الفهرس 
INTRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Acne vulgaris is a chronic inflammatory disease of the pilo-sebaceous unit,characterized by seborrhea, formation of comedones, erythematous papules, pustules and less frequently nodules, deep pustules and pseudo-cysts. Usually it presents in a sebaceous distribution, where the face is the most often involved while other area such as chest, back and upper arm are involved to lesser extent. It is the Eighth most frequent disease, with 9.4% predominance, including both adults and adolescents of several ethnic groups.Its prevalence can reach 80% and 20% of them have severe acne.
The pathogenesis of acne vulgaris is multi-factorial and the key factor is genetics. Acne develops as a result of inter-play of the following factors: change in the activity of skin micro-flora and P acnes follicular colonization, release of inflammatory mediators into the skin, follicular hyper-keratinization with subsequent follicular plugging, excess sebum production and androgen dependence.
T-helper17 cells are potent inducers of tissue inflammation and increased IL-17 production have been associated with the pathogenesis of infectous & many autoimmune disorders including acne vulgaris.Propioni-bacterium acne induce IL-17 and IFN-γ but not IL-4 in CD4+ T cells. So, P acnes induce both Th17 and Th1 immune responses. In addition, P acnes trigger the expression of key genes involved in Th17 differentiation, including IL-17, IL-17 receptor genes and the transcriptional factorsRORc and RORa. Researches show that IL-17 expressing cells are present in skin biopsies of acne patients and scattered around the dermis near the pilo-sebaceous unit. On the other hand, IL-17 expression is not detectable in skin biopsies from healthy donors. Vitamin D, as an antioxidant agent, have positive impression on acne vulgaris. It seems that vitamin D makes superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) which are found at lower levels in papulo-pustularcases ofacne vulgaris.Also, there is an antibiotic effect for vitamin D and its derivatives which help for infection prevention, too. Also, vitamin D and its derivatives have comedolytic effects.
Popular literature names many triggers of acne vulgaris, especially foods such as nuts,