Question 36#

Which of the following skin disorders is least associated with tuberculosis?

A. Scrofuloderma

Correct Answer E: Lupus pernio is sometimes seen in sarcoidosis but is not associated with tuberculosis.

Skin disorders associated with tuberculosis:

Possible skin disorders:

• Lupus vulgaris (accounts for 50% of cases)
• Erythema nodosum
• Scarring alopecia
• Scrofuloderma: breakdown of skin overlying a tuberculous focus
• Verrucosa cutis
• Gumma

Lupus vulgaris is the most common form of cutaneous TB seen in the Indian subcontinent. It generally occurs on the face and is common around the nose and mouth. The initial lesion is an erythematous flat plaque which gradually becomes elevated and may ulcerate later.

Question 37#

A 62-year-old male is referred to dermatology with a lesion over his shin. On examination shiny, painless areas of yellow skin over the shin are found with abundant telangiectasia.

What is the most likely diagnosis?

A. Pretibial myxoedema

Correct Answer B: 

Shin lesions: The differential diagnosis of shin lesions includes the following conditions:

• Erythema nodosum
• Pretibial myxoedema
• Pyoderma gangrenosum
• Necrobiosis lipoidica diabeticorum

Below are the characteristic features:

Erythema nodosum:

• Symmetrical, erythematous, tender, nodules which heal without scarring
• Most common causes are streptococcal infections, sarcoidosis, inflammatory bowel disease and drugs (penicillins, sulphonamides, oral contraceptive pill)

Pretibial myxoedema:

• Symmetrical, erythematous lesions seen in Graves' disease
• Shiny, orange peel skin

Pyoderma gangrenosum:

• Initially small red papule
• Later deep, red, necrotic ulcers with a violaceous border
• Idiopathic in 50%, may also be seen in inflammatory bowel disease, connective tissue disorders and myeloproliferative disorders

Necrobiosis lipoidica diabeticorum:

• Shiny, painless areas of yellow/red skin typically on the shin of diabetics
• Often associated with telangiectasia

Question 38#

Which one of the following conditions is least associated with pruritus?

A. Pemphigus vulgaris

Correct Answer A:  Pemphigus vulgaris is an autoimmune bullous disease of the skin. It is not commonly associated with pruritus.

Pruritus: The table below lists the main characteristics of the most important causes of pruritus:

Other causes:

• Hyper- and hypothyroidism
• Diabetes
• Pregnancy
• 'senile' pruritus
• Urticaria
• Skin disorders: eczema, scabies, psoriasis, pityriasis rosea 

Question 39#

A 24-year-old female with a history of anorexia nervosa presents with red crusted lesions around the corner of her mouth and below her lower lip.

What is she most likely to be deficient in? 

A. Zinc

Correct Answer A: Vitamin B2 (riboflavin) deficiency may also cause angular cheilosis.

Zinc deficiency:
Features:

• Perioral dermatitis: red, crusted lesions
• Acrodermatitis
• Alopecia
• Short stature
• Hypogonadism
• Hepatosplenomegaly
• Geophagia (ingesting clay/soil)
• Cognitive impairment

Question 40#

Which one of the following statements regarding acne vulgaris is incorrect?

A. Follicular epidermal hyperproliferation results in obstruction of the pilosebaceous follicle

Correct Answer E: Acne is actually more common in females after the age of 25 years.

Acne vulgaris:

Acne vulgaris is a common skin disorder which usually occurs in adolescence. It typically affects the face, neck and upper trunk and is characterized by the obstruction of the pilosebaceous follicle with keratin plugs which results in comedones, inflammation and pustules. 

Epidemiology:

• Affects around 80-90% of teenagers, 60% of whom seek medical advice
• Acne may also persist beyond adolescence, with 10-15% of females and 5% of males over 25 years old being affected

Pathophysiology is multifactorial:

• Follicular epidermal hyperproliferation resulting in the formation of a keratin plug. This in turn causes obstruction of the pilosebaceous follicle. Activity of sebaceous glands may be controlled by androgen, although levels are often normal in patients with acne
• Colonization by the anaerobic bacterium Propionibacterium acnes
• Inflammation