Draw and label a simple pilosebaceous unit?
Note: the oil sebum is secreted by the sebaceous ducts and acts an emollient for the skin
Describe the 4 step pathogenesis of acne?
- Increase sebum excretion rate from the sebaceous glands (affected by androgen)
- Hypercornification of the follicular lining leading to obstruction of the pilosebaceous ducts. This forms a microcomedo (blocked pore)
- Colonisation of Propionbacterium acnes. This is normal a commensal microbe, but which proliferates in a sebum rich environment
- Inflammation
Which hormones are sebum associated with?
Androgens: reason for increased incidence of acne at puberty in line with increased levels of androgens.
What is seborrhoea?
Oily skin due to excess sebum production
What does the following picture show.
Open Comodone aka blackhead
Distended pilosebaceous unit which is impacted with keratin and lipids.
Describe and name the following image and state the key features?
Closed comones (whiteheads)
Pale slightly evelvated small papules.
More likely to become imflamed as the follicles can burst more easily.
When do pustules and papules form in acne and how long do they last for?
Superficial inflammatory lesions.
They form when a closed comodone bursts releasing irritant FFA (Free Fatty Acids) in to the surrounding dermis.
Last 1-2 weeks.
Describe the features of nodules in acne, symptoms, time span?
Nodules occur when there is an excessive inflammatory response in the surrounding dermis.
They are painful and last a few weeks to months.
When would you see cysts and abcesses in acne?
True cysts are very rare in acne.
Abcesses are unique to acne conglobata an acne which tends to start in adult life.
What is the potential acne sequale in those who do not have scarring?
After the inflammatory lesions of acne settle patients may have:
- Erythematous macules.
- Hyper/hypo pigmeneted macules.
What are the different scars which can form in acne?
- Ice pick
- Atrophic
- Hypertrophic/ keloid
Usually occur after the larger inflammatory lesions settled, aka deep pustules, papules or cysts.
Which factors may aggravate acne?
- Greasy cosmetics and hair products
- Heat and humidity
- Excessive washing
- Manipulation of lesions
- Exogenous medications
What is the 1st line treatment in mild to moderate acne?
Topical treatments:
- Benzoyl peroxide (BPO)
- Retinoids (tretinoin, Adapalene)
- Antibiotics - erthromycin, clindamycin
Should be applied twice a day
Describe the key features of topical retinoids, what they are, how they help acne, side effects?
- Vitamin A derivatives
- Comedolytic (remove surface keratin, unblocking the pores and allowing the drainage of microcomodomes) - exfoliating
- Should be used in comodomal acne.
Side effects:
- Teratogenic
- Erythema and irrittaion/stinging
- Photosensitivity
Name and describe the key features of topical antibacterials, what they are, how they help acne, side effects?
Benzoyl Peroxide and Azelaic Acid
Work by reducing the number of P. acne bacteria.
Side effects incluide dryness and irritaition
Indicated for mild-moderately severe papulopustular acne
Describe the key features of topical antibiotics, what they are, how they help acne, side effects?
- Anti microbial and anti inflammatory effect
- Erythromycin or Clindamycin
- Can be combined withe Benzoyl Peroxide: Benzomycin or Duac
- Problems:
- Antibiotic resistance, don’t use for more than 6 months
- Indicated for mild - moderately severe papulopustular acne
What are the inidications for starting systemic antibiotics in acne?
Moderate to severe acne
Failure of topical treatments
Involvement of the chest or back
Presence of scarring or marked post inlfammtory hyperpigmentation.
What are the different systemic antiobiotics used to treat acne?
- 1st Line:
- Tetracylines: Lymecyclin or Doxycycline or tetracycline
- Not for children <12 or to women trying to conceive
- 2nd Line:
- Macrolides - erythromycin
- 3rd Line:
- Trimethoprim
- Not licenced
Note biggest issue is resistance: paticularly seen with erythromycin and staph
What are the hormanal treatments used for acne, and who are they indicated for?
Dianette: (OCP)
- an Oral contraceptive which contains oestrogen and anti androgen.
- It is indiated for females patients with moderate to severe patinets who have failed to respond to systemic antibiotics.
- Contraindicated in those at risk of DVT and pregnant ladies or those breast feeeding.
cyproterone acetate:
- Anti androgen
- Same indications and side effects as dianette
What are the systemic retinoids which are used, and what is the indication?
- Isotretinonin (oral retinoid)
- Severe acne
- Active acne with scarring
- Resistant disease
- Acne which rapidly reoccurs on the cessation of antibiotics
- Acne causing psychological distress
What are the important point when prescribing isotretinoin, what are the main side effects and what are the baseline investogations you should do?
Highly teratogenic, women of child bearing age should be on 2 forms of contraception.
Increased lipids
Deranged LFTs
Arthralgia/myalgia
Dry mucosa and skin
Epistaxis
Ix:
Pregnancy test
LFTs - transaminases (hepatitis)
U/E’s
Lipids (triglyceride and cholesterol levels . . .. hypertriglyceridoema can cause pancreatitis)
FBC - anaemia and thromboxytopeni
Name some treatments for scarring?
Microdermabarsion
Demabrasion
Laser resurfacing (risk of hyperpigmentation)
Intralesional steroids for keloid scars
Name 3 types of acne including the most common form?
Acne vulgaris (most common)
Acne conglobata (abcsesses)
Acen fulminans
Clinical features of acne rosacea?
- Papules
- Pustules
- Nodules/cysts
- Flushing + persistent redness
- telangiectasia
- Rhinophyma - big, fleshy nose (due to hypertrophy of sebaceous glands
NO COMEDONES - more common in older people
