Porphyria's

Question 1

what is meant by cutaneous photosensitivity?

Answer 1

abnormal skin reaction to UV/visible light

Question 2

what is porphyria?

Answer 2

a disease where there is a build up of porphyrins caused by reduced enzyme activity in the haem pathway

react with light to produce skin reactions

Question 3

name the three most common porphyrias

Answer 3

porphyria cutanea tarda

erythropoietic protoporphyria

variegate porphyria

Question 4

how does porphyria cutanea tarda arise?

Answer 4

reduced activity of uroporphyrinogen decarboxylase causes build up of uroporphyrins that react with light

Question 5

list symptoms of porphyria cutanea tarda

Answer 5

blistering
skin fragility
hyperpigmentation

Question 6

list four causes of porphyria cutanea tarda

Answer 6

alcohol
viral hepatitis
high oestrogen
haemochromatosis

Question 7

how does erythropoietic protoporphyria arise?

Answer 7

reduced activity of ferrochelatase causes build up of protoporphyrins

Question 8

list symptoms of erythropoietic protoporphyria

Answer 8

swelling
burning
itching
pain

Question 9

how does acute intermittent porphyria arise?

Answer 9

reduced activity of PBG deaminase causes build up of uroporphyrins