Hair pigmentation is regulated by follicular melanogenesis, in which the process consists of melanin formation and transfer to keratinocytes in the hair shaft. Human hair follicles contain two types of melanin: the brown‐black eumelanin and yellow‐red pheomelanin. Eumelanin is commonly present in black and brown hair while pheomelanin is found in auburn and blonde hair. Hair follicle melanogenesis is under cyclical control and is concurrently coupled to hair growth. Many factors including intrinsic and extrinsic factors affect the follicular melanogenesis. Though many studies have been conducted to identify the pathogenesis and regulation of hair pigmentation, the etiology of canities and hair pigmentation is still unclear. The pathogenesis of canities or gray hair is believed to occur either from insufficient melanin formation due to melanocyte degeneration or a defect in melanosomal transfer. Canities is an aging sign which often interferes with one's socio‐cultural adjustment. On the other hand, premature canities correlate with diseases such as osteopenia and cardiovascular disease. Risk factors associated with canities are not only genetic but also external causes. For example, smoking, alcohol consumption, and stress are among the most common factors. Camouflage techniques are still used as the primary treatment of canities. Further treatments for canities are being developed to achieve the true reversal of hair pigmentation.
BackgroundVitamin D has been reported to be associated with many allergic diseases. There are a limited number of the studies of vitamin D supplementation in patients with chronic spontaneous urticaria (CSU). This study aims to study the relationship between vitamin D and CSU in terms of serum vitamin D levels, and the outcomes of vitamin D supplementation.MethodsA literature search of electronic databases for all relevant articles published between 1966 and 2018 was performed. The systematic literature review was done following Preferred Reporting Items for Systematic Reviews and Meta-analysis recommendations.ResultsSeventeen eligible studies were included. Fourteen (1321 CSU cases and 6100 controls) were concerned with serum vitamin D levels in CSU patients. Twelve studies showed statistically significant lower serum vitamin D levels in CSU patients than the controls. Vitamin D deficiency was reported more commonly for CSU patients (34.3–89.7%) than controls (0.0–68.9%) in 6 studies. Seven studies concerned with vitamin D supplementation in CSU patients showed disease improvement after high-dosages of vitamin D supplementation.ConclusionCSU patients had significantly lower serum vitamin D levels than the controls in most studies. However, the results did not prove causation, and the mechanisms were not clearly explained. Despite the scarcity of available studies, this systematic review showed that a high dosage of vitamin D supplementation for 4–12 weeks might help to decrease the disease activity in some CSU patients. Well-designed randomized placebo-controlled studies are needed to determine the cut-off levels of vitamin D for supplementation and treatment outcomes.
Background. Antinuclear antibody (ANA) is often used as a screening test for autoimmune comorbidities in patients with chronic spontaneous urticaria (CSU). However, the relationship of ANA status and the clinical course of the disease have not been fully described. Objectives. To compare clinical features of CSU patients who are positive and negative for ANA. Methods. This was a retrospective cohort study that enrolled CSU patients attending the Urticaria Clinic at Siriraj Hospital from 2013 to 2019. Demographics, clinical characteristics, laboratory investigations, and treatments were collected until July 2021. All patients were investigated for ANA. Clinical feature data was compared between CSU patients with positive ANA and negative ANA groups using the 2-sample t -test and the Mann–Whitney U test for quantitative variables. The chi-squared test or Fisher’s exact test was conducted to explore the association of qualitative variables. Disease relapse and remission were analysed via Kaplan-Meier survival analysis. Results. Of 323 CSU patients, 31% had positive ANA. There were no significant differences in disease severity or impairment in quality of life. Patients with a positive ANA test had significantly lower prevalence of allergic rhinitis ( p = .048 ) and significantly higher level of erythrocyte sedimentation rate ( p = 0.007 ). Kaplan-Meier survival analysis showed that 2% of ANA positive CSU patients achieved remission status after one year and 28% did so after five years. There was no statistically significant difference in time to remission and time to relapse between ANA-positive and negative groups. Conclusion. Positive ANA in CSU patients could not indicate the differences in main disease characteristics from the ANA-negative CSU patients. Investigation for ANA may be useful in CSU patients who are suspected of having autoimmune diseases.
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