Arrange the pathophysiological events of acne in the correct sequence.
1. Immune response and inflammation
2. Excessive sebum production
3. Alterations in follicular growth and differentiation Colonization of Propionibacterium acnes
4. Colonization of Propionibacterium acnes
The Correct Answer and Explanation is :
The correct sequence of pathophysiological events in acne is:
- Excessive sebum production
- Alterations in follicular growth and differentiation
- Colonization of Propionibacterium acnes
- Immune response and inflammation
Explanation:
1. Excessive sebum production: Acne begins with the overproduction of sebum (skin oil) in the sebaceous glands. This is often influenced by hormonal changes, particularly during puberty, when androgens increase, stimulating sebaceous glands to produce more sebum. The excess sebum contributes to the formation of clogged pores, also called comedones (whiteheads and blackheads).
2. Alterations in follicular growth and differentiation: The increased sebum production leads to the thickening of the follicular epithelium (the skin lining inside the hair follicles). This abnormal growth and differentiation can cause a blockage in the hair follicle. When the follicular lining is not shed properly, dead skin cells and sebum build up, forming a plug within the follicle, which becomes an ideal environment for bacterial growth.
3. Colonization of Propionibacterium acnes: Propionibacterium acnes (now called Cutibacterium acnes) is a normal bacterium found on the skin, but it thrives in clogged follicles where there is excess sebum. As the bacteria proliferate, they break down sebum into fatty acids, which leads to irritation and inflammation in the surrounding tissue.
4. Immune response and inflammation: The body’s immune system detects the bacterial overgrowth and responds by sending white blood cells to the site. The presence of C. acnes and its metabolic by-products trigger an inflammatory response, leading to the redness, swelling, and pus formation seen in inflammatory acne lesions like papules, pustules, and cysts.
This cascade of events ultimately leads to the clinical manifestations of acne. The severity of acne can vary based on the extent of each stage, particularly how much inflammation occurs and how the immune system reacts.