Acne Vulgaris Flashcards
What is acne vulgaris?
Common disorder of the pilosebaceous unit primarily seen in adolescents.
What is the most notable factor that affects acne?
Testosterone
What are the lamellar granules?
Oil synthesizing cells that form protective layer to protect against infection
What do melanocytes do?
Form pigment
What are merkel cells?
Sensory cells that respond to touch; connected to sensory neuron
What does the epidermis extend into?
Hair follicle
Within what unit does acne occur?
Pilosebaceous unit
What are the four key elements of pathogenesis in acne vulgaris?
- Follicular epidermal hyperproliferation
- Sebum production
- Presence and activity of Propionibacterium acnes/Cutibacterium acnes
- Inflammation and immune response
What are the clinical features of acne?
- Comedones (clogged pores)
- Papules
- Pustules
- Nodules on face, chest, and back
What type of comedome is a blackhead?
Open
What type of comedome is a whitehead?
Closed
What is important to know about pustules?
Infection involved
What is important to know about cysts?
Bacterial growth and tissue erosion
Name the steps of progression to a pimple
- Microcomedone
- Comedone
- Inflammatory papule or pustule
- Nodule
What are noteworthy features about the microcomedone?
- Hyperkeratotic infundibulum (by the opening)
- Sebum secretion
What are noteworthy features about the comedone?
- Accumulation of shed corneocytes and sebum
- Dilation of follicular ostium
What are noteworthy features about the inflammatory papule or pustule?
- Further expansion of follicular unit
- Proliferation of Propionibacterium acnes
- Perifollicular inflammation
What are noteworthy features about the nodule?
- Rupture of follicular wall
- Marked perifollicular inflammation
- Scarring caused by erosion of tissue
What is something that regulates follicular keratinocyte proliferation?
Linoleic acid (essential fatty acid in the skin) - low levels can induce follicular keratinocyte hyperproliferation and the production of proinflammatory cytokines
Are linoleic acid levels decreased, increased, or normal in patients with acne?
Decreased
When do linoleic acid levels normalize in patients with acne?
After successful treatment with isotretinoin (vitamin A derivative, linoleic acid)
What hormones are significant promotors of cell proliferation, hyperkeratinization, sebum, and acne?
Androgens (testosterone and DHEA)
What does DHEA stand for?
Dehydroepiandrosterone
What stimulates the ovary to make androstenedione (which can then be made into testosterone or estrogen)?
FSH and LH
What stimulates the adrenal gland (which can eventually make testosterone or DHEA)?
ACTH
What are the pharmacologic mechanisms for acne treatment?
- Reduce inflammation
- Reduce cell proliferation/cohesion (sticks to itself)/keratinization
- Reduce sebum production
- Reduce bacterial population
What type of agent is benzoyl peroxide?
Topical
What does benzoyl peroxide do?
- Generates reactive oxygen species, which bombards bacteria with electrons and can be bacteriocidal (unpaired electron is bacteriocidal!)
*Dissolves keratin, opens pores, and allows sebum to drain
How is benzoyl peroxide used?
Used in combination with antibiotics and with adapalene (retinoid - this is the only retinoid it can be used with)
What is an alternative use for benzoyl peroxide?
BPO is a bleach! Can be used as a teeth whitener
What is azelaic acid?
Dicarboxylic acid (produced by plants following a wound); white powder component of a cream
What does azelaic acid treat?
- Acne
- Rosacea
- Skin spots
What is the MOA of azelaic acid?
Unknown! What we do know:
* Antibacterial activity, maybe by inhibiting protein synthesis
* Inhibits keratin synthesis
* Inhibits tyrosinase enzyme necessary for skin pigment
* Inhibits a hyperactive protease activity that converts cathelicidin into antimicrobial skin peptide LL-37
What is salicylic acid’s MOA?
Inhibits cyclooxygenase-1 (COX-1); plant derivative
What does salicylic acid do?
Facilitates the sloughing of skin cells which helps open pores
Which drugs are considered retinoids?
- Tretinoin
- Isotretinoin
- Adapalene
- Tazarotene (Avage)
- Trifarotene (Aklief)
Which retinoid is also known as a “all-trans retinoic acid” (atra)?
Tretinoin (1st gen product)
Which retinoid is a 13-cis retinoic acid?
Isotretinoin (1st gen, carbon in different position)
Which retinoids are 3rd generation?
