Interest in sebaceous gland physiology and its diseases is rapidly increasing. We provide a summarized update of the current knowledge of the pathobiology of acne vulgaris and new treatment concepts that have emerged in the last 3 years (2005)(2006)(2007)(2008). We have tried to answer questions arising from the exploration of sebaceous gland biology, hormonal factors, hyperkeratinization, role of bacteria, sebum, nutrition, cytokines and toll-like receptors (TLRs). Sebaceous glands play an important role as active participants in the innate immunity of the skin. They produce neuropeptides, excrete antimicrobial peptides and exhibit characteristics of stem cells. Androgens affect sebocytes and infundibular keratinocytes in a complex manner influencing cellular differentiation, proliferation, lipogenesis and comedogenesis. Retention hyperkeratosis in closed comedones and inflammatory papules is attributable to a disorder of terminal keratinocyte differentiation. Propionibacterium acnes, by acting on TLR-2, may stimulate the secretion of cytokines, such as interleukin (IL)-6 and IL-8 by follicular keratinocytes and IL-8 and -12 in macrophages, giving rise to inflammation. Certain P. acnes species may induce an immunological reaction by stimulating the production of sebocyte and keratinocyte antimicrobial peptides, which play an important role in the innate immunity of the follicle. Qualitative changes of sebum lipids induce alteration of keratinocyte differentiation and induce IL-1 secretion, contributing to the development of follicular hyperkeratosis. High glycemic load food and milk may induce increased tissue levels of 5a-dihydrotestosterone. These new aspects of acne pathogenesis lead to the considerations of possible customized therapeutic regimens. Current research is expected to lead to innovative treatments in the near future. Biology of sebaceous glandsThe sebaceous gland is a holocrine gland, and its secretion is formed by the complete disintegration of the glandular cells. Excreting sebum is the major function of sebaceous glands (1), and increased sebum excretion is a major concurrent event that parallels the development of acne lesions. With the development of human sebaceous gland experimental models for in vitro studies (2-5), considerable progress has been made in our understanding of many new

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Objective-We sought to examine the association between dietary dairy intake and teenaged acne among boys.Methods-This was a prospective cohort study. We studied 4273 boys, members of a prospective cohort study of youths and of lifestyle factors, who reported dietary intake on up to 3 food frequency questionnaires from 1996 to 1998 and teenaged acne in 1999. We computed multivariate prevalence ratios and 95% confidence intervals for acne.Results-After adjusting for age at baseline, height, and energy intake, the multivariate prevalence ratios (95% confidence interval; P value for test of trend) for acne comparing highest (>2 servings/d) with lowest (<1/wk) intake categories in 1996 were 1.16 (1.01, 1.34; 0.77) for total milk, 1.10 (0.94, 1.28; 0.83) for whole/2% milk, 1.17 (0.99, 1.39; 0.08) for low-fat (1%) milk, and 1.19 (1.01, 1.40; 0.02) for skim milk.Limitations-Not all members of the cohort responded to the questionnaire. Acne assessment was by self-report and boys whose symptoms might have been part of an underlying disorder were not excluded. We did not adjust for steroid use and other lifestyle factors that may affect occurrence of acne.Conclusion-We found a positive association between intake of skim milk and acne. This finding suggests that skim milk contains hormonal constituents, or factors that influence endogenous hormones, in sufficient quantities to have biological effects in consumers. Reprints not available from the authors. HHS Public Access Author Manuscript Author ManuscriptAuthor Manuscript Author ManuscriptAcne remains a substantial cause of morbidity and occasional mortality among adolescents and young adults. 1 It is a common, chronic, and self-limiting skin disease that causes physical and psychologic morbidity in up to 90% of adolescents and young adults. 2 In Western countries, it affects all ages, but its maximum prevalence peaks at 16 to 18 years when 75% to 98% of this age group is affected. 2 Even though acne is more common in girls, overall and below the age of 12 years, after 15 years of age it is slightly more common in boys. 3 Acne results from androgen-stimulated hyperkeratinization and obstruction of the pilosebaceous follicles secondary to failure of normal desquamation of the follicular epithelium; androgen-stimulated sebum production; subsequent colonization of the follicles by Propionibacterium acnes and Malassezia species ; and, variably, inflammation. 4 Previous studies have shown an association between dietary intake of milk and prevalence of teenaged acne. Ecological studies suggest an association between Western diet and acne 5 whereas Robinson 6 reported that among 1925 patients who kept a food diary, the majority implicated milk in acne flares. In a previous study of US female nurses who reported their high-school diet and prevalence of physician-diagnosed severe teenaged acne, we found a positive association with intake of total and skim milk. 7 We also found a positive association between milk consumption and prevalence of acne among a prospective co...

Hidradenitis suppurativa (HS) is a chronic, inflammatory, scarring condition involving the intertriginous skin of the axillary, inguinal, inframammary, genital, and perineal areas of the body. It is also referred to as acne inversa and Verneuil disease. Follicular occlusion is the primary event in HS. It is now accepted that the first pathogenetic change is in the pilosebaceous follicular ducts, like acne, and so there has been a move to rename this disorder acne inversa. Despite the legitimate argument that hidradenitis suppurativa is a misnomer, the term has become generally accepted.