Other skin disease

Question 1

How does erythropoietic porphyria present?

Answer 1

Presents in early childhood - ‘child crying in the sun’

Discomfort, itch and tingling in skin when exposed to sunlight

Question 2

What is the cause of erythropoietinc porphyria?

Answer 2

A build up of protoporphyrin IX due to a lack of the enzyme ferrochelatase

Question 3

How does porphyria cutanea tarda present?

Answer 3

Presents in middle age with blistering, scarring and milia formation of dorsum of hands/forearms and often hypertrichosis
Can be associated with liver disease

Question 4

What is the cause of porphyria cutanea tarda?

Answer 4

Deficiency of uroporphyrinogen decarboxylase

Question 5

What is acute intermittent porphyria?

Answer 5

Impaired function of porphobilinogen deaminase resulting in an acute neurotoxic reaction

Question 6

Which strains of human papilloma virus are responsible for warts/verrucas?

Answer 6

Types 1-4

Question 7

Which skin rash is associated with coeliac’s disease?

Answer 7

Dermatitis herpeteformis

Question 8

What term best describes itch caused by damage to the central or peripheral nervous system?

Answer 8

Neuropathic

Question 9

What is the definition of neurogenic itch?

Answer 9

There is no actual damage to the CNS or nerves but there is an effect on neurotransmission e.g. jaundice, opiates

Question 10

What systems are important in maintaining good circulation in the lower limb?

Answer 10

Muscle pump
Venous valves
Pulse pressure

Question 11

How does rosacea present?

Answer 11

Erythema
Telangectasia
Papules
Pustules
Lymphoedema

Question 12

What is the pathology in rosacea?

Answer 12

Sebaceous gland hyperplasia however sebum production is normal

Question 13

Which systemic diseases are associated with itch?

Answer 13

Haematological
Paraneoplastic
Liver and bile duct
Psychogenic
Kidney disease
Thyroid disease

Question 14

Which type of hypersensitivity are bullous pemhigoid & pemphigus diseases?

Answer 14

Type 2

Question 15

What form are the rashes most associated with drug eruptions?

Answer 15

Exanthematous/morbilliform (looks like measles)/maculopapular

Question 16

What are the characteristics of an exanthematous drug eruption?

Answer 16

Idiosyncratic, T-cell mediated delayed type hypersensitivity (Type IV) reaction.
Usually mild & self limiting.
Widespread symmetrically distributed rash.
Mucous membranes usually spared.
Pruritus (itch) is common.
Mild fever is common

Question 17

When does an exanthematous drug eruption rash usually appear?

Answer 17

4-21 days after first taking drug

Question 18

What factors indicate a potentially serious exanthematous drug rash?

Answer 18

Involvement of mucous membrane and face
Facial oedema & erythema
Widespread confluent erythema
Fever (>38.5⁰C)
Blisters, purpura, necrosis
Lymphoadenopathy, arthalgia
Shortness of breath, wheezing

Question 19

What are the two possible mechanisms of an urticarial drug reaction?

Answer 19

Usually an immediate IgE- mediated hypersensitivity reaction (Type I) after rechallenge with drug
Direct release of inflammatory mediators from Mast cells on first exposure