Acne Vulgaris Flashcards
When does it usually occur?
80-90% of teenagers (60% of whom seek medical advice)
May persist beyond adolescence- 10-15% of female and 5% of males over 25 being affected
Describe the pathophysiology
Multifactorial
1) follicular hyperkeratinisation -> keratin plugs - made of dead keratinocytes, keratin and melanin.
2) increased sebum production by sebaceous glands (due to increased androgen production) . Contributes to blocking of follicles
3) colonisation by the anaerobic bacterium propionibacterium acnes
4) inflammation
What cause acne (simply put)
Hair follicles (pores) get blocked by particles like dead skin cells or oil
Once blocked, they form raised red bumps on skin
Why is it common among teenagers?
Due to skin changes that occur during puberty
What are the different types of acne?
Mild
Moderate
Severe
How does mild acne present?
Open and closed comedones (blackheads and whiteheads)
The occasional inflammatory lesion
Mainly facial
How does moderate acne present?
Inflammatory lesions - papules and pustules dominate
Face +/- torso
How does severe acne present?
Cysts and nodules
Scarring
Inflammatory papules and pustules
Where are sebaceous glands located?
Dermis of skin
They are connected to hair follicles
Secrete sebum via hair follicle or pores that open directly into skin surface
What is the role of sebum?
Transport nutrients and lubricate skin
Soften hair shaft
Prevent moisture loss
Slightly acidic
What causes an open comedone (blackhead)?
When there is an excessive of sebum or a keratin plug (or both) in hair follicle it can start to fill up the follicle (but not all the way). If it is still open to skin = an open comedone
Why do blackheads look black?
Melanin in keratin plug gets oxidised when exposed to air and becomes dark in colour
Does propionibacterium always live in the hair follicle?
Yes - part of normal skin flora
Why can bacterial overgrowth occur?
If hair follicle gets completely blocked up by sebum and keratin plug = closed comedone - propionibacterium can multiply with no place to go. This results in bacterial overgrowth.
What can the bacterial overgrowth attract?
Immune cells - result of bacteria and immune cells = white pus surrounding red inflammation
= a white head
What genetic and environmental factors can lead to acne?
Hyperkeratosis can have a genetic component
PCOS - increased androgen levels, which leads to more sebum
Psychological stress increases cortisol release - stimulates sebum secretion
Certain moisturisers and cosmetics can block pores
Wearing headband can irritate skin and block pores = contact acne
Excessive face washing - irritate skin surface
Low fat dairy and compounds in chocolate
What is another name for contact acne?
Acne venenata
Where on the body does acne vulgaris typically occur?
Face
Shoulders
Back
Chest
= sites of oil glands
Do most with acne have increased levels of androgens?
No - their sebaceous glands are more sensitive to androgens
How is mild acne treated?
Topical benzoyl peroxide 2.5, 5 or 10% (start with low strength)
OR
Topical retinoid (avoid in pregnancy and breastfeeding) e.g adapalene alone or with benzoyl peroxide
OR
Topical antibiotic e.g clindamycin 1% WITH benzoyl peroxide to prevent antibiotic resistance
OR
Azelaic acid 20%
When treating mild acne how long does it usually take for the effects to be seen?
8 weeks
How do you manage those with moderate acne, not responding to topical treatment?
If response to topical treatment inadequate, add an oral antibiotic - doxycycline, lymecycline, tetracycline, oxytetracycline are first line (erythromycin if pregnant) for max of 3 months
A topical retinoid or benzoyl peroxide should always be co-prescribed with oral antibiotics to reduce risk of resistance
Change to alternative antibiotic if no improvement after 3 months
Alternative to systemic antibiotics in women: COCP (plus topical)
When should a referral to a dermatologist be made?
If not responding to 2 different courses of antibiotics, if they are starting to SCAR
How is severe acne managed?
Isotretinoin - needs specialist prescribing
Marked benefit occurs in nearly all patients (permanent in 65%)