Adapalene and tazarotene
Which retinoid is tolerant to benzoyl peroxide?
Adapalene (can be used in combination with benzoyl peroxide!)
Which retinoid is 4th generation?
Trifarotene
What does further generations of retinoids mean?
Later in generations = more specific more retinoid receptors that are for acne
Several signal transduction pathways converge on what?
CBP p300
What does CBP p300 lead to?
Alterations in gene expression (which ones are changed depends on the cell)
Which group is retinoic acid a part of?
Group I Hormones -> retinoic acid -> nuclear receptors -> CBP p300 -> alterations in gene expression
What does a canonical retinoic acid receptor (RAR) signaling mean?
Ordinary
What does a non-canonical retinoic acid receptor (RAR) signaling mean?
Not so ordinary
What can RARs combine and form a dimer with?
Retinoic X receptor
As dimers, what can RAR/RXR do?
Regulate retinoic acid response elements (RARE), which activate the transcription of certain genes depending on the subtypes
What are the three subtypes of RARs?
Alpha, beta, and gamma (they are no uniformly spread across each cell type)
What are the desired targets in treating acne?
RAR-gamma receptors (these are the RAR subtypes predominant in skin cells)
What are the effects of retinoids?
- Decrease cell differentiation and proliferation
- Decrease sebum production
- Result in dry, scaly skin, redness, and irritation
- Other side effects if taken orally
What acne drug class is contraindicated in pregnancy?
Retinoids - teratogenic! Interfere with fetal organ development, and must sign iPledge program
What is the oral form of isotretinoin approved for?
Treatment of recalcitrant and nodular ance vulgaris
How is the efficacy of isotretinoin’s oral form?
Remarkable efficacy in severe acne and may induce prolonged remissions after a single course of therapy
When are clinical effects generally noted with isotretinoin?
1-3 months after starting therapy
How many patients relapse with isotretinoin?
One third of patients, typically within 3 years of stopping therapy
What are some toxic systemic side effects of isotretinoin?
- Altered plasma lipids
- Liver damage
- Premature closure of epiphyseal plate = short stature and other bone abnormalities
What are some common side effects of isotretinoin?
- Dry skin
- Dry eye
- Nose bleed
- Muscle pain
- Reduced visual accuity
What are some characteristics of tretinoin?
- Topical retinoid
- Legacy product (used to use, not really anymore, cheap)
- Not photo-stable, so must be used at night!
- Not stable with BPO (new formulation is being with BPO is being worked on)
What concentration of adalapene is OTC?
0.1%
What concentration of adalapene is with BPO?
0.3%
What is adalapene considered?
“Workhorse”
How efficacious is tazarotene topical?
Potent and efficacious compared to tretinoin, but not as well tolerated at the usual dose
What is something significant about trifarotene?
4th generation = high specificity for the RAR-gamma receptor, which is found predominantly in the skin cells. Therefore, very low concentration is used (0.005%)
Which oral tetracyclines can be used to treat acne?
Minocycline, doxycycline, and sarecycline (Seysara)
Which oral tetracycline is approved in ages 9 and older?
Sarecycline (Seysara)
What form of erythromycin and clindamycin can be used to treat acne?
Cream with BPO
What is erythromycin and clindamycin’s MOA?
Attaches to ribosome and prevents it from moving (translocation); protein synthesis inhibitor, used less due to resistance
What form of sulfacetamide-sulfur can be used to treat acne?
Topical
What is sulfacetamide-sulfur’s MOA?
Inhibits dihydropteroate synthase
What form of Bactrim can be used to treat acne?
Oral
What form of dapsone can be used to treat acne?
Gel
What is dapsone’s MOA?
Inhibits dihydropteroate synthase; PABA agonist = same MOA as sulfa drugs
What form of minocycline (Amzeeq) can be used for acne?
Foam
How can birth control pills help control acne?
Reduce androgen production
What is flutamide’s MOA?
Blocks testosterone receptors (primary use is in prostate cancer)
What does flutamide have a boxed warning for?
Liver damage
What is spironolactone’s MOA?
K-sparing diuretic, also blocks androgen receptors
What is clascoterone (Winlevi)’s MOA?
Blocks testosterone receptors
Why are flutamide and spironolactone not used in men?
Inhibits secondary sexual characteristics
Is clascoterone (Winlevi) ok for males?
Yes
What form does clascoterone (Winlevi) come in?
Cream