Acne Flashcards
Acne aetiology
In normal hair follicle:
- Sebaceous gland found just below skin surface
- Glands make sebum (oil)
- Sebum flows to follicle openings
- Pores allow sebum to surface
During puberty there are hormonal changes i.e. increased androgenic hormones which stimulate sebaceous glands
More sebum leads to greasy skin and more acne
Skin at top of pore becomes thicker and dead skin cells shed into pores which form keratin blockage (keratin plug)
Blackheads are due to skin pigmentation, not dirt
How is acne caused?
Trapped sebum provides an ideal environment for Propionibacterium acnes to live and multiply
- Immune response activated leading to inflammation. Skin becomes red.
- Spots become larger and fill with pus (pustules)
- Pustules increase in size and form smaller nodules (cysts)
- Once inflammation is resolved, skin will become discoloured for several months. May cause pitting and scarring.
What makes acne worse?
Progesterone only pills Hormonal changes Picking or squeezing spots Heavy sweating Tight clothing Medicines (Phenytoin, steroid creams) Anabolic steroids
Referral symptoms for acne
Moderate to severe condition
No response to OTC medication after 8 weeks
Acne rosacea
Suspected carcinoma (raised edges)
Benzoyl peroxide
Bactericidal, reduces population of P.acnes in sebaceaous follicles
Available OTC 2.5%-10%
Start with lower dose and titrate up
Clean skin 30 mins before application
Apply to whole affected area not just each spot
SE: Dry skin, irritation, burning sensation
Releases oxygen upon contact to skin so can bleach clothing, bed linen and hair
Course duration around 6 months
If no response after 2 months, consider topical antibacterials
Azelaic acid
Antimicrobial properties
Unplugs blocked pore
Less skin irritation than benzoyl peroxide
Topical antibacterials
Clindamycin gel or erythromycin gel
Bactericidal and reduces inflammation
Requires a prescription
Antibacterial resistance
- Avoid using an antimicrobial (use azelaic acid, benzoyl peroxide)
- Avoid concomitant treatment with oral and topical antimicrobials
- If one antimicrobial is effective, repeat course using same agent
- Do not continue treatment longer than necessary (6months)
Oral antibiotics
1st choice: Oxytetracycline (500mg BD) or tetracycline (500mg BD)
2nd choice: Doxycycline or Lymecycline OD
Use for 3 months, switch if no improvement
Maximum improvement seen between 4-6months
Hormone treatment
Co-cyprindiol For women only Anti-androgen Reduces sebum secretion Take for 3-4 cycles after acne has resolved
Retinoids
Promotes drainage of comedones and inhibits formation of new ones
Reduces sebum secretion
Several months for optimum response
Isotretinoin, adapalene, tretinoin
At first may develop skin redness/peeling which reduces over time
Spots may worsen first before improving
Skin may become more sensitive to sunlight so use at night or use sun protection during the day
SE: Burning, irritation, dryness
Slight risk to unborn babies so should not be pregnant or trying to get pregnant
Isotretinoin
For severe acne which can only be initiated by consultant dermatologist
- Given for 16 weeks
- Monitor LFT’s and lipids regularly
- Causes severe dryness of the skin, mucous membranes, nose bleeds and joint pains
Tetratogenic so not to be given to women of child bearing age unless they are on effective contraception
High risk of causing foetal malformations and increase the risk of spontaneous abortions
Prescription only valid for 7 days – after 7 days prescription is expired and patient should be referred back to the prescriber where another negative pregnancy test is required
Should be a maximum of 30 day supply unless requested by prescriber
Pharmacists cannot accept repeat prescriptions, free sample distribution or faxed prescriptions of isotretinoin
OTC options
Salicylic acid – keratolytic drug with some anti-comedone activity
Nicotinamide – Lowers secretion and reduced inflammation
Benzoyl peroxide
