Vitamin D and skin diseases: A review.

Vitamin D, originally associated with rickets and osteomalacia, has recently been shown to have a role in a number of medical and dermatological diseases. It has been found that vitamin D receptors and the enzymatic machinery capable of converting circulating 25-hydroxyvitamin D [25(OH)D] to the active 1,25-hydroxyvitamin D [1,25(OH)D] is present in most cells in the body including the skin. It is well known that vitamin D analogs are effective in the treatment of psoriasis vulgaris because of their anti-proliferative and pro-differentiating effects on keratinocytes. However, new roles have been found for vitamin D in skin, such as immunomodulatory and anti-apoptotic effects thus raising a possibility of its use in conditions such as atopic dermatitis and infections. Increasing evidence now indicates that cutaneous vitamin D synthesis may help in prevention of skin malignancies and further, that cancer mortality may be reduced by oral supplementation of vitamin D. Various epidemiological studies have linked low levels of vitamin D to autoimmune diseases including vitiligo, and topical vitamin D has been used to treat vitiligo. This review focuses on a wide array of roles of vitamin D in various skin disorders with emphasis on both its well-established role as in psoriasis and the less characterized role in other disorders such as ichthyosis, tuberculosis or acne.

Reticulate pigmentary disorders.

Reticulate pigmentary disorders is a term that is loosely defined to include a spectrum of acquired and congenital conditions with different morphologies. The presentations vary from the reticular or net like pattern to the" freckle like" hyper and hypopigmented macules that are usually restricted to the true genetic "reticulate" pigmentary disorders. There is little clarity on this topic and related terms, in major dermatology textbooks. Hence, to harmonize the different entities we feel that the term "mottled pigmentation" could be used to include reticulate pigmentary disorders (acquired and congenital), dyschromasias and the disorders with a reticular pattern. The genetic reticulate pigmentary disorders can also be classified according to the gene loci which in the majority of cases are localized to keratin 5/14. A more useful clinical method of classification is based on the regional distribution, which includes facial, truncal, acral or flexural types. In this review we will largely focus on the inherited reticulate pigmentary disorders.