Acne Flashcards
What 3 physiological processes involved in acne?
- INCREASE in sebum excretion rate (SER)
- HYPERCORNIFICATON of the follicular lining leading to obstruction of the pilosebaceous ducts
- COLONISATION with bacterium propionibacterium acnes within the pilosebaceous ducts and subsequent inflammation
What hormones promote sebum production and secretion?
Androgens (e.g. dihydrotestosterone)
What is seborrhoea?
Greasy skin due to increased sebum secretion
Are androgen levels higher in pts with acne?
not usually, it is thought to be receptor hypersensitivity rather than excess hormone in the blood
What occurs in the hypercornification stage of acne?
Occurs at the same time as seborrhoea -
the keratinocyte cells lining these ducts show abnormal differentiation
so that there is hyperkeratosis,
and abnormal shedding.
This leads to retention of the cell lining
and resultant occlusion of the ducts,
forming a microcomedo in affected ducts
What is a microcomedo?
a blocked pore which is the
PRIMARY lesion of acne
In what type of duct does ance occur in?
pilosebaceous duct
What bacteria causes inflammation in acne?
propionibacterium acnes
How does propionibacterium acnes cause inflammation?
Chemotactic and pro-inflammatory mediators diffuse into the surrounding dermis`
What are the two categories of lesions found in acne?
Non-inflammatory lesions
Inflammatory lesions
What are the non-inflammatory lesions found in acne?
Open comedones (blackheads)
Closed comedomes (whiteheads)
Which category of comedomes are more likely to become inflamed and why?
Closed comedones as they are more likely to rupture
What are the inflammatory lesions found in acne?
erythematous papules
pustules
nodules
cysts (rarely)
abscesses (rarely)
Which form of acne do abscesses almost uniquely form in? (starts in adulthood)
acne conglobate (starts in adulthood)
What must all acne conditions begin with?
microcomedo
Name some commoner types of acne?
Acne vulgaris (most common)
Acne cosmetica
Acne medicamentosa (esp. steroids)
What is the advice regarding closed comedones?
Do not pop as will further inflame lesion
Which medications can worse acne?
high progesterone-containing OCP
potent topical or oral steroids
What are the DDx’s for acne? (how can the be differentiated)
rosacea
peri-oral dermatitis
folliculitis
(but there are no comedones in any of these conditions)
What should you investigate in children with acne?
full endocrine evaluation
to exclude an
androgen-secreting tumour of the
adrenals or
ovaries
What are the treatments in acne vulgaris?
Antibacterials - topical
Antiobiotics - oral or topical
Retinoids - oral or topical
Hormone therapy
For how long should acne treatments last (except for what)?
6 weeks (except systemic retinoids e.g. isotretinoin)
What are the two types of topical antibacterial use in acne? (which is more commonly used)
benzoyl peroxide (widely used)
azelaic acid cream (rarely used)
How often should antibacterials be applied in acne? (however what is the problem with this)
twice a day (often not possible as causes irritation)
How do topical antibacterials in acne reduce inflammation?
They have some comedolytic activity, but its main effects is
reducing the number of p.acnes bacteria
and inflammation
What are the benefits of antibacterials?
No problems with resistance
What are the negatives of antibacterials?
Cause local irritation
BPO can bleach clothes
How do topical retinoids work?
They are comedolytic, which means
they remove the surface keratin
- essentially unblocking the pores
and allowing drainage of
microcomedonal contents
What are first line therapy for comedonal acne?
Topical retinoids
What are the risks of topical retinoids?
Still teratogenic even in the topical form and should not be used in breast-feeding or pregnancy
Which antibiotics are used topically?
Erythromycin and
clindamycin
What is a particular problem with topical antibiotics and how is the avoided?
Resistance, thus it is
combined with BPO and
limited to 6 months
For what type of acne is BPO particularly useful?
Papulopustular acne
What are the indications for systemic treatment over topical treatment for acne?
Moderate to severe acne
Failure of topical treatment
Scarring (or marked post-inflammatory hyperpigmentation)
Consider if chest or back involvement
How should a pt transition from topical to oral treatment for acne?
A pt should use topical treatment for acne aswell as systemic
at least 1 topical treatment should be used
What are the 1st and 2nd line systemic antibiotic treatments for acne?
1) Lymecycline (most common)
1) Doxycycline
1) Tetracycline
2) macrolides -> Erythromycin
In whom are cyclines contraindicated? (Why)
pregnancy (tetragenic)
breastfeeding (tetragenic)
children (stains teeth)
What are the benefits and problems with erythromycin?
Benefit - safe in pregnancy
Issue - GI side effects
Issue - staph resistance
For how long should systemic antibiotics be used?
at least 6 weeks
if there is no clinical effect, use
an alternative antibiotic
If you are using topical and systemic antibiotics should you use the same or different antibiotics?
Use the same antibiotics, so bacteria only become resistant to one type of antibiotics
What require monitoring when a pt is on isotretinoin?
FBC
LFTs
Fasting lipids
Pregnancy test
What are the side effects of systemic retinoids?
photosensitivity
teterogenic (contraindicated in breast-feeding and pregnancy)
Depression
Hyperlipidaemia
Deranged liver function
What % of pts who take systemic retinoids will relapse?
About 25%
Who must prescribe systemic retinoids and why?
A dermatologist due to serious side effects
What hormone therapy is used in acne?
cyproterone acetate
known as “Dianette” in the UK
What are the problems with cyproterone acetate ?
variable tolerance
increased risk of venous thromboembolism
Minor acne has what characteristics?
+ papules and pustules
Moderate acne has what characteristics?
+/++ papules and pustules
-/a few small nodules/cysts
+ inflammation
Severe acne has what characteristics?
+++ papules and pustules
mainly small nodules/cysts
++ inflammation
+ scaring
Very severe acne has what characteristics?
+++ papules and pustules
+++ nodules/cysts
+++ inflammation
+ scaring
What is the indication that acne will scar?
Greater inflammation = more scarring
What are possible treatments for acne scarring?
Dermabrasion
Microdermabrasion
Excision
Laser resurfacing
Intralesional steroid for keloid scars
At what stage of acne should scars be treated?
Once acne is no longer active
What are the possible sequelae in acne vulgaris?
Resolution (i.e. no scaring) or
scaring
What are the types of scars that occur in acne vulgaris?
Ice pick scar
Atrophic scar
Keloid/hypertrophic scar
If you have to retreat acne should you change antibiotic?
No assuming it was effective last time, use the same antibiotic
How long should systemic retinoids (isotretinoin) be used for?
4-6mnths
