Final answer:
Acne vulgaris involves sebaceous glands, hair follicles clogged with sebum and keratin, and inflammation caused by Propionibacterium acnes. The condition manifests as non-inflammatory comedones and can progress to inflammatory lesions. Treatment options range based on severity.
Step-by-step explanation:
Acne vulgaris is a common skin condition that primarily affects areas rich in sebaceous glands, such as the face and back. The condition is related to hair follicles clogged by an overproduction of sebum and keratin, resulting in non-inflammatory lesions known as comedones. Comedones may develop into whiteheads or blackheads; the latter appear dark due to lipid oxidation when exposed to air. The role of the bacterium Propionibacterium acnes is crucial in acne pathogenesis. It infects the clogged hair follicles, leading to inflammatory lesions such as papules, pustules, nodules, or cysts. Treatment for acne varies from topical agents to antibiotics, and severe cases may require medications such as isotretinoin or phototherapy.