what are some types of porphyria
- porphyria cutanea tarda
- erythropoietic protoporphyria
- acute intermittent porphyria
what is the most common type of porphyria
-porphyria cutanea tarda
what is porphyria
a group of diseases in which substances called porphyrins build up, negatively affecting skin or NS
cause of porphyria cutanea tarda
low levels of uroporphyrinogen III decarboxylase
-genetic and non-genetic (alcohol abuse, excess iron)
cause of erythropoietic protoporphyria
deficiency in ferrochelatase, leading to abnormal levels of protoporphyrin in RBC, plasma, skin and liver
cause of acute intermittent porphyria
deficiency in porphobilinogen deaminase
-attack caused by medication, alcohol, infections and change in sex hormone
presentation of PCT
- blistering in sun exposed areas
- mila (wee white spots)
- hyperpigmentation
- hypertrichosis (excess hair)
- solar urticaria (hives etc)
- morphoea (thickening of dermis)
presentation of erythropoietic protoporphyria
a few minutes of exposure induced erythema, swelling and pain
-after repeated exposure may present with lichnification, hypopigmentation, hyperpigmentation and scarring
presentation of acute intermittent porphyria
severe and poorly localised abdominal pain
- urinary symptoms
- psychiatric symptoms
- signs that suggest increased sympathetic activity
- proximal muscle weakness beginning in arms
diagnosis of PCT
woods lamp
- lab testing reveals high levels of uroporphyrinogen in urine
- if urine turns red on testing then condition is present
diagnosis of erythropoietic protoporphyria
- quantitive RBC porphyrins
- detection of plasmatic fluorescence peak at 634nm
- increased levels of protoporphyrin in faeces or electrolytes
diagnosis of acute intermittent porphyria
urine and serum show raised porphobilinogen
treatment for PCT
- treat underlying cause
- avoid alcohol, iron and excess sunlight
- low dose of antimalarials can be used, work by removing excess porphyrins from liver
treatment for erythropoietic protoporphyria
- avoid middle of day sunlight
- shade trees, windows ets
- topical sunscreen (ones containing zinc)
- prophylactic TL-01 phototherapy using UVB lamp
- antioxidants
- avoid iron
treatment for acute intermittent porphyria
- high carbohydrate if drug caused
- hematin and heme arginate is treatment in acute attack
