Neutrophilic sebaceous adenitis with intralobular Demodex mites: a case report and review of the literature.

A 61-year-old white man presented with a 1-week history of an asymptomatic erythematous, annular plaque with minimal scale limited to the nasal bridge. Histological examination showed a mixed infiltrate of lymphocytes and neutrophils within sebaceous glands. The clinical and histopathological presentation was consistent with a diagnosis of neutrophilic sebaceous adenitis. Several Demodex brevis mites were present deep within the affected sebaceous lobules. Demodex brevis mites are uncommon inhabitants of sebaceous glands of the nose, presenting more commonly on other body sites. The cause of neutrophilic sebaceous adenitis is unknown, but the presence of D. brevis in affected sebaceous glands in this case suggests a possible association.

New pharmaceutical concepts for sebaceous gland diseases: implementing today's pre-clinical data into tomorrow's daily clinical practice.

The human sebaceous gland is a microscopic branched type multiacinar gland been present everywhere on the body except on the palms and soles, whereas they are sparsely located on the dorsum of hands and feet. Several medical conditions are related with sebaceous gland pathology, such as acne, sebaceous hyperplasia, sebaceous adenoma and sebaceous carcinoma. Acne is a common, complex, chronic disorder of the human pilosebaceous unit that mostly occurs in adolescence and young adulthood. The sebaceous gland plays an exquisite role in the initiation of the disease. The multifactorial nature of the pathogenesis of acne includes increased sebum production, alteration of the quality of sebum lipids, inflammatory processes, interaction with neuropeptides and dysregulation of the hormone microenvironment, follicular hyperkeratinization and inflammation maintained by Propionbacterium acnes products within the follicle. On the other hand, the sebaceous gland, as a major and critical compartment of human skin, is also affected through ageing, both intrinsic and extrinsic, which lead to distinct clinical and histological changes. Intrinsic ageing of the sebaceous gland is determined primarily by genetic factors and hormonal status, with androgens playing a major role. A clinical manifestation associated with intrinsic ageing changes is skin xerosis. Extrinsic ageing of human sebaceous gland is mainly caused by accumulating UV irradiation, especially UVA. Photoageing of sebaceous gland is expressed with a wide spectrum of benign and malignant sebaceous tumours, such as sebaceous hyperplasia, sebaceous carcinoma and Muir-Torre syndrome. This review will focus on the pathogenesis of the most common sebaceous gland diseases and their molecular pathways which may represent future pharmaceutical targets.