Photodermatology

Question 1

The skin phenotypes are defined by what grading system?

Answer 1

Fitzpatrick sun-reactive phototypes (1 is lighested, 6 is darkest)

Question 2

Porphyrias are a group of metabolic conditions caused by mutation in how many genes?

Answer 2

7

Question 3

The underlying pathology of porphyria is central to what substance?

Answer 3

Production of haem from iron

Question 4

Acute Intermittent Porphyria is caused by a lack of what enzyme?

Answer 4

PBG deaminase

Question 5

Erythropoetic protoporhyria is caused by a lack of what enzyme?

Answer 5

Ferrochelotase

Question 6

Porphyria cutanea tarda is caused by a mutation in which enzyme?

Answer 6

Uropophyrinogen decarboxylase (URO)

Question 7

What are the commoner skin porphyria features? (3)

Answer 7

• Blistering
• Fragility
• Acute phototoxicity

Question 8

What’s the most common porphyria in Scotland?

Answer 8

Porphyria cutanea tarda

Question 9

Second most common porphyria in Scotland?

Answer 9

Erythropoetic protoporphyria

Question 10

Porphyria cutanea tarda can result from what?

Answer 10

Chronic liver disease

Question 11

PCT commonly presents how?

Answer 11

Blistering of hands, fragile skin and mylea (firm spots which are little cysts at DEJ)

Question 12

Buzzwords for PCT include

Answer 12

Hyperpigmentation, hypertrichosis, solar utricaria, scalp erosions

Question 13

PCT is diagnosed how

Answer 13

By testing patient’s urine under a Woods lamp (positive fluorescence)

Question 14

How is PCT primarily managed?

Answer 14

By managing the underlying causative disease

Question 15

EPP patients will often have what emotional reaction to light?

Answer 15

Be afraid of it

Question 16

Common signs of EPP?

Answer 16

Acute reaction to light (itch, pain, rash)

Question 17

How is EPP diagnosed?

Answer 17

Quantifying porphyrins, flurocytes, transaminase levels

Question 18

How is EPP managed?

Answer 18

Counselling & 6 monthly FBCs (anaemia) and LFTs (liver failure common sequelae)

Question 19

What is the underlying pathophysiology of acute intermittent porphyria?

Answer 19

Acute build-up of ALA and PGB which are neurotoxic

Question 20

What’s the commonest trigger of attack in acute intermittent porphyria

Answer 20

Barbiturate

Question 21

How is acute intermittent porphyria managed?

Answer 21

Antioxidants, iron avoidance, prophylatic TL-01 phototherapy.