Sebaceous glands, follicular

Components of pitch and coal tar produce cutaneous photosensitization skin eruptions usually are limited to areas exposed to ultraviolet light. " Most of the phototoxic agents will induce hypermelanosis of the skin if chronic photodermatitis is severe and prolonged, leukoderma may occur." Some oils containing PNAs have been associated with follicular and sebaceous gland changes, which commonly take the form of acne. ... 

Two-year studies were conducted by administering VCD in acetone by dermal application 5 days per week for over 100 weeks to groups of rats of each sex at 0, 15, or 30mg/animal and to groups of mice at 0, 2.5, 5, or lOmg/animal. Acanthosis and sebaceous gland hypertrophy of skin from the scapula were observed at increased incidences in both species. Squamous cell papillomas in male rats and squamous cell carcinomas in males and females were observed in exposed rats at an increased incidence. The combined incidence of basal cell adenomas or carcinomas was also increased in both sexes. Squamous cell carcinomas were found in the exposed mice. Follicular atrophy and tubular hyperplasia of the... 

Sebaceous gland adenomas and carcinomas or basal-cell tumours Follicular-cell adenomas and carcinomas Carcinomas... 

Toxicants can enter the skin through epidermal cells, sebaceous gland cells, or hair follicles. By far the greatest area of the skin is composed of the epidermal cell layer, and most toxicants absorbed through the skin do so through epidermal cells. Despite their much smaller total areas, however, the cells in the follicular walls and in sebaceous glands are much more permeable than epidermal cells. 

Isotretinoin is indicated for the treatment of severe recalcitrant cystic acne. Because of the risks of adverse effects, its use should be reserved for patients who are unresponsive to conventional acne therapies. Treatment should be individu-alixed and modilled depending on the course of the di.sease. The mechanism is believed to involve inhibition of sebaceous gland function and follicular keratinixation. Isotretinoin reduces sebum production, the size of the glantfs. and gland differentiation. 

Deep cystic acne is a complex condition that involves an interaction between hormones (testosterone), sebum, and bacteria. It starts at puberty when the increase in androgen levels causes greater activity of the sebaceous glands. This leads to increased growth of epidermal tissue, which blocks the follicle and creates a comedo (cyst) composed of sebum, keratin, and bacteria. Irritation of the follicular wall follows, with rupture of the follicle and then an acute inflammatory reaction. This leads to an abscess and finally healing with scar tissue. 

Acne vulgaris is a disease of the pilosebaceous unit (i.e., the sebaceous gland and adjacent hair follicle). Sebaceous glands, predominant on the face, chest, and upper back, respond to androgen stimulation. These glands provide sebum to the follicular canal and eventually to the skin surface through the foUicular opening (the pore). Follicular canal contents inclnde keratinocytes, Propionibacterium acnes (P. acnes), and free fatty acids. 

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