Acne vulgaris

Dermatology Dr. Hussein A. Al-Sultany
2016-2017
Acne Vulgaris


Definition: it is a self-limited disorder of the pilosebaceous unit, that is seen primarily in adolescents, and appears on skin areas with numerous sebaceous glands.

Epidemiology: nearly all teenagers have some acne (acne vulgaris).
Only about 15-20 % of affected patients need the help of dermatologist.

Natural History and Course:
? The condition usually starts in adolescence (12-14 years) and frequently resolves by the mid-twenties, but 5% of women and 1% of men still need treatment in their thirties or even forties.
? It affects both sexes equally, but the disease tends to be earlier and more persistent in females, and more sever in males.

Etiology and Pathogenesis:

Many factors combine to cause acne (Figure 1), included:
1- Poral occlusion: both genetic and environmental factors (e.g. some cosmetics) can cause poral occlusion, results in the formation of the comedons. Follicles then retain sebum that has an increased concentration of bacteria and free fatty acids. Rupture of these follicles associated with intense dermal inflammation and tissue damage (Figure 2).
2- Sebum excretion: sebaceous glands exist in two forms, either connected to hair follicle (pilosebaceous unit), or exist independently (free sebaceous gland).
Androgens control the sebaceous glands activity and the production of sebum.
These glands, react to maternal androgens for a short time after birth, and then lie dormant until puberty, when the sebum output is increased.
Sebaceous glands are largest and most numerous on the face and upper trunk.
Patient with acne usually has seborrhea (excessive production of the sebum).
3- Bacterial: Propionibacterium acne, a normal skin commensal, is a Gram-positive, anaerobic bacterium, live deep within hair follicles. Elevated production of sebum or blockage of the follicle can cause P. acnes bacteria to grow and multiply.
4- Hormonal: in acne, usually the sebaceous glands respond excessively to a normal level of androgen (increased target organ sensitivity), leading to increased sebum production.
5- Genetic: several studies shown that genetic factors influence susceptibility to acne.
6- Diet: it plays a minor role in the pathogenesis of acne. It is of value only in certain situation in which the patient realizes that some types of foods (as carbohydrates, fatty food, and spices) provoke or exacerbate acne.
7- Emotional stress: can trigger or exacerbate acne vulgaris.