What is Porphyria Cutanea Tarda?
Porphyria Cutanea Tarda is one of the most common forms of porphyria in which there is blistering of the skin and the skin becomes very fragile when it is exposed to sunlight. These blisters tend to become chronic on the areas of the body that are exposed to sunlight in cases of Porphyria Cutanea Tarda. Due to Porphyria Cutanea Tarda, there can be excessive accumulation of iron in the liver which may result in some damage to the liver as well. The best way to diagnose Porphyria Cutanea Tarda is by doing a urine test which will show elevated levels of porphyrins in the liver. Additionally blood tests may also be done to check for the levels of porphyrins in the blood to confirmatively diagnose Porphyria Cutanea Tarda.
The treatment for Porphyria Cutanea Tarda involves a procedure called phlebotomy or by taking medication called hydroxychloroquine. Phlebotomy is a procedure in which blood is removed from the body so that the iron levels in the body becomes less which in turn helps in treatment of Porphyria Cutanea Tarda. This procedure is done in sessions which are set at an interval of 2 to 4 weeks apart. Hydroxychloroquine works by eliminating the excess porphyrins from the body by way of urine. When it comes to incidences, Porphyria Cutanea Tarda is a condition that tends to occur throughout the globe and is not localized to any one particular area.
In majority of the cases, Porphyria Cutanea Tarda is not inherited and is termed as sporadic Porphyria Cutanea Tarda but in rare cases this condition runs in families and is called as familial Porphyria Cutanea Tarda. In individuals who do not have deficiency of enzymes which is involved in blood production, they tend to suffer only from the sporadic form of Porphyria Cutanea Tarda.
What Causes Porphyria Cutanea Tarda?
Porphyria Cutanea Tarda is basically caused due to deficiency of an enzyme called uroporphyrinogen decarboxylase due to which there is accumulation of excess porphyrins in the liver. This may cause damage to the liver and about 40% of the individuals end up having cirrhosis of the liver and about 10% end up having liver cancer.
When these excess porphyrins are transported by the blood to the surface of the skin then there is development of the blisters on the skin surface that are exposed to sunlight. There are many factors which may lead to Porphyria Cutanea Tarda. These factors are:
- Presence of excessive iron in the liver
- Alcohol abuse
- Taking estrogen hormones
- Individuals with Hepatitis C can also have Porphyria Cutanea Tarda.
What are the Symptoms of Porphyria Cutanea Tarda?
The classic symptom of Porphyria Cutanea Tarda, which is the skin blisters, may not be immediately evident after exposure to sunlight and hence an individual may not suspect sunlight to be the cause of the symptoms. The classic presenting feature of Porphyria Cutanea Tarda is the recurring skin blisters which may be of variable sizes in the sun exposed areas of the skin like the face, arms, and behind the hands.
These blisters are then followed by development of scars and the blisters begin to form crusts and these take a very long time to heal. The skin of these parts becomes extremely fragile and become seriously injured even with a minor trauma like a cut or a bruise. Blisters may also be accompanied with swelling, itching, and erythema of the skin. There may also be increased hair growth along the face and other areas of the body exposed to the sun.
How is Porphyria Cutanea Tarda Diagnosed?
As stated, urine test is the best way to diagnose Porphyria Cutanea Tarda as this test will show elevated levels of porphyrins. Additionally, bloods tests may also be performed to confirm the diagnosis. In order to distinguish between Porphyria Cutanea Tarda and other forms of porphyria the pattern of the increased porphyrins are studied and with Porphyria Cutanea Tarda there is a specific pattern with which the physician can definitively diagnose this condition.
Additionally, physicians also do investigations to identify the cause for Porphyria Cutanea Tarda such as if there is increased accumulation of porphyrins in the liver or whether the individual is suffering from conditions like hepatitis C or HIV which is a common precipitating factor for Porphyria Cutanea Tarda.
How is Porphyria Cutanea Tarda Treated?
The most preferred way to treat Porphyria Cutanea Tarda is by removal of blood which is done by a procedure called phlebotomy. In this procedure more than half of the blood in the body is removed. This procedure is done in sessions which may be span up to 4 to 6 in two to four week intervals. What this procedure does is remove the excess iron that is inside the body and the functioning of the enzyme uroporphyrinogen decarboxylase returns back to normal and there is a gradual decline of the porphyrins that have accumulated. Once the porphyrins levels drop the skin symptoms also gradually resolve. The risk of this procedure is that the patient may become anemic due to loss of blood if the sessions are done too frequently.
Apart from this procedure, there are also certain medications that can be utilized for treatment of Porphyria Cutanea Tarda. Low doses of hydroxychloroquine have shown quite good efficacy in treatment of this condition. The function of this medication is to remove excess porphyrins in the liver and eliminate them through the body by way of urine, although if given in high doses it may result in removal of the porphyrins too quickly leading to potential liver damage. For people taking hormones like estrogen it is recommended to stop taking estrogen therapy so as to be treated for Porphyria Cutanea Tarda at least until the porphyrin levels are normalized.
Apart from these two modes of treatments mentioned above, complete abstinence from alcohol, avoiding sun exposure, and avoiding other precipitating factors are also recommended for treatment of Porphyria Cutanea Tarda.