1. Acne Vulgaris
TSMU

2. Overview Acne vulgaris is the most common cutaneous disorder.
It affects about 99% of teenagers in industrialized nations..
Patients can experience significant psychological morbidity and, rarely, mortality due to suicide.
affects all races and ethnicities with equal significance.
Darker skinned patients at increased risk for developing post-inflammatory hyper-pigmentation and keloids.

3. Definition
Acne vulgaris, more commonly referred to simply as acne, is a chronic inflammatory disorder of the pilocebaceous unit.
Pathogenesis:
Increased sebum production (androgens)
Abnormal keratosis (androgens)
bacterial proliferation (Propionibacterium acnes)
inflammation

4. Propionibacterium Acne
Propionibacterium acnes is a gram-positive, non-motil rods relatively slow growing typically aerotolerant anaerobic.

5. Pathophysiology
The initial step in the development of acne is the formation of the microcomedon: Follicular keratinocytes that exhibit increased cohesiveness do not shed normally, leading to retention and accumulation of sebum.
Androgens stimulate enlargement of sebaceous glands and increased sebum production, and the abnormal keratinaceo-us material and sebum collect in the microcomedon.
This leads to a build-up of pressure, and whorled lamellar concretions develop. At this stage, a non-inflammatory comedon may be seen clinically.

6. This micro-environment allows the proliferation of bacterium, which is part of the normal flora of follicles. This gram-positive rod has low virulence but is capable of metabolising triglycerides and releasing free fatty acids. This metabolism, as well as its ability to activate complement, produces pro-inflammatory mediators, including neutrophil chemo-attractants. 
With increased pressure and recruitment of inflammatory mediators, the microcomedon may rupture and release immunogenic keratin and sebum, thus stimulating an even greater inflammatory response

8. Clinical Manifestations:
Closed comedone (whitehead) - a clogged follicle. Whiteheads usually appear on the skin as small, round, white bumps.
Open comedone (blackhead) - a plugged follicle that opens and turns dark at the surface of the skin. Blackheads do not indicate the presence of dirt.
Papules - inflamed lesions that appear as small, pink bumps on the skin.
Pustules (pimples) - inflamed pus filled lesions that are red at the base.
Cysts and nodules - large, inflamed, pus filled lesions deep under the skin that can cause pain and scarring.

10. Open comedones (blackhead)
when follicular orifice is opened and distended.
Melanin + packed
keratinocytes + oxidized
lipids  dark colour

11. Whitehead and blackheads

14. Local symptoms :
include pain
tenderness.
Systemic symptoms :
most often absent

15. Classification Comedonal acne: Only comedons
Mild acne: Less than 20 pustules.
Moderate to severe acne: More than 20 pustules

16. Antibiotics:
Topical (clindamycin and erythromycin) and systemic antibiotics used in the treatment of acne vulgaris are directed at Propionibacterium acnes.
Minocycline
Doxycycline (50 t0 200 mg / day for 3 months)
Tetracycline
Lymecycline

17. Retinoids:
These agents decrease the cohesiveness of abnormal hyperproliferative keratinocytes.
Isotretinoin (systemic) mg per kg over 4 to 6 months
Indications?
Tretinoin (topical) cream (0.025%, 0.05%, 0.1%)