Disease Profiles: Photodermatology

Question 1

Define photosensitivity

Answer 1

Describes a group of skin disorders that result from exposure to normal levels of UV light exposure

Question 2

Which porphyria most commonly presents in females around the age of 30?

Answer 2

Acute intermittent porphyria

Question 3

What are porphyrias?

Answer 3

Group of photosensitivity disorders resulting from an inherited or acquired defect in the enzymes required to produce adequate amounts of haem, with the subsequent accumulation of porphyrins

Question 4

Describe the management of erythropeotic protoprophyria

Answer 4

Visible light photoprotection measures, prophylactic TL-01 phototherapy

Antioxidants, avoid iron

Question 5

Name 4 common causative drugs known to cause drug-induced photosensitivity

Answer 5

NSAIDs, diuretics, amiodarone, antibiotics e.g. tetracyclines, ciprofloxacin

Question 6

Which Fitzpatrick skin type is very fair, always burns and never tans?

Answer 6

I

Question 7

Describe the clinical presentation of erythropeotic protoprophyria

Answer 7

Typical presentation is child screaming when they are placed out in the sun

No evident rash but there will be burning and itching on the skin with sun exposure

Question 8

Which investigations would you perform in suspected porphyria cutanea tarda?

Answer 8

Bloods - porphyrin studies

Woods lamp - urine shines pink instead of blue

Question 9

Name the enzyme deficient in porphyria cutanea tarda

Answer 9

Uroporphyrinogen decarboxylase

Question 10

Which porphyria is the most common, and is usually seen in middle aged men?

Answer 10

Porphyria cutanea tarda

Question 11

What is the normal human skin reaction to acute sunlight exposure?

Answer 11

Reddens/tans

Question 12

Which Fitzpatrick skin type is fair, usually burns and sometimes tans?

Answer 12

II

Question 13

Describe the management of porphyria cutanea tarda

Answer 13

Establish and treat the underlying cause e.g. alcohol, viral hepatitis

Question 14

Describe the clinical presentation of xeroderma pigmentosum

Answer 14

Severe photosensitivity, accelerated photo ageing, ocular damage, and early formation of skin cancers

Question 15

Describe the management of xeroderma pigmentosum

Answer 15

Patients are required to undertake strict sun avoidance

Question 16

Name the porphyrin which accumulates in porphyria cutanea tarda

Answer 16

Uroporphyrinogen

Question 17

Name the porphyria which is most commonly seen in children

Answer 17

Erythropeotic protoprophyria

Question 18

Name the enzyme deficient in erythropeotic protoprophyria

Answer 18

Ferrochelatase

Question 19

Which porphyria is associated with liver disease, so often seen in those with haemochromatosis, hepatitis or alcohol misuse?

Answer 19

Porphyria cutanea tarda

Question 20

Which Fitzpatrick skin type is brown, never burns and always tans?

Answer 20

V

Question 21

Describe the prognosis of xeroderma pigmentosum

Answer 21

Most will die in teenage or early adult years due to skin cancer

Question 22

What is the normal human skin reaction to chronic sunlight exposure?

Answer 22

Thickens

Question 23

Name the enzyme deficient in acute intermittent porphyria

Answer 23

Porphobilinogen deaminase

Question 24

Which Fitzpatrick skin type is black, never burns and always tans?

Answer 24

VI

Question 25

Name the porphyrin which accumulates in acute intermittent porphyria

Answer 25

Porphobilinogen

Question 26

Describe the clinical presentation of porphyria cutanea tarda

Answer 26

Blistering lesions on sun exposed sites that heal with scarring and are associated with hyper pigmentation

Hypertrichosis, solar urticaria, morphoea

Question 27

Which Fitzpatrick skin type is medium, sometimes burns and usually tans?

Answer 27

III

Question 28

How would you monitor a patient with erythropeotic protoprophyria?

Answer 28

6 monthy LFTs and RBC porphrins

Question 29

What is xeroderma pigmentosum?

Answer 29

Refers to a group of autosomal recessive genetic disorders caused by a deficieny in the DNA repairs mechanisms in the skin

Question 30

Which Fitzpatrick skin type is olive, rarely burns and always tans?

Answer 30

IV

Question 31

Name the porphyrin which accumulates in erythropeotic protoprophyria

Answer 31

Protoporphyrin IX

Question 32

Describe the clinical presentation of acute intermittent porphyria

Answer 32

Acute abdomen, mood disturbance, neurological symptoms, seizures

Unlikely to actually present with cutaneous symptoms