What are the 3 types of pilosebaceous units?
- Terminal follicles
- Vellus follicles
- Sebaceous follicles
What type of hair are terminal follicles associated with?
Associated with long hairs (ie scalp)
What type of hair are vellus follicles associated with?
with miniature hairs like arm hairs
What type of hair are sebaceous follicles associated with?
no visible hair shaft! mostly on the face
What are the 3 main “sebaceous” areas
face, upper chest, upper back
What is the composition of sebum?
- triglycerides
- squalene (long chain FA precursors of cholesterol)
- Cholesterol and cholesterol esters
- wax esters
- some IgA secretion
What is the physiological function of sebum?
No precisely known function in humans!
Could potentially be hydration, antimicrobial or anti-oxidant
What are 2 regulators of sebum production? What are their effects?
- Androgens: increase sebum production
2. Retinoids: inhibit sebum production and trigger sebocyte apoptosis
Define: Acne vulgaris
Chronic inflammation of the pilosebaceous unit that is associated with comedones
- primarily affects adolescents but can persist well into adulthood
What are comedones?
blocked folllicular ostium with dead keratinocytes and sebum
What are the 4 main steps in the pathogenesis of Acne?
- Abnormal follicular keratinization
- Increased sebum production
- Overgrowth of follicular bacterium
- generally propionibacterium acnes - Inflammation
What are some medications that can exacerbate acne?
- corticosteroids
- Lithium
- Barbituate anticonvulsants
- EGFR inhibitors
What types of lesions are common in mild acne
mostly comedones with few inflammatory lesions
No nodules
Minimal to no scarring
What are the 3 therapy approaches for mild acne?
- Reduction in comedones: topical retinoids or benzoyl peroxide
- Reducing sebum production: topical retinoids
- Reducing bacterial growth and inflammation: topical clindamycin or erythromycin combined with benzoyl peroxide, topical azelaic acid, topical retinoids + benzoyl peroxide, topical dapsone
How do topical retinoids work?
- reduce comedones by promoting keratinocyte desquamation
- Reduce sebum production
- have anti-inflammatory properties
How long do you need to treat mild acne with retinoids ?
weeks to months to see an effect
What are 3 adverse effects from treatment with retinoids?
- Redness
- Desquamation
- Burning sensation
How do topical antibiotics work to treat mild acne? What should be used as a combined treatment?
Overall reduction in p. acnes populations
Should use in combination with benzoyl peroxide to decrease resistance
What is the mechanism of action of topical azelaic acid?
- antibacterial
- promotes keratinocyte desquamation
- Decreases hyperpigmentation
What are some adverse effects of treatment with Azelaic acid?
- redness
- desquamation
- burning sensation
What are the 4 treatment categories for managing moderate acne?
- Systemic antibiotics
- Systemic hormonal therapies
- Systemic isoretinoin
- Intra-lesional steroid injections
What is the first choice for antibiotic therapy for moderate acne?
One of: tetracycline/doxycycline/Minocycline
What are some side effects to systemic antibiotic treatment for moderate acne?
- takes several months to achieve clinical results
- GI upset
- rash/hepatitis
- phototoxicity
- hyperpigmentation
- benign intracranial hypertension
What are 3 examples of oral hormonal therapies you could use for managing moderate acne?
- Diane 35: low dose estrogen + cyproterone acetate
- Ortho tricyclen/Alesse: low dose estrogen + a 3rd gen progestin (has minimal androgenic activity)
- Spironolactone 50-100 mg
- anti-androgen (but also a diuretic)
What is the most effective therapy for severe acne?
Systemic isoretinoin
How does systemic isoretinoin work to treat severe acne?
Inhibits sebum production and causes atrophy of sebaceous glands
What are the remission rates for severe acne after a 6 month course of isoretinoin?
about 60-80%
What are the side effects of isoretinoin therapy?
- severe teratogen: pregnancy prevention essential from 1 month prior to therapy, during therapy, and 1 month following
- dry skin/nasal mucosa/lips
- Dermatitis
- photosensitivity and decreased light vision
- Elevated liver function tests and hyper-triglyceridemia
- Alopecia
- Depressive symptoms and suicidal risks
what are the indications for treatment with systemic isoretinoin therapy?
- nodulo-cystic acne
- scarring acne
- refractory moderate acne
What are contraindications to isotretinoin therapy?
Pregnancy/breastfeeding
not compliant with pregnancy prevention
Concominant tetracycline therapy
- risk of intracranial HTN
Depression if uncontrolled
Define rosacea
a chronic inflammatory and vaso-dilatory skin disorder characterized by facial flushing and erythema
What is the epidemiology of rosacea?
1.4 million Canadians are affected
more common in women than in men
More common in caucasians
What are some known triggers of rosacea?
- UV light
- Temperature shifts
- Topical steroids
- Alcohol consumption
- Cosmetics/irritants
What are two pathological findings common in rosacea?
- dilated capillaries
2. Perifollicular inflammation
What are the 4 subtypes of rosacea?
- erythematotelangiectatic rosacea (ETR)
- Papulopustular rosacea (PPR)
- Phymatous rosacea (PR)
- Ocular rosacea (OR)
What are defining features of erythematotelangiectatic rosacea (ETR)?
- dilated capilaries
2. fixed facial erythema
What are defining features of papulopustular rosacea (PPR)?
- central facial erythema
- pustules
- papules
- fixed edema
* 5. no comedones! (different from acne)
What is the pathological feature of phymatous rosacea?
hypertrophic changes of protruding structures
What are defining features of ocular rosacea ?
- foreign body sensation
- Burning or stinging/dryness/itching
- Photophobia
- Conjuctival telangiectasia
- Peri-ocular erythema
What specific treatment options are available for the treatment of ETR
- erythema
- laser or intense pulsed light therapies work OK
- topical brominidine 0.33% gel acts as an alpha 2 agonist - Telangiectasia
- vascular laser surgery is #1 or alternative is intense pulsed light
What therapies are available for papulo-pustular rosacea?
- Topical
- topical metronidazole (0.75-1%)
- topical azelaic acid - Oral therapies
- oral tetracyclines
- oral isotretinoin (0.5mg/kg/day)
What are the indications of use for topical metronidazole?
only moderately effective for inflammatory papules, minimally effective for erythema, and not effective for telangiectasia
What is a significant side effect to topical metronidazole
skin peeling and erythema
What are the available treatment options for phymatous rosacea?
- oral tetracyclines
- Oral isotretinoin
- Surgical reconstruction
- co2 laser
- reconstructive plastic surgery
What are the available treatment options for ocular rosacea?
- topical steroid solutions
2. oral tetracyclines