BOF: 2.35
A 42-year-old female presents with a blistering rash on
her hands on exposure to sunlight. She is an intravenous drug abuser, drinks
24 units of alcohol per week and smokes 10 cigarettes per day.
On examination of her hands there are blisters, erosions
scars and milia. The skin is pigmented and fragile. She looks emaciated she
has clubbing palmar erythema and spider naevi. There is tense ascites and the
liver and spleen are not palpable.
Investigations reveal a macrocytic anaemia and disordered
liver function. She is hepatitis-C PCR positive and her ferritin levels are
within the normal range.
In this patient treatment of the skin condition should be
with:
a)
Desferrrioxamine
b)
Venesection
c)
Low dose chloroquine
d)
Penicillamine
e)
Dapsone
Answer:
c)
The clinical features suggest the patient has porphyria
cutanea tarda. This is essentially a liver disorder that presents with skin
manifestations. It is caused by an endogenous inhibitor of the hepatic
uroporphyrinogen decarboxylase enzyme. The inhibitor forms in the presence of
iron and an oxidative environment. The porphyrins that are formed become toxic
when exposed to sunlight. Where iron overload is not the cause of the problem
treatment with low dose chloroquine (125 mg twice weekly) is effective
treatment.
