Acne

Question 1

What is the aetiology and epidemiology of acne?

Answer 1

Chronic inflammation of pilosebaceous unit
Produce comedones, papules, pustules, cysts and scars
Affects nearly all adolescents in equal distribution between male and female.
Peak age is 18 y/o

Question 2

What is the pathology for acne?

Answer 2

Increased sebum production
Pilosebacous duct hyperkeratosis
Colonisation of duct by propionibacterium acnes
Release of inflammatory mediators (incl. cytokines)
The factors in acne cause comedones, then P. acnes initiate inflammation through chemical mediators including enzymes (lipase, prostaglandins)

Question 3

What are the presenting features of acne?

Answer 3

Comedones:
-black heads:dilated pores with black plugs of melanin containing keratin
-white heads: cream coloured dome shaped papules
Appear at the age of 12 then evolve to become inflamed papules, pustules and cysts
Affects face, back, neck and chest as these have most sebaceous glands
Usually persists until early 20s but can continue into 50s (more in women)
Healing of cysts and abscesses can cause scars (icepicks, boxcar or rolling)
Acne fulminans in adolescents can cause arthritis, vasculitis and fever

Question 4

What are the differential diagnosis of acne?

Answer 4

Acne vulgaris (most common)
Cystic acne
Physical acne (wheelchair, violinist)
Chloracne (from aromatic halogens chemical products)
Conglobate (mass of burrowing abscess and sinuses with scarring)
Acne excoriae (due to squeezing)
Infantile acne
Drug induced
Cosmetic (pomade and cosmetic induced comedonal/papular acne)

Question 5

What are the treatments for acne?

Answer 5

Topical Treatment (BATA)

1. Benzoyl peroxide (acnecide/panoxyl): gel/cream apply 2x daily. Inhibits P. acne growth. May cause irritation and bleach clothing
2. Tretinoin. Retin A cream/gel, may cause irritation but effective in reducing the number of comedones
3. Antibiotics (clindamycin)-mild to moderately severe acne
4. New topical agents (azaleic acid)

Oral Treatment (TART)
1. Tetracyclines (1st line antibiotic)
4 months course, contraindicated in children and pregnancy. May cause candidiasis/photosensitivity
2. Trimethoprim and erythromycin (2nd line treatment)
3. Antiandrogen (dianette)
6-12 months course
Also act as contraceptives, given with oestrogen. Used only in females
4. Retinoid (isotretinoin)
4 months treatment
Reduces sebum secretion, anti-inflmattory, inhibit growth of P. acne.
Used in severe acne or if relapse after antibiotic course.
Very effective, need to monitor LFTs and fasting lipid.
Females need to be on contraceptives 1 month before, during and 1 month after course (contraindicated in pregnancy).
Side effects: hair loss, muscle aches, cracked lips, nose bleeds

Question 6

What are the complication of acne treatment?

Answer 6

Folliculitis (gram -ve) in long term antibiotic treatment