Dermatology

Question 1

Describe the progression from melanocytic naevi (mole) to nodular melanoma

Answer 1

Melanocytic naevi -> dysplastic melanocytic naevi -> in situ melanoma -> superficial spreading melanoma -> nodular melanoma

Question 2

What is the main cause of all skin cancer?

Answer 2

Sun exposure - UV light

Question 3

What is the treatment for malignant melanoma?

Answer 3

Surgical excision.

Question 4

Give 5 causes of generalised pruritus but no rash

Answer 4

1. AGEING.
2. Chronic renal failure.
3. Cholestasis e.g. PBC.
4. Iron deficiency.
5. Lymphoma.
6. Polycythaemia.
7. Hypothyroid.
8. Drugs

Question 5

Give 3 causes of generalised pruritus with rash

Answer 5

1. Urticaria.
2. Atopic eczema.
3. Psoriasis.
4. Scabies.
5. Lichen planus

Question 6

What investigations might you do in someone with pruritus?

Answer 6

1. FBC.
2. Ferritin levels.
3. U+E.
4. LFT’s.
5. TFT’s

Question 7

What cytokines are commonly targeted in the treatment of pruritus?

Answer 7

IL-4 and IL-13.

Question 8

Why do transdermal drugs need to be lipophilic?

Answer 8

They need to be lipophilic in order to get through the lipid rich stratum corneum

Question 9

Give 2 essential properties of transdermal drugs.

Answer 9

1. Lipophilic.

2. High affinity for their targets.

Question 10

Give 3 advantages of transdermal drug delivery.

Answer 10

1. Avoids first pass effect, hardly metabolised.
2. No pain.
3. Controlled dosing

Question 11

What are emollients used for?

Answer 11

They hydrate the skin and reduce itching

Question 12

In what diseases would the use of emollients be indicated?

Answer 12

Dry skin, eczema

Question 13

What receptors do glucocorticoids target?

Answer 13

Cytoplasmic receptors.

Question 14

How does hydrocortisone work?

Answer 14

Hydrocortisone targets cytoplasmic receptors. It leads to a reduction in pro-inflammatory cytokines and an increase in anti-inflammatories.

Question 15

In what diseases would the use of hydrocortisone be indicated?

Answer 15

Eczema, contact dermatitis

Question 16

Give 3 potential side effects of glucocorticoids.

Answer 16

1. Skin thinning.
2. Oral candidiasis.
3. Acne.
4. Striae.
5. Bruising.

Question 17

What receptors do vitamin A analogues target?

Answer 17

Nuclear retinoic acid receptors.

Question 18

Name a vitamin D analogue

Answer 18

Calcipotriol

Question 19

How does calcipotriol work in the treatment of psoriasis?

Answer 19

Calcipotriol is a vitamin D analogue. It has anti-proliferative and anti-inflammatory effects.

Question 20

In what diseases would the use of calcipotriol be indicated?

Answer 20

Psoriasis.

Question 21

What receptors does tazarotene bind to?

Answer 21

Tazarotene is a Vitamin A analogue. It binds to nuclear retinoic acid receptors.

Question 22

How does tazarotene work in the treatment of acne and psoriasis?

Answer 22

Tazarotene is a Vitamin A analogue. It binds to nuclear retinoic acid receptors and modifies gene expression and inhibits cell proliferation.

Question 23

In what diseases would the use of tazarotene be indicated?

Answer 23

Psoriasis, acne

Question 24

Would you prescribe tazarotene to a pregnant lady?

Answer 24

NO! Tazarotene is highly teratogenic.

Question 25

What class of drug is tacrolimus?

Answer 25

Calcineurin inhibitor

Question 26

When might you prescribe someone tacrolimus?

Answer 26

Tacrolimus is often used as a second line treatment for eczema. (1st line = glucocorticoids e.g. hydrocortisone).

Question 27

Name 3 drug induced dermatological reactions.

Answer 27

1. Exanthematous reactions. 2. Urticaria. 3. Stephen Johnson syndrome.

Question 28

Give 5 signs of eczema.

Answer 28

1. Superficial skin redness/inflammation. 2. Oozing. 3. Scaling. 4. Pruritus. 5. Flexors typically affected e.g. at elbows.

Question 29

Describe the aetiology of eczema.

Answer 29

1. Genetic predisposition - loss of function mutations in filaggrin. 2. Environmental triggers and irritants.

Question 30

Describe the treatment for eczema.

Answer 30

1. Avoid irritants and allergens. 2. Use emollients liberally and frequently. 3. First line - hydrocortisone. 4. Second line - tacrolimus. 5. Third line - sedative anti-histamines.

Question 31

Briefly describe the pathophysiology of acne

Answer 31

Seborrhea (increased sebum production) -> narrowed follicle blocks sebum, comedo formation -> sebum stagnates and p.acne colonises -> inflammation of pilosebaceous unit.

Question 32

Describe the treatment for acne.

Answer 32

Treatment is important to avoid scarring and psychological distress: - Regular washing with acne soaps to remove grease. - Benzoyl peroxide and topical clindamycin. - 2nd line - topical retinoids e.g. tazarotene. - 3rd line - low dose oral antibiotics e.g. doxycycline. - Hormone treatment can also be used

Question 33

What is psoriasis?

Answer 33

A chronic hypo-proliferative disorder characterised by well demarcated silvery grey, scaly plaques over extensor surfaces such as elbows and knees and in the scalp.

Question 34

What environmental factors can cause psoriasis in a genetically susceptible individual?

Answer 34

1. Group A streptococcal infection. 2. Lithium. 3. UV light. 4. Alcohol. 5. Stress.

Question 35

Describe the treatment for psoriasis.

Answer 35

1. Emollients and reassurance. 2. Vitamin D and A analogues e.g. calcipotriol and tazarotene. 3. Phototherapy.

Question 36

What is necrotising fasciitis?

Answer 36

Deep spreading infection of all layers of the skin -> necrosis.

Question 37

Give 3 risk factors for necrotising fasciitis.

Answer 37

1. IVDU. 2. Diabetes mellitus. 3. Homeless. 4. Recent surgery.

Question 38

What bacteria can cause necrotising fasciitis?

Answer 38

1. Type 1: aerobic and anaerobic. | 2. Type 2: group A strep e.g. s.pyogenes.

Question 39

What is the treatment for necrotising fasciitis?

Answer 39

1. Surgical debridement. | 2. Aggressive IV benzylpenicillin and clindamycin.

Question 40

What is cellulitis?

Answer 40

Inflammation of the SC layer of the skin.

Question 41

What bacteria is the commonest causal organism of cellulitis?

Answer 41

S. pyogenes.

Question 42

Give 5 signs of cellulitis.

Answer 42

1. Inflammation. 2. Swelling. 3. Redness. 4. Warmth. 5. Pain. 6. Unilateral.

Question 43

What is the differential diagnosis in someone with the signs and symptoms of cellulitis?

Answer 43

DVT

Question 44

What is the treatment for cellulitis?

Answer 44

Penicillin and flucloxacillin.