Dermatology Cases

Question 1

How to describe a skin lesion

Answer 1

Distribution (flexor, extensor, acral, uni/bilateral)
Shape and size (annular, linear, nummular)
Colour (erythematous, purpura, erythroderma, hypo/perpigemented)
Morphology (flat macule/patch, elevated papule/nodule/plaque/cyst, fluid filled vesicle/billae/pustule)

Question 2

Layers of the epidermis

Answer 2

Stratum: corneum, lucidum, granulosum, spinosum, basale

Question 3

Function of Langerhans cells, melanocytes, Merkel Cells

Answer 3

Langerhans cell is an APC. Melanocyte makes melanin for UV protection. Merkel cell involved in sensory perception

Question 4

Categorize cutaneous malignancies

Answer 4

melanoma

non-menaloma skin cancer (BCC and SCC)

Question 5

Actinic keratosis most likely to develop into

Answer 5

SCC

macular/erthematous/crust/scale

Question 6

Types of Inflammatory dermatitis

Answer 6

Psoriasis
Atopic dermatitis
Eczema
Contact dermatitis (allergic and irritant)

Question 7

A 78 year-old Caucasian man presents to the GP for evaluation of a skin lesion. On examination, the GP finds a 0.7 cm translucent papule with central ulceration and rolled borders, surrounded by prominent telangiectasias. This lesion most likely represents:
A. Molluscum contagiosum
B. Basal cell carcinoma
C. Bowenoid papulosis
D. Squamous cell carcinoma
E. Melanoma

Answer 7

Basal cell carcinoma

translucent papule, central ulceration, rolled borders, telangiectasia

Question 8

A 75 year-old former groundkeeper attends GP practice for evaluation of some itchy lesions on his scalp. On inspection you see multiple macular erythematous lesions with overlying crust and scale. You treat the patient’s actinic keratoses. These lesions are most likely to develop into:
A. malignant melanoma
B. squamous cell carcinoma
C. Bowen’s disease
D. basal cell carcinoma
E. cutaneous T-cell lymphoma

Answer 8

SCC

Question 9

A 46 year-old travel journalist presents to the GP with a new lesion on her right thigh. The lesion has been present for 4 months. It started as a small pink patch which she says has grown in size. You observe a 1-cm macule with grey, brown, and pink colors, irregular borders, and a small area of ulceration. Most likely diagnosis?
A. SCC
B. BCC
C. AK
D. Malignant melanoma
E. Acrokeratosis paraneoplastica

Answer 9

Malignant melanoma
(new lesion, grown in size, colour variation, irregular borders, ulceration)

Question 10

A 55 year-old male smoker presents to clinic complaining of an itchy rash. On inspection you find multiple erythematous plaques with silvery scale on extensor surfaces of his upper limbs. Which condition?
A. Atopic dermatitis
B. Dermatitis herpetiformis
C. Herpes zoster
D. Plaque psoriasis
E. Pityriasis rosea

Answer 10

Plaque Psoriasis

smoker, pruritis, silvery scale, extensor surfaces

Question 11

A 4-year old child attends clinic with his mother. She reports that he has a widespread itchy rash that keeps him awake at night. On examination you see erythematous patches in the popliteal and antecubital fossae, and on the trunk. There are excoriation marks and weeping. Which condition is associated with this child’s rash?
A. Celiac disease
B. Crohn’s disease
C. Asthma
D. Atrial septal defect
E. Pyloric stenosis

Answer 11

Asthma

atopic dermatitis - erythematous, popliteal+ antecubital fossae, excoriation, weeping

Question 12

A 34 year-old Nigerian woman presents to clinic with cough and shortness of breath. You perform a general examination and incidentally find tender nodules and plaques on the anterior aspects of her lower legs. A CXR reveals hilar lymphadenopathy. 
A. Leukemia
B. Sarcoidosis
C. Sweet syndrome
D. Drug reaction
E. Infectious mononucleosis

Answer 12

Sarcoidosis

tender nodules, palques on ant legs, hilar lymphadenopathy

Question 13

A 34 year-old male with history of HSV infection presents to the dermatology clinic with abrupt onset of asymptomatic red lesions on his face and the extensor surfaces of his hands and elbows. On inspection the lesions are target-like in appearance. Which diagnosis do you need to consider?
A. Stevens Johnson syndrome
B. Dermatitis herpetiformis
C. Herpes zoster
D. Erythema multiforme
E. Granuloma annulare

Answer 13

Erythema multiforme

HSV infection, face and hands, target-like appearance

Question 14

A 7 year-old boy is escorted by his mother to the GP for evaluation of a rash. On examination he has multiple small papular lesions on his trunk with central umbilication. He is otherwise well. His mother reports 3 of his classmates have similar symptoms. 
A. Chickenpox
B. Molluscum contagiosum
C. Erythema infectiosum
D. Impetigo
E. Eczema

Answer 14

Molluscus contagiosum

papular lesions, umbilication