Acne

Question 1

What are the two types of acneiform eruptions?

Answer 1

Acne Vulgaris

Acne Rosacea

Question 2

Describe the pathophysiology of acne vulgaris

Answer 2

Disease of the pilo-sebaceous unit (PSU)
Combination of increased stickiness of keratinocytes and increased sebum viscosity measns that keratinocytes aren’t shed properly and form a plug which blocks the hair follicle.
The change in keratinocytes and sebum cause a change in commensal bacterial behaviour which causes inflammation.

Question 3

What types of skin lesions may be present in acne vulgaris? What determines the type of lesion(s) that form?

Answer 3

Depends on inflammation
Papules, pustules, nodules, cysts
Can eventually form scars

Question 4

Which bacteria is involved in acne vulgaris?

Answer 4

Propionobacterium acnes

- anaerobic, gram-positive rod

Question 5

Which keratinocytes are mitotically active?

Answer 5

Basal keratinocytes

Question 6

What is a comedo?

Answer 6

Blocked hair follicle - formed by unshed keratinocytes

Question 7

What is the pilo-sebaceous unit? Where are they most prevalent?

Answer 7

Units made up of the hair follicle, sebaceous gland and erector piniae muscle
Most prevalent on the face, chest and back

Question 8

Describe the two types of commodone

Answer 8

Open; keratinocyte plug is visible. Appears black (“blackhead”) due to the melanin present in the dead keratinocytes.
Closed; skin closes over the top of the comedo

Question 9

Describe the topical treatment options for acne vulgaris

Answer 9

Retinoids (vitamin A derivatives) - e.g. Isotretinoin
- anticomodonal; reduces stickiness of keratinocytes
Benzoyl peroxide (BPO)
- oxidising agent; anti-inflammatory and antibacterial
Topical antibiotics
- clindamycin
- tetracycline
- erythromycin
——-> should not be used on their own, due to risk of resistance (use with BPO at least)

Question 10

Describe the non-topical treatment options for acne vulgaris

Answer 10

Oral antibiotics

• tetracyclines (NOT children or pregnant women)
• erythromycin
• (trimethoprim)

Anti-androgens

• oral contraceptives
• Dianette

Oral isotretinoin
- stubborn acne only, very effective

Question 11

Describe the disadvantages of isotretinoin

Answer 11

Highly teratogenic when taken orally

• centrofacial malformations, cardiac and large vessel malformations
• must have a negative pregnancy test before starting

Many potential side effects
- Hair loss, mood swings, depression, abnormal LFTs, hypertriglyceridaemia

Commonly causes dry skin

Very expensive

Question 12

What type of drug is isotretinoin?

Answer 12

Retinoid; vitamin A derivative

Can be administered topically and/or orally

Question 13

What is acne rosacea?

Answer 13

Chronic inflammation of the PSU and cutaneous vasculature

Question 14

Describe the classic distribution of acne rosacea

Answer 14

“Ace of clubs” distrubution; nose, cheeks and forehead but spares the periorbital areas
Rarely occurs on non-facial areas of skin

Question 15

Which skin types are more prone to acne rosacea?

Answer 15

Fair skin types (i.e. 1 and 2)

Question 16

List the four subtypes of acne rosacea

Answer 16

Erythemato-telangiectatic
Papulo-pustular
Phymatous - soft tissue hyperplasia, esp. nose
Ocular - altered tear film, causes dry gritty eyes

Question 17

Which type of acne has a much much higher incidence in males than females?

Answer 17

Phymatous acne rosacea

Question 18

Describe the topical treatment options for acne rosacea

Answer 18

Topical antibiotics - metronidazole
Azelic acid
Ivermectin
Brimonidine (vasoconstrictor)

Question 19

Describe the non-topical treatment options for acne rosacea

Answer 19

Oral antibiotics - tetracycines, erythromycin, metronidazole
Isotretinoin (used less often than in acne though)
Light-based treatments (used more often than for acne)

Question 20

Describe the role of light-based treatments in the management of acne rosacea

Answer 20

Light treats background telangectasia and erythema

Long-term benefits (effects can last 5-10 years)

Question 21

List five less common types of acne

Answer 21

Infantile acne
Acne conglobata
Acne fulminans
Pyoderma faciale
Acne inversa