10 and vitamin D decreased risk for development of AA for patients with AR. IL-22 in serum and IL-10 and IL-33 in nasal lavage increased this risk.

Conclusion

Novel cytokines such as IL-22, IL-17 and IL-33 and vitamin D may be involved in pathogenesis of persistent airway inflammation in patients sensitized to HDM.

The Role of Bradykinin Receptors in the Etiopathogenesis of Chronic Spontaneous Urticaria

Background and Objectives: Chronic spontaneous urticaria (CSU) is a distressing skin condition, which manifests as red, swollen, itchy, and sometimes painful hives or wheals appearing on skin. Recently, CSU has been associated with bradykinin release, which was previously discovered to be the main trigger of hereditary angioedema attacks. To study the role of bradykinin receptors 1 (BR1) and 2 (BR2) in the etiopathogenesis of CSU. Materials and Methods: A total of 60 individuals, 30 patients with CSU and 30 healthy subjects, were recruited to the study. CSU was diagnosed in accordance with the standardized protocol of dermatological assessment of skin symptoms. The level of bradykinin receptors was determined in populations of CD3⁺, CD4⁺, and CD8⁺ lymphocytes as well as in CD14⁺⁺CD16⁻, CD14⁺⁺CD16⁺ and CD14⁺CD16⁺ monocytes. In addition, urticaria activity score summed over 7 days (UAS-7) was assessed and correlated with BR1 and BR2 expression. Results: A statistically significant higher concentration of BR1 expression in lymphocytes was found in patients with CSU, compared to the control group (p < 0.001). Moreover, a statistically significant positive correlation was observed between UAS-7 and BR1/BR2 expression in CD14⁺⁺CD16⁻ cells (p = 0.03, R = 0.4). Conclusions: Bradykinin receptors are elevated in selected populations of lymphocytes in symptomatic CSU patients compared to healthy controls, indicating their role in the etiopathogenesis of the disease.

Vitamin D receptor gene polymorphisms in atopy

Background

The occurrence of allergic conditions, for example allergic asthma, rhinitis, and atopic dermatitis, is rising worldwide. These allergic conditions are associated with poor life quality. Vitamin D is proposed to be linked with increased risk and severe forms of allergic diseases.

Aims

This review article aimed to evaluate the vitamin D level role and polymorphisms of vitamin D receptor gene (VDR) in atopy.

Methods & Materials

We analyzed publications that were focusing on levels of vitamin D and/or polymorphism analysis of vitamin D receptor gene in allergic asthma, rhinitis, and atopic dermatitis patients.

Results

We noticed that levels of vitamin D are extensively studied in atopy by many research groups, however, polymorphisms of vitamin D receptor gene and their link with levels of vitamin D lack comprehensive data. There is evidence that vitamin D may be associated with anti‐inflammatory effects in allergic diseases. Some of VDR polymorphisms also may play a role in pathogenesis of these diseases. However, the data from different studies are controversial.

Discussion

The results of different studies are usually inconsistent, most probably due to populational bias or differences in methodology. Even though, more evidence shows a positive impact of vitamin D on the risk and outcomes of allergic diseases, especially atopic dermatitis, and asthma.

Conclusions

There is controversial data about the level of vitamin D and its role in atopy; however, more evidence shows a positive impact on the risk and outcomes of allergic diseases.

Significant association between Taq1 gene polymorphism in vitamin D receptor and chronic spontaneous urticaria in the Northeast of Iran

OBJECTIVE

Chronic spontaneous urticaria (CSU) is defined as urticaria with an unknown etiology which persists for more than 6 weeks. CSU is an uncomfortable cutaneous condition that occurs due to an immune-mediated inflammatory reaction. Many studies have demonstrated that vitamin D deficiency and single-nucleotide polymorphisms in the vitamin D receptor (VDR) impact the immune response. In the current study, the frequency of the Taq1 polymorphism in the VDR gene were compared between patients with CSU and individuals without CSU.

