Dermatology

Question 1

Medical student suddenly develops a spotty teardrop-shaped rash over his chest and arms 6wks after strep throat. Improves with phototherapy.
Every time he gets a strep throat thereafter however, he again gets the rash. His GP thus gives early antibiotics whenever he gets tonsillitis.

Answer 1

Guttate psoriasis

Question 2

Round, coin-shaped circles of very itchy, red skin. No central clearing. Weepy and crusts, gets infected easily.

Answer 2

Discoid eczema

Question 3

8yo boy with hayfever and asthma gets itchy crook of elbow and behind the knee. As a baby he had the same thing on his face.

Answer 3

Atopic eczema

Question 4

Man has to stop wearing Levi jeans because he gets an itchy area where the metal button touches his abdomen. Patch testing confirms nickel is the culprit.

Answer 4

Allergic dermatitis (type 4 hypersensitivity reaction)

Question 5

Hairdresser gets very itchy, red fingers after a day of shampooing models’ hair in preparation for a shoot.

Answer 5

Irritant (contact) dermatitis

Question 6

Bored office worker sits at desk all day mindlessly itching the side of his knee. Notices that the area is now red with little lines all over it.

Answer 6

Lichen simplex

Question 7

Elderly man with scaly irregular dry skin around his ankles. Looks like crazy paving.

Answer 7

Asteototic eczema

Question 8

Overweight lady with champagne bottle legs, skin over shins feels hard to touch, has irregular painless ulcer over medial maleolus. Whole area is “very itchy”.

Answer 8

Varicose eczema

Question 9

24yo man with itchy fluid-filled vesicles on his hands and soles of his feet

Answer 9

Pompholyx eczema

Question 10

17yo concerned by little bumps on forehead

Answer 10

Comedonal acne

Question 11

40yo man complains of easy flushing, pustules, papules, redness, broken capillaries on face. No comodones. Notices that his nose is “getting bigger” too.

Answer 11

Rosacea

Question 12

Teen with combination of pus-filled and just raised bumps over his cheeks, forehead and chin. Red and inflamed.

Answer 12

Papulo-pustular acne

Question 13

Teen with large, erythematous, raised, tender lesions over the face. Very disfiguring.

Answer 13

Nodulo-cystic acne

Question 14

“Ace of Clubs” sign

Answer 14

Rosacea (forehead, cheeks)

Question 15

Deep red patches in axilla and groin. No scale. You thought it was tinea, but anti-fungal didn’t work

Answer 15

Flexural psoriasis

Question 16

Man taking doxycycline for a sore throat gets red, itchy rash on arm after being in the sun. Rash stops exactly where his sleeve starts

Answer 16

Photoallergic dermatitis

Question 17

Where does psoriasis affect?

Answer 17

Scalp, elbows, bellybutton, lower back and buttocks, knees, NAILS. Spares the face.

Question 18

52yo university lecturer with itchy red rash on cheeks, sides of nose (butterfly-shaped), eyebrows, chest and scalp.

Answer 18

Seborrhoeic dermatitis

Question 19

Treatment for mild comedonal acne?

Answer 19

Topical retinoid

Question 20

21yo man complains of burning, painful, pus-filled spots on his hands and feet. Some brown macules around them too. You swab them, but to they grow nothing (they’re sterile)

Answer 20

Pustular psoriasis

Question 21

Three cardinal signs of psoriatic nails

Answer 21

Thickening
Pitting
Onycholysis

Question 22

Koebner phenomenon?

Answer 22

In psoriasis: scratching normal skin causes a psoriatic plaque to appear.

Question 23

What’s the difference between a plaque and a macule (or patch)?

Answer 23

A plaque is RAISED. You could feel on with your eyes shut. Macules and patched are flat.

Question 24

Does sunlight make psoriasis better or worse?

Answer 24

Better. This is why psoriasis spares the face (too much sun, psoriasis doesn’t like it)

Question 25

Usually, is psoriasis itchy?

Answer 25

No.

Question 26

What are 2 bugs that can infect an area of eczema?

