It is the most prevalent type of Porphyria. Porphyria Cutanea Tarda has several other names such as symptomatic porphyria, idiosyncratic porphyria, acquired hepatic porphyria, and chemical porphyria. 80% of cases of this disease are acquired; however, 20% of cases are a result of “it runs in the family”. In this disease, the heme synthetic enzyme uroporphyrinogen decarboxylase (UROD) becomes deficient. The PCT of the familial type usually develops due to the autosomal dominant inheritance of a single mutation of the UROD (uroporphyrinogen decarboxylase) gene.
This disorder is found in both males and females. It is found all races around the world. PCT appears after the age of 30 and it is extremely rare in children. Moreover, it is found as approximately 1 in 20,000 individuals of a population.
2) What are Porphyrias?
A porphyria is a group of disorders that occurs due to the deficiency of certain enzymes to make heme. Heme is a protein of blood that transports oxygen all over the body. To make heme the body uses different enzymes to transform certain compounds into porphyrin then into heme. If this pathway breaks down, porphyrin starts accumulating in the body despite converting into heme, which ultimately leads to acute pain or skin damage. The type of porphyria depends upon which enzyme is lacking.
3) Causes and trigger:
PCT is caused by the deficiency of an enzyme called uroporphyrinogen decarboxylase (UROD) which helps to convert porphyrins into heme. Iron overload disorder is a risk factor associated with the development of PCT. The liver usually removes the toxic porphyrin from the body and secrete it into bile. So a large amount of toxic porphyrin in the body can ultimately lead to liver damage. Some parts of the liver may get inflamed or scarring occurs around the portal vein. People with if not treated properly, PCT leads to cirrhosis (scarring of the liver) and liver cancer. Moreover, chronic liver conditions such as hepatitis C, HIV, and excessive alcohol consumption can cause PCT. Estrogen containing drugs such as used for prostate cancer treatment (alpha-blockers) and oral contraceptive pills can cause the development of porphyrins in the blood, skin, and liver.
However, smoking and drinking alcohol trigger the condition of PCT.
In some people, UROD deficiency is genetic. However, most people with this inherited deficiency disease never show or experience any symptoms.
4) Signs and Symptoms:
The symptoms vary from person to person. This disorder is accompanied by skin abnormalities. The patients of PCT become photosensitive. They experience extreme sensitivity to sunlight due to the accumulation of porphyrin compounds under the surface of the skin that has been oxidized by free radicals or sunlight. Moreover, exposure to the sun can cause painful blistering, increased skin fragility that can peel even on minor trauma, hypertrichosis which is abnormal hair growth related to their age, sex, race and milia that are bump-like a cyst with whiteheads under the skin, occurring on the light-exposed areas such as the back of the hands while facial features include hyperpigmentation in which skin darkens due to scarring, hypertrichosis and morphorea like changes. With the passage of time, hyperpigmentation or hypopigmentation occurs in different parts of the skin in which the skin darkens or fades.
The symptoms occur when the levels of UROD drop to almost 20% of normal levels.
Identification of symptoms, patient history, complete clinical evaluation and variety of specialized tests help in diagnosing Porphyria cutanea tarda. There are certain screening tests to diagnose PCT. These screening tests also help in differentiating Porphyria cutanea tarda from variegate porphyria and