METHODS

In a case-control study, a group of CSU patients (n = 100) was compared with a group of healthy age- and gender-matched individuals as a control group (n =100) who visited our center between 2015 and 2017. After DNA extraction from EDTA-containing blood, polymerase chain reaction (PCR-RFLP) was used to determine the presence of the Taq1 polymorphism. Serum vitamin D levels were measured using ELISA method (Abcam, Cambridge, USA).

RESULTS

Genotyping for Taq1 polymorphism showed that TT, Tt and tt genes frequency in the CSU group were 36%, 54%, and 10% respectively. The TT, Tt and tt genotypes had a distribution of 50%, 47% and 3% respectively in the control group. The mean serum vitamin D level in the CSU group was 19.88 ± 8.14 ng/ml, which was not significantly correlated with the Taq1 polymorphism (P = 0.841). There was a significant relationship between Taq1 gene polymorphism (tt genotype) and CSU (P = 0.038). Tt genotype increased the risk of CSU (odds ratio = 1.596), and inheritance of tt genotype increased the risk even further (odds ratio = 4.630).

CONCLUSION

The frequency of Taq1 genotype polymorphism in the VDR gene was significantly higher in patients with CSU compared to the control group. The tt genotype polymorphism may be a risk factor for CSU.

Vitamin D3-Induced Promotor Dissociation of PU.1 and YY1 Results in FcεRI Reduction on Dendritic Cells in Atopic Dermatitis

Atopic dermatitis (AD) is a severe inflammatory skin disease. Langerhans cells and inflammatory dendritic epidermal cells (IDEC) are located in the epidermis of AD patients and contribute to the inflammatory processes. Both express robustly the high-affinity receptor for IgE, FcεRI, and thereby sense allergens. A beneficial role of vitamin D₃ in AD is discussed to be important especially in patients with allergic sensitization. We hypothesized that vitamin D₃ impacts FcεRI expression and addressed this in human ex vivo skin, in vitro Langerhans cells, and IDEC models generated from primary human precursor cells. We show in this article that biologically active vitamin D₃ [1,25(OH)₂-D₃] significantly downregulated FcεRI at the protein and mRNA levels of the receptor's α-chain, analyzed by flow cytometry and quantitative RT-PCR. We also describe the expression of a functional vitamin D receptor in IDEC. 1,25(OH)₂-D₃-mediated FcεRI reduction was direct and resulted in impaired activation of IDEC upon FcεRI engagement as monitored by CD83 expression. FcεRI regulation by 1,25(OH)₂-D₃ was independent of maturation and expression levels of microRNA-155 and PU.1 (as upstream regulatory axis of FcεRI) and transcription factors Elf-1 and YY1. However, 1,25(OH)₂-D₃ induced dissociation of PU.1 and YY1 from the FCER1A promotor, evaluated by chromatin immunoprecipitation. We show that vitamin D₃ directly reduces FcεRI expression on dendritic cells by inhibiting transcription factor binding to its promotor and subsequently impairs IgE-mediated signaling. Thus, vitamin D₃ as an individualized therapeutic supplement for those AD patients with allergic sensitization interferes with IgE-mediated inflammatory processes in AD patients.

Participation of the coagulation system and fibrinolysis as well as selected biomarkers in pathogenesis of chronic urticaria with various activity degree

Introduction

Chronic urticaria is a complex disease process in which chronic spontaneous urticaria (CSU) and chronic inducible urticaria are distinguished. Its etiopathogenesis still remains unknown. Some recent studies indicated a significant participation of vitamin D in the etiopathogenesis of urticaria. In 40–50% of patients with CSU on the basis of the positive result of the autologous serum skin test (ASST), autoimmunological background of the disease is diagnosed. Moreover, numerous test results confirm involvement of the coagulation system/fibrinolysis and non-infectious inflammatory factors in the pathophysiology of CSU.

