Dermatology

Question 1

Symmetrical, erythematous, tender nodules on the shin. Heal without scarring

Answer 1

Erythema nodosum

Question 2

Causes of erythema nodosum

Answer 2

Strep infections
Sarcoidosis
IBD
Drugs - penicillins, sulphonamides, COCP

Question 3

Symmetrical, erythematous lesions. Shiny, orange peel skin

Answer 3

Pretibial myxoedema

Question 4

Disease associated with pretibial myxoedema

Answer 4

Graves’ disease

Question 5

Shin lesions which are initially small, red papules. Later deep, red necrotic ulcers

Answer 5

Pyoderma gangrenosum

Question 6

Diseases associated with pyoderma gangrenosum

Answer 6

Idiopathic = 50%
IBD
Connective tissue disorders
Myleoproliferative disorders

Question 7

Causative organisms of eczema herpeticum

Answer 7

Herpes simplex virus-1 = most common
Varicella zoster virus
Usually occurs in people with atopic eczema or dermatitis

Question 8

Presentation of eczema herpeticum

Answer 8

Pre-existing eczema/dermatitis
Widespread, painful, vesicular rash
Systemic symptoms e.g. fever, lethargy, irritability
Lymphadenopathy

Question 9

Management of eczema herpeticum

Answer 9

Viral swabs to confirm diagnosis
Aciclovir - may require IV if severe

Question 10

Antivirals in shingles

Answer 10

Within 72 hours of onset of symptoms
Note: pain may precede rash
Famciclovir or valacycovir –> more likely to reduce postherpetic pain than aciclovir

Question 11

Causative organisms of fungal nail infections

Answer 11

Dermatophytes - around 90%, esp. trichophyton rubrum
Yeasts - e.g. candida
Non-dermatophyte moulds

Question 12

Risk factors for fungal nail infections

Answer 12

Increasing age
Diabetes mellitus
Psoriasis
Repeated nail trauma

Question 13

Management of fungal nail infection - when are topical antifungal treatments used?

Answer 13

Symptomatic e.g. uncomfortable walking
Significant psychological distress
Comorbid conditions
If confirmed cause = dermatophyte or candida –>
- Only very distal, superficial nail involvement
- Supericial white onychomycosis

Question 14

Topical treatment for fungal nails

Answer 14

Amorolfine 5% nail lacquer
Applied 1-2 times daily
6 months for fingernails
9-12 months for toenails

Question 15

Oral antifungal treatment for fungal nail infection

Answer 15

Dermatophyte infection = Oral terbinafine, 2nd line oral itraconazole
Candida/non-dermatophyte = oral itraconazole, 2nd line oral terbinafine

Question 16

What is Koebner phenomenon

Answer 16

Worsening or development of skin lesions at sites of injuries
Seen in vitiligo, lichen planus, psoriasis etc

Question 17

Commonest causative organism of ringworm

Answer 17

Trichophyton

Question 18

Rash of ringworm

Answer 18

Itchy
Erythematous
Scaly
Well-demarcated
Often one or several rings, where edge is more prominent + red and centre is more faint

Question 19

Features of tinea capitis

Answer 19

Can present with well-demarcated hair loss
Itching, dryness + erythema of the scalp

Question 20

Features of onychomycosis

Answer 20

Fungal nail infection –> thickened, discoloured + deformed nails
May spread to skin

Question 20

Features of tinea pedis

Answer 20

White or red, flaky, cracked, itchy patches between toes
Skin may split and bleed
More common when feet are sweaty and damp for prolonged periods