Photodermatology and Porphyrias

Question 1

Define photobiology

Answer 1

the study of non-ionising radiation on living systems

Question 2

How is photodermatology used in the hospital?

Answer 2

Treatment eg PUVA/UVB

Diagnostic eg photodermatoses

Question 3

What are photodermatoses?

Answer 3

Group of skin conditions associated by an abnormal reaction to UV light

Question 4

What is a porphyria?

Answer 4

group of very rare metabolic disorders that occur when your body is unable to produce enough haem

Question 5

4 types of porphyria?

Answer 5

phototoxic
blistering
acute attack (some not involving skin)
congenital

Question 6

Most common porphyria in Scotland?

Answer 6

Porphyria cutanea tarda

Question 7

Disease mechanism behind porphyria cutanea tarda?

Answer 7

lack of enzyme (uroporphyrinogen decarboxylase) in the 5th step of haem production

Question 8

Clinical presentation of porphyria cutanea tarda?

Answer 8

blisters
fragility
hyperpigmentation
solar urticaria
hypertrichosis (excessive hair growth)

Question 9

Investigation for porphyria cutanea tarda (PCT)?

Answer 9

woods lamp

Question 10

Underlying causes of PCT?

Answer 10

alcohol
viral hepatitis
oestrogens
haemochromatosis

Question 11

Disease mechanism for erythropoetic protoporphyria (EPP)?

Answer 11

inherited lack of production of the final enzyme involved in the production of haem

Question 12

Clinical features of erthropoetic protoporphyria (EPP)?

Answer 12

uncomfortable burning sensation on tops of hands, feet, face and ears after sun exposure in young children

Question 13

Investigations for EPP?

Answer 13

check levels of protoporphyrin in blood, transaminases

Question 14

Management of EPP?

Answer 14

6 monthly LFTs and RBC porphyrins,
Phototherapy,
Anti-oxidants,
AVOID IRON