Porphyrias
are
metabolic
disorders
of
heme
synthesis
.
Partial
enzymic
____________________
result
in
excessive
accumulation
and
excretion
of
5
-
aminolevulinic
acid
,
porphobilinogen
,
and
/
or
porphyrins
.
____________________
cutanea
tarda
(
PCT
)
is
the
most
common
of
the
porphyrias
____________________
North
America
and
Europe
.
First
described
by
Waldenström
in
1937
,
this
____________________
disorder
is
caused
by
a
deficiency
of
uroporphyrinogen
decarboxylase
,
an
____________________
in
heme
biosynthesis
.
Porphyrins
accumulate
in
the
liver
,
are
____________________
in
plasma
,
and
are
excessively
excreted
in
the
____________________
.
Exposure
of
patients
with
porphyria
cutanea
tarda
to
sunlight
results
in
____________________
skin
fragility
,
vesicles
,
bullae
,
hypertrichosis
,
hyperpigmentation
,
sclerodermoid
____________________
,
dystrophic
calcification
,
milia
,
and
scarring
in
a
photodistribution
.
Porphyria
cutanea
tarda
____________________
be
inherited
or
acquired
.
Treatment
options
include
phlebotomy
and
____________________
medications
.
Pseudoporphyria
describes
a
bullous
photosensitivity
that
clinically
and
histologically
____________________
porphyria
cutanea
tarda
.
However
,
no
demonstrable
porphyrin
abnormalities
____________________
present
.
In
1964
,
Zelickson
was
first
to
describe
this
type
of
phototoxic
____________________
in
patients
after
the
use
of
nalidixic
acid
.
The
skin
lesions
were
____________________
from
those
observed
in
patients
with
porphyria
cutanea
tarda
.
Since
this
initial
report
,
many
other
drugs
have
been
incriminated
in
mediating
this
type
of
bullous
photosensitivity
.
Pseudoporphyria
has
been
____________________
in
patients
with
chronic
renal
failure
treated
with
and
without
hemodialysis
and
in
those
with
excessive
exposure
to
ultraviolet
A
(
UV
-
A
)
by
tanning
beds
.