Answer 26

``` Staph aureus ("impetigenisation". Oral fluclox) Herpes simplex ("eczema herpeticum". Serious, admit to hospital) ```

Question 27

What's best for eczema: creams or ointments of topical steroids?

Answer 27

Ointments (messier, but more effective since they moisturise too). Creams do not moisturise.

Question 28

Pathophysiology of atopic eczema?

Answer 28

Mutation in filaggrin gene leads to dry skin caused by decrease of fatty acids in the epidermis

Question 29

What % of children get eczema?

Answer 29

20% of children get eczema

Question 30

What % of eczema cases are allergic?

Answer 30

Only 10%! These cases tend to be more severe (kids with perioral eczema from foods; adults with facial/hand eczema from dustmites)

Question 31

What layer of skin does eczema affect?

Answer 31

Epidermis

Question 32

2 SEs of topical steroid used near the eye

Answer 32

Glaucoma, cataracts

Question 33

Does a steroid for psoriasis need to be potent or not? Why?

Answer 33

POTENT! Scale is thick, so needs a strong steroid to get through it.

Question 34

What 2 common myths are thought to cause acne?

Answer 34

Diet and insufficient facial washing

Question 35

25yo unusually bulky man complains of acne. Possible cause?

Answer 35

Anabolic steroids

Question 36

29yo lady can't fall pregnant. Quite overweight, hairy face, acne. Possible cause of acne?

Answer 36

PCOS

Question 37

2 things to do for ALL patients with acne (a question and something to check)

Answer 37

Ask psychological impact. Check for scarring (needs more aggressive treatment)

Question 38

"I have rosacea. What should I avoid?"

Answer 38

Things that exacerbate flushing, like sunlight, alcohol, spicy food, heat

Question 39

Lady has been using topical steroid on her face for a while. Now complains of papules around her mouth. Diagnosis? Cause? Treatment?

Answer 39

Perioral rosacea. Stop the topical steroid (expect rebound worsening). Give Abx as for acne for 1-2 months. Should clear completely and not recur.

Question 40

Type of laser for persistent erythema and flushing in rosacea patient?

Answer 40

Vascular laser

Question 41

Type of laser for man with established rhinophima?

Answer 41

Ablative laser

Question 42

Boy in Year 3 gets golden crusted pustules around his lips. His mum refuses to keep him away from school: soon all the kids at his table have the same crusts - in armpits and hands too

Answer 42

Impetigo (school sores)

Question 43

Started as a small inflammation around an armpit hair, now large pustule that is tender and firm to touch, with lots of redness around it

Answer 43

Furuncle

Question 44

Woman who owns cats complains of scaly "crop circles" on her arms and legs. Itchy, central clearing.

Answer 44

Tinea corpis (Trichophyton rubrum, or Microsporum canis from cats and dogs)

Question 45

Rugby play with very itchy genitalia. Red scaly patch spreading from the scrotum down the inner thigh.

Answer 45

Tinea curis (jock itch)

Question 46

Man had to grow a beard after he got "pimples" around each hair stubble. Improved with chlorhexidine wash...until he got the same thing on his buttocks.

Answer 46

Folliculitis

Question 47

Lazy teenage boy can't be bothered wearing new socks each day. He notes that the skin between his toes is moist and peeling away.

Answer 47

Tinea pedis (Athlete's foot). Give Lamisil - terbinafine antifungal cream

Question 48

After getting a kidney transplant (now on ciclosporin) Sam embarrassed by the bumps on her fingers (they disrupt the nail growth too) and soles of her feet.

Answer 48

Warts (Human Papilloma Virus). Cryotherapy or salicylic acid paints ("Wart Off")

Question 49

56yo woman complains of pain "on her left rib". Two days later a vesicular red rash appears. She sees you two days later Treatment?

Answer 49

Give oral aciclovir (within 72 of vesicles appearing)

Question 50

How long is shingles contagious for?

Answer 50

Until the vesicles have crusted over, and now new vesicles are forming.

Question 51

"My shingles pain is so bad, what can I put on it?"

Answer 51

Capsaicin cream

Question 52

This is the most dangerous dermatome for shingles to affect

Answer 52

Ophthalmic division of trigeminal nerve (V1). Can affect cornea, leading to blindness. IV aciclovir, and aciclovir eye drops!

Question 53

24yo woman is embarrassed by the cluster of small vesicles on her lower lip. They keep appearing whenever she gets stressed. Treatment?

Answer 53

Coldsores. Topical aciclovir (Zovirax)

Question 54

Man with tinea pedis develops a red, oedematous rash in his left foot. It seems to be spreading upwards. It is very warm to touch. Little red spidery lines spreading up from it (name?)

Answer 54

Cellulitis. Lines are lymphangitis; infection spreading in the lymphatics

Question 55

What drug for cellulitis? What if they're allergic to penicilin?

Answer 55

Flucloxicillin. Or clindamycin if allergic to penicillins.

Question 56

Man develops flaky, well-demarcated discoloured patches on his trunk - they're like dark spots against his white skin. The flakes look like bran. Cause?

Answer 56

Pityriasis versicolour. Caused by yeasts of Malassezia genus.

Question 57

Woman with a diffuse, erythematous, scaly discoid rash. Started as one patch, but then spread all over her body. Lesions follow the skin creases - her back looks like a Christmas tree. Cause?

