Acne/Rosacea Flashcards
What are the four pillars of acne pathogenesis?
Follicular epidermal hyperproliferation that leads to excess sebum production, which feeds bacteria causing IL-1 inflammation and cutibacterium acnes overgrowth
What is the regulation of sebum production?
Regulated by androgens (testosterone, DHT) via androgen receptors from keratinocytes at follicle outer root sheath in the sebaceous gland basal layer
What are the contents of sebum?
Triglycerides, wax esters, squalene, cholesterol
What happens to sebum in acne vulgaris?
It acts as a nutrient source for bacteria, which converts triglycerides to free fatty acids
What bacteria that contributes to acne vulgaris is resident flora of follicles?
Cutibacterium acnes
What is the mechanism by which cutibacterium acnes promotes inflammation?
They promote inflammation, leading to antibodies that activate complement, produces lipases, proteases, hyaluronidases, and binds TLR2 to increase pro-inflammatory cytokines (IL1, 8, 12, TNFalpha)
What is this?
Closed comedone
What is this?
Open comedone (black head)
What is this?
Acne papule
What is this?
Acne pustule
What is this?
Acne nodules and cysts
What is this?
Acne sinus tracts
What are possible causes of drug-induced acne?
Dexamethasone, isoniazid
What is the most likely diagnosis?
Polycystic ovary syndrome
What is the most likely diagnosis?
Acne fulminans
What are treatments for acne?
Depends on severity. Mild cases are treated with topical retinoids, most severe cases are treated with oral isotretinoin.
What is benzoyl peroxide used for?
It is an additive antimicrobial that does not allow for a resistance mechanism and is used in addition to oral antibiotics
What is the mechanism of isotretinoin?
Reduced sebum production, decreased androgen synthesis, induces cell cycle arrest, apoptosis in sebocytes
What are hormonal treatment options for acne?
Combination birth control pills that decrease LH and androgen production and spironolactone that is an androgen receptor blocker
Who is most affected by acne rosacea?
Onset after age 30, higher female prevalance (but more severe in men)
What is the pathogenesis of rosacea?
Neurovascular instability and increased reactivity (increased flushing/blushing), abnormalities in TLR2 signaling of innate immunity, inflammation of follicle/surrounding dermis
What molecule is implicated in rosacea symptoms?
Cathelicidins
What is the most likely diagnosis?
Erythematotelangiectatic rosacea
What is the most likely diagnosis?
Papulopustular rosacea