Aim

To determine whether some factors may play a role in pathogenesis and contribute to the severity of chronic spontaneous urticaria.

Material and methods

One hundred and forty-two patients with diagnosed CSU were enrolled in the study. The activity of urticaria was assessed using the UAS-7 (Urticaria Activity Score). The study participants were divided into 4 groups depending on the UAS-7. ASST was performed and blood was collected to determine the biomarkers (CRP, vitamin D, D-dimers, fibrinogen, MPV, PLT).

Results

Statistical analysis was performed using Statistica 13. A statistically significant difference between groups with various activity of urticaria in D-dimer concentration average values (p < 0.05) was observed. Moreover, a statistically significant negative correlation between activity of urticaria and vitamin D concentration (p < 0.001) was noted.

Conclusions

Our results might support the possible involvement of both coagulation and fibrinolysis pathway and vitamin D in the urticaria pathomechanism. Further prospective studies in larger populations conducted at multiple centres are required to expand further our findings.

Association Between Vitamin D Receptor Gene Polymorphism rs2228570 and Allergic Rhinitis

Background

Vitamin D receptor (VDR) gene polymorphisms are involved in a variety of immune-related diseases, and VDR is associated with allergic rhinitis. The present study explored the associations between VDR gene polymorphisms and allergic rhinitis in the Chinese population.

Methods

The study population consisted of 400 patients with allergic rhinitis and 400 healthy controls. General characteristics were determined by interview. Blood DNA was extracted and genotyping was performed via matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The associations of each genetic variant with risk for AR were assessed by calculating the odds ratio (OR) with 95% confidence interval (95% CI).

Results

No significant differences were observed in general characteristics between cases and controls. The distributions of genotypes at the rs2228570 locus of the VDR gene conformed to Hardy–Weinberg equilibrium. There was a significant difference in the distribution of rs2228570 genotype (P<0.001) between cases and controls. Compared to GG and GA genotypes, the AA genotype increased the risk of AR (OR=3.27, 95% CI: 2.10–5.11, P=0.000; OR=2.58, 95% CI:1.63–4.08, P<0.001). Similar results were also observed in the dominant model (OR=1.64, 95% CI:1.24–2.17, P<0.001) and codominant model (OR=2.95, 95% CI:1.93–4.51, P<0.001). The A allele was still associated with elevated risk gene for AR after adjusting for potential confounding factors. Subgroup analyses indicated an interaction between alcohol and rs2228570 in the risk of allergic rhinitis. The A allele also increased the risk for AR in the population without asthma (OR=1.85, 95% CI:1.46–2.34, P<0.001).

Conclusion

VDR gene polymorphism is associated with AR, and the AA genotype of rs2228570 is associated with the increased risk of AR in the Chinese population.

Correlation between asthmatic infants with rickets and vitamin D, inflammatory factors and immunoglobulin E

Correlation between asthmatic infants with rickets and vitamin D, inflammatory factors and immunoglobulin was investigated. A total of 60 child patients with asthma who met the inclusion criteria and received treatment from January 2016 to October 2017 were collected. Among them, 17 asthmatic infants with rickets were set as observation group, while 43 child patients with simple asthma were regarded as the control group. Venous blood was drawn from the two groups of subjects after admission. The levels of interleukin-1 (IL-1), IL-6 and IL-17 in serum were determined by ELISA, vitamin D and immunoglobulin E levels in serum were detected using a fully-automatic biochemical analyzer, and wheezing duration during asthma attack was recorded. IL-1, IL-6, IL-17 and immunoglobulin E levels in serum of observation group were significantly higher than those of the control group (P<0.05). The vitamin D level in the observation group was remarkably lower than that in the control group (P<0.05). Wheezing duration in observation group was evidently longer than that in control group (P<0.05). Moreover, IL-1, IL-6, IL-17 and immunoglobulin E levels in serum were positively related to wheezing duration, but the vitamin D level was negatively associated with wheezing duration. Infantile asthma with rickets is closely correlated with vitamin D, inflammatory factors and immunoglobulin E, which are major risk factors in infantile asthma with rickets.

