Porphyria Educational Services
PORPHYRIA EDUCATIONAL SERVICES BULLETIN
Vol. 2 No. 10 March 5, 2000
FOCUS: Porphyria Cutanea Tarda.
Porphyria cutanea tarda (PCT) is the most frequent form of
any of the porphyrias. It is basically a cutanous form of porphyria.
PCT can be inherited as well as acquired.
The underlying enzymatic defect in PCT is a reduced activity of the enzyme
uroporphyrinogen decarboxylase (Uro-D).
Researchers have been able to determine that there are four different
types of Uro-D disturbances which are are known.
Pseudoporphyrias such as porphyria cutanea uraemica or drug-induced
PCT-like skin symptoms can be distinguished from PCT.
Porphyrinogens such as estrogens or alcohol, or other inducers of P450
isoenzymes can be triggers for PCT.
Polymorphisms of P450 isoenzymes, iron overload and
infection with hepatitis C virus play an important role in the
etiopathogenesis of PCT disease manifestation.
Dominant clinical symptoms are bullae, increased cutaneous vulnerability,
hypertrichosis and elastosis. These distinctions are best clinically
diagnosed by specialists in dermatology.
Biochemically, total porphyrin levels in urine are increased with a
predominance of uroporphyrin and heptacarboxylic porphyrin.
Isocoproporphyrin is demonstrable in stool collections.
To date the best therapeutic strategies are the oral administration
of chloroquine 125 mg twice a week and repetitive bloodlettings
or the combination of both.
With repeated blood draws it is necessary to be on guard for
the formation of anemia.
Reducing direct exposure to sunlight is also recommended.
Also reducing direct contact with many chemical toxins will help
to guard against triggering the PCT.
Joann Jeffries NP Guest Columnist