Photosensitivity

Question 1

What is porphyria?

Answer 1

A group of rare diseases in which porphyrins accumulate giving rise to neurological and dermatological symptoms. The accumulation is causes by the lack of an enzyme in the haem pathway so the porphyrin is not converted to the next.

Question 2

What are the typical presentations of porphyris cutanea tardia?

Answer 2

phototoxic skin- prickly pain
blisters that scar, fragility, hyperpigmentation, hypertrichosis (extra hair- esp. on cheeks), solar urticaria and morphoea

Question 3

What can cause Porphyria cutanea tardia?

Answer 3

things that upset the liver-

alcohol; viral hepatitis; oestrogens; haemochromatosis

Question 4

How does erythropoetic protoporphyria present?

Answer 4

In childhood with photosensitive skin- on exposure: pruritis; swelling; pain and erythema. longer term: patients may present with lichenification, hypopigmentation, hyperpigmentation and scarring of the skin

Question 5

What GI problem are Erythropoeitic protoporhyria patients at risk of?

Answer 5

gallstones

Question 6

What two systems are affected in acute intermittent porphyria (the madness of King George)?

Answer 6

CNS and GU

Question 7

What enzyme is deficient in erythropoeitic protoporphyria

Answer 7

ferrochelatase

Question 8

What protoporphyrian builds up in erythropoeitic protoporphyria?

Answer 8

protoporphyrian IX

Question 9

What enzyme has impaired function in acute intermittent porphyria?

Answer 9

Porphobilinogen deaminase