Dietary habits in Japanese patients with chronic spontaneous urticaria

BACKGROUND

Chronic spontaneous urticaria (CSU) is defined as the spontaneously appearing weals and/or angioedema for more than 6 weeks. Dietary habits can modulate the pathogenesis of CSU. However, dietary intakes of nutrients or food in CSU patients, compared with healthy controls, have not been examined in quality and quantity.

METHODS

We evaluated dietary habits in adult Japanese patients with chronic spontaneous urticaria using a validated, brief-type self-administered diet history questionnaire and compared the results to those of age- and sex-matched healthy controls. The severity of CSU was evaluated using the Urticaria Control Test.

RESULTS

Japanese CSU patients showed higher body mass indices, higher intakes of eggs, vegetables other than green/yellow vegetables/mushrooms/algae, cholesterol, folic acid, dietary fibres, vitamin D, vitamin K, Cu, Fe, Pi, Ca, Mg, Na and salt, and lower intake of alcohol, compared to controls. The logistic regression analysis showed that CSU was associated with high body mass index and high intake of eggs. The intake of beverages was higher in uncontrolled CSU patients (Urticaria Control Test ≦11 points) than in controlled patients. The logistic regression analysis showed that uncontrolled CSU was associated with high intake of beverages. The intake of coffee, caffeine-rich and non-alcohol beverage, in uncontrolled CSU patients was higher than that in controlled patients.

CONCLUSIONS

Chronic spontaneous urticaria was associated with high body mass index and high intake of eggs. Uncontrolled CSU was associated with high intake of beverages. Further studies should elucidate the relationships of these results with the development or exacerbation of CSU.

Effect of Cholecalciferol Supplementation on Treatment Response and IL-10 Level in Vitamin D Deficient Parthenium Dermatitis Patients: A Randomized Double-Blind Placebo-Controlled Trial

Allergic contact dermatitis following exposure to Parthenium is a chronic disease associated with frequent relapses and significant disturbance in the quality of life. The affected patients have lower circulating levels and decreased expression of IL-10. Hence, measures to increase its level may enhance the therapeutic outcome. The clinical trial was undertaken to evaluate the effect of cholecalciferol supplementation on treatment response and IL-10 level in Parthenium dermatitis patients with vitamin D deficiency. A total of 72 patients were recruited and randomized to receive either cholecalciferol tablet 60,000 IU per week or matching placebo for 8 weeks with standard background treatment. Eczema Area Severity Index (EASI) and Dermatology Life Quality Index (DLQI) were assessed at baseline, 4 weeks, and 8 weeks while IL-10 and serum 25-hydroxyvitamin D levels were measured at baseline and 8 weeks. Levels of 25-hydroxyvitamin D and IL-10 showed a significant rise in both placebo and vitamin D groups following the intervention. The relatively higher increase in IL-10 level observed in the vitamin D group was statistically insignificant compared to placebo group. Significant reduction in EASI, as well as DLQI scores, was noted after 1 and 2 months, but the reduction in these scales was not significantly different between the groups. Cholecalciferol supplementation for 2 months did not reduce the disease severity in clinically diagnosed Parthenium dermatitis patients. However, treatment initiation significantly improved plasma IL-10 levels after 2 months in both placebo and cholecalciferol groups.

Evaluation of 1,25-dihydroxyvitamin D3 pathway in patients with chronic urticaria

BACKGROUND

Previous studies showed the role of vitamin D (Vit D) on the progression of chronic urticaria. To the best of our knowledge, there are no other results regarding the contribution of single nucleotide polymorphisms (SNPs) in the vitamin D receptor (VDR) and vitamin D binding protein (VDBP) genes in chronic urticaria (CU).

