The Sebaceous Gland - Friend or Foe?

Introduction: Sebaceous glands are sebum-secreting components of pilosebaceous units, that play a key role in eccrine emulsification, the impermeability of skin and hair, cytokine, chemokine, interleukin, pheromone, and fatty acid synthesis, acid mantle formation, and hormone production. Although the sebaceous gland has been heavily investigated, many advances in the physiology and pathology of the sebaceous gland have since been identified. Objective: The primary objective of this publication was to perform an updated literature review of the embryology, evolution, structure and function, and pathophysiological disorders associated with the sebaceous gland. Methods: We performed a literature search using PubMed database with keywords sebaceous glands, sebocytes, sebaceous adenoma, sebaceous carcinoma, sebaceous gland hyperplasia, androgenic alopecia, acne vulgaris, and nevus sebaceus, among others. Results: New criteria suggests all patients presenting with sebaceous neoplasms should be screened for Muir-Torr Syndrome (MTS). Germline MMR genetic testing is recommended if colon or endometrial cancers are not present. New research demonstrates that the risk of secondary benign growths of nevus sebaceus remains high, but risk of malignancy is relatively low, and thus surgical excision is not always recommended. In recent years, platelet-rich plasma (PRP) has emerged as a potential new treatment for androgenic alopecia; however, further studies are required to prove PRP efficacious in the treatment of AGA. The Janus kinase/signal transducer (JAK/STAT) signaling pathway, which has been implicated in multiple inflammatory skin conditions, may play a role in the pathogenesis of acne vulgaris. mRNA expression of JAK1 and JAK3 in skin biopsies from acne patients were significantly elevated in comparison to controls (p Conclusions: Sebaceous glands are notable for androgen-regulated; sebum secretion into the infundibular portion of the hair follicle; regulation of cutaneous steroidogenesis, and local androgen synthesis in the pilosebaceous unit and epidermal keratinocytes. They play a critical role in fetal production of vernix caseosa, a lipid-rich substance composed of shed periderm cells and sebum secretions forming around 21 weeks gestation; exhibition of pro- and antiinflammatory properties; synthesis of antimicrobial peptides; neuropeptides, and cytokines; and delivery of antioxidants to the skin. Abnormal sebaceous gland activity has been implicated in a number of medical conditions, including steacystoma simplex and multiplex, sebaceous gland hyperplasia, sebaceoma, sebaceous adenoma, sebaceous carcinoma, nevus sebaceus, and folliculosebaceous cystic hamartoma, acne vulgaris, seborrheic dermatitis, and androgenic alopecia