Topical use of calcipotriol does not potentiate squaric acid dibutylester effectiveness in the treatment of alopecia areata

Alopecia areata: a review of disease pathogenesis

BACKGROUND

Alopecia areata is a disorder that results in nonscarring hair loss. The psychological impact can be significant, leading to feelings of depression and social isolation. Objectives In this article, we seek to review the pathophysiological mechanisms proposed in recent years in a narrative fashion.

METHODS

We searched MEDLINE and Scopus for articles related to alopecia areata, with a particular emphasis on its pathogenesis.

RESULTS

The main theory of alopecia areata pathogenesis is that it is an autoimmune phenomenon resulting from a disruption in hair follicle immune privilege. What causes this breakdown is an issue of debate. Some believe that a stressed hair follicle environment triggers antigen presentation, while others blame a dysregulation in the central immune system entangling the follicles. Evidence for the latter theory is provided by animal studies, as well investigations around the AIRE gene. Different immune-cell lines including plasmacytoid dendritic cells, natural killer cells and T cells, along with key molecules such as interferon-γ, interleukin-15, MICA and NKG2D, have been identified as contributing to the autoimmune process.

CONCLUSIONS

Alopecia areata remains incurable, although it has been studied for years. Available treatment options at best are beneficial for milder cases, and the rate of relapse is high. Understanding the exact mechanisms of hair loss in alopecia areata is therefore of utmost importance to help identify potential therapeutic targets.

The Role of Micronutrients in Alopecia Areata: A Review

Alopecia areata (AA) is a common, non-scarring form of hair loss caused by immune-mediated attack of the hair follicle. As with other immune-mediated diseases, a complex interplay between environment and genetics is thought to lead to the development of AA. Deficiency of micronutrients such as vitamins and minerals may represent a modifiable risk factor associated with development of AA. Given the role of these micronutrients in normal hair follicle development and in immune cell function, a growing number of investigations have sought to determine whether serum levels of these nutrients might differ in AA patients, and whether supplementation of these nutrients might represent a therapeutic option for AA. While current treatment often relies on invasive steroid injections or immunomodulating agents with potentially harmful side effects, therapy by micronutrient supplementation, whether as a primary modality or as adjunctive treatment, could offer a promising low-risk alternative. However, our review highlights a need for further research in this area, given that the current body of literature largely consists of small case-control studies and case reports, which preclude any definite conclusions for a role of micronutrients in AA. In this comprehensive review of the current literature, we found that serum vitamin D, zinc, and folate levels tend to be lower in patients with AA as compared to controls. Evidence is conflicting or insufficient to suggest differences in levels of iron, vitamin B12, copper, magnesium, or selenium. A small number of studies suggest that vitamin A levels may modify the disease. Though understanding of the role for micronutrients in AA is growing, definitive clinical recommendations such as routine serum level testing or therapeutic supplementation call for additional studies in larger populations and with a prospective design.

Estimated serum vitamin D status, vitamin D intake, and risk of incident alopecia areata among US women

Studies have identified increased prevalence of vitamin D deficiency in patients with alopecia areata (AA), an autoimmune disease characterized by hair loss, but none have prospectively examined vitamin D status and incident AA. In 55,929 women in the Nurses' Health Study (NHS), we prospectively evaluated the association between estimated vitamin D status, derived from a prediction model incorporating lifestyle determinants of serum vitamin D, and self-reported incident AA. We evaluated dietary, supplemental, and total vitamin D intake as additional exposures. Using Cox proportional hazards models, we calculated age-adjusted and multivariate hazard ratios (HR) to evaluate risk of AA. We identified 133 cases of AA over a follow-up of 12 years. The age-adjusted HR between top vs. bottom quartiles for serum vitamin D score was 0.94 (95 % CI 0.60-1.48) and the corresponding multivariate HR was 1.08 (95 % CI 0.68-1.73). There was no significant association between dietary, supplemental, or total vitamin D intake and incident AA. This study does not support a preventive role for vitamin D in the risk of developing AA.

Off-label uses of topical vitamin D in dermatology: a systematic review

BACKGROUND

Topical vitamin D is approved by the US Food and Drug Administration for the treatment of psoriasis but is also used off-label in the treatment of a variety of cutaneous diseases despite a lack of evidence-based guidelines.

OBJECTIVE

The objective of this study was to provide evidence-based clinical guidelines for the off-label use of topical vitamin D in the treatment of dermatologic disease.

METHODS

A systematic literature review was conducted via the MEDLINE, Embase, and CENTRAL databases for off-label uses of topical vitamin D analogues in the treatment of dermatologic disease other than psoriasis. The data were synthesized, and evidence-based recommendations were rendered according to the highest level of evidence available.

RESULTS

A total of 165 articles met the inclusion criteria. A moderate to strong recommendation was given for the use of topical vitamin D in combination with corticosteroids and phototherapy in vitiligo and as monotherapy for various ichthyoses, morphea, pityriasis alba, prurigo nodularis, and polymorphous light eruption. There is evidence showing that topical vitamin D is ineffective in the treatment of actinic keratosis, seborrheic keratosis, lichen planus, seborrheic dermatitis, alopecia areata, chemotherapy-induced alopecia, and hypertrophic scars.

CONCLUSION

Topical vitamin D analogues have an important role in the off-label treatment of dermatologic disease, but higher quality studies are still required.