Answer 57

Pityriasis rosea. Caused by herpes virus. No treatment, goes in 6-12wks

Question 58

Redheaded kid is covered in brown spots on her face. They darken in summer, and lighten in winter. They fade away as she ages.

Answer 58

Ephelides (freckles)

Question 59

What causes the colour of freckles?

Answer 59

Increased melanin production in response to sun exposure

Question 60

After falling pregnant, Deb develops a blotchy brown symmetrical pigmentation over her face. Improves with hydroquinone + tretinoid + corticosteroid prescription cream.

Answer 60

Melasma

Question 61

Commonest type of lentigo. Not related to sun exposure. Develop in early childhood usually.

Answer 61

Lentigo simplex

Question 62

Lentigo that develops after sun exposure, especially on the back of old people's hands

Answer 62

Solar lentigo (actinic lentigo, liver spot)

Question 63

What causes the colour of lentigines?

Answer 63

Benign linear proliferation of melanocytes along the basal layer of the epidermis.

Question 64

This type of naevus is found in the basal epidermis and the upper dermis.

Answer 64

Junctional naevus. Flat, colourful macules.

Question 65

This type of naevus is found just in the dermis. Thick, protruding mole that may be skin coloured or brown.

Answer 65

Dermal naevus

Question 66

This type of naevus has naevus cells both at the junction of the epidermis and dermis, as well as within the dermis. Raised centre with a flat coloured border.

Answer 66

Compound naevus.

Question 67

What causes the colour of a naevus?

Answer 67

Nests of melanocytes that have proliferated. These melanocytes lack dendrites, so are called "naevus cells"

Question 68

Under what 3 circumstances is it OK to remove a mole?

Answer 68

Possible malignancy, nuicance (catches on clothes), cosmetic reasons

Question 69

What types of congenital naevi (birthmarks) are there?

Answer 69

Small, medium, giant, hairy congenital naevi. Cafe au lait macules. Speckled lentiginous naevi. Bluish marks = Naevus of Ota, mongolian spot.

Question 70

What types of acquired naevi are there?

Answer 70

Common (flat, uniform colour). Dysplastic (some ABCDE features). Spitz (pink or brown dome in kids). Halo (in puberty when white halo forms around mole, then mole disappears). Blue naevus. Cellular naevus (non-pigmented dermal mole). Meyerson naevus (mole surrounded by eczema)

Question 71

40yo man with Hx of intermittent burns each summer with an enlarging brown spot on his back.

Answer 71

Superficial spreading melanoma

Question 72

Black man with line under his toenail.

Answer 72

Acral lentiginous melanoma

Question 73

65yo woman with a "black ball" growing on her arm over the last 2 months.

Answer 73

Nodular melanoma

Question 74

Flat brown patch growing on 67yo man's nose over the past 10 years. He worked as a gardener his whole life.

Answer 74

Lentigo maligna melanoma

Question 75

Why is a melanoma that's confined to the epidermis cured if it's cut out?

Answer 75

Epidermis lacks lymphatics or blood, so melanoma cells can't spread

Question 76

What are some features on dermoscopy that are seen in melanomas?

Answer 76

Blue grey veil, multiple colours, multiple brown spots, pseudopods and radial streaming

Question 77

What % of melanomas arise from existing moles?

Answer 77

25%

Question 78

What % of melanomas arise out of the blue, from normal skin?

Answer 78

75%

Question 79

What are some risk factors for melanoma?

Answer 79

Having fair skin, many moles, many (>5) dysplastic moles, FHx melanoma, personal Hx melanoma or other skin cancer, increasing age

Question 80

What are the ABCDEs of melanoma?

Answer 80

Asymmetry, Border irregualrity, Colour variation, Diameter >6mm, Evolution over time

Question 81

2 fungal causes of pigmented lesions?

Answer 81

Pityriasis versicolour, Tinea nigra

Question 82

2 types of keratosis that can cause pigmented lesions?

Answer 82

Pigmented actinic (solar) keratosis, seborrhoeic keratosis ("stuck-on")

Question 83

Type of pigmented skin lesion caused by dermal histiocyte proliferation; buckles when pinched

Answer 83

Dermatofibroma

Question 84

Type of pigmented lesion that may appear after a splinter gets under the skin

Answer 84

Foreign body granuloma

Question 85

Type of pigmented lesion that is usually large, hairy, and over the back - caused by epidermal overgrowth?

Answer 85

Becker naevus

Question 86

Type of pigmented lesion seen on the soles of the feet of a runner

Answer 86

Talon noid (heel petechiae from trauma)

Question 87

3 types of vascular causes of pigmented lesions?

Answer 87

Port wine stain, stork bite, cherry haemangioma

Question 88

Type of pigmented lesion that looks like a strawberry or raw minced meat, appears after minor trauma like a pin prick or thorn scratch

Answer 88

Pyogenic granuloma

Question 89

Difference between a mole and a lentigo?

Answer 89

Bother are proliferation of melanocytes. In moles, proliferation is in nests (junctional, dermal, or compound). In lentigines, proliferation is in lines (along the basal layer of the epidermis.)

Question 90

2 melanocytic pigmented skin lesions caused by an increased amount of melanin

Answer 90

Ephelides and melasma

Question 91

3 non-melanocytic pigmented skin lesions caused by an increase in the number of melanocytes

Answer 91

Naevi, lentigines, melanoma