AIM

In the present study, we investigated the Vit pathway and the association between VDR and VDBP gene polymorphisms and CU risk in Iranian population.

METHODS

All participating individuals in the present study were evaluated for serum Vit D and VDBP concentration VDR rs1544410 and rs2228570 and VDBP rs7041using a polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis. The associations of studied analytes and three SNPs with clinical and laboratory outcomes were investigated in CU patients.

RESULTS

Patients with CU showed lower Vit D compared to controls (19.26 ± 1.26 vs. 31.72 ± 7.14 ng/ml, P-value = 0.006). There was a significant correlation between Vit D levels and urticaria activity score. Serum VDBP was significantly higher in CU patients than controls (1317.3 ± 183.71 vs. 395.77 ± 12.96 µg/ml, P-value <0.0001) and had a positive correlation to progression of CU. The A allele of this polymorphism might be a potential risk factor for progression of CU [odds ratio 4.3434, 95% confidence interval (1.7331-10.8852), Z-statistic = 3.133, P-value = 0.0017].

CONCLUSION

In summary, this study demonstrated that change in Vit D pathway in the level of gene or protein may be a risk factor for progression of CU.

Serum 25-hydroxyvitamin D levels in patients with skin diseases including psoriasis, infections, and atopic dermatitis

The pathogenetic role of vitamin D as well as its clinical correlation in inflammatory skin diseases is still uncertain. This study aimed to compare serum levels of 25(OH) vitamin D (calcidiol) in outpatients suffering from different skin diseases using the same laboratory method in one study. In routine serum samples of 1,532 patients from the previous 12 months we identified retrospectively 180 (mean age 49.4 years, 80 female, 100 male) and 205 (mean age 36.3 years, 116 female, 89 male) patients with psoriasis (PSO) and atopic dermatitis (AD), respectively. Clinical disease activity and quality of life was evaluated using Physicians Global Assessment Scores (PGA), Dermatology Life Quality Index (DLQI), and a Visual Analog Scale for pruritus in AD, respectively. The median 25(OH)D serum level of all patients (22.97 ng/mL, range 2.61–96.0, n = 1,461) was significantly lower in comparison to healthy controls (41.6 ng/mL, range 16.9–77.57, p < 0.0001, n = 71). In PSO and AD we measured 21.05 ng/mL (44% < 20 ng/mL) and 22.7 ng/mL (39% < 20 ng/mL), respectively (p = 0.152). Among all subgroups, patients with severe acute or chronic infectious skin diseases had the lowest median 25(OH)D serum levels (17.11 ng/mL, n = 94, 66% <20 ng/mL, p < 0,001 vs. AD, p = 0,007 vs. PSO). For PSO and AD there was no significant correlation between 25(OH)D levels and PGA scores and DLQI values, respectively, or the extent of pruritus in AD. 25(OH)D serum levels in inflammatory skin diseases might correlate more with the type of disease and the degree of inflammation than with clinical activity itself.

Extraskeletal actions of vitamin D

The vitamin D receptor (VDR) is found in nearly all, if not all, cells in the body. The enzyme that produces the active metabolite of vitamin D and ligand for VDR, namely CYP27B1, likewise is widely expressed in many cells of the body. These observations indicate that the role of vitamin D is not limited to regulation of bone and mineral homeostasis, as important as that is. Rather, the study of its extraskeletal actions has become the major driving force behind the significant increase in research articles on vitamin D published over the past several decades. A great deal of information has accumulated from cell culture studies, in vivo animal studies, and clinical association studies that confirms that extraskeletal effects of vitamin D are truly widespread and substantial. However, randomized, placebo-controlled clinical trials, when done, have by and large not produced the benefits anticipated by the in vitro cell culture and in vivo animal studies. In this review, I will examine the role of vitamin D signaling in a number of extraskeletal tissues and assess the success of translating these findings into treatments of human diseases affecting those extracellular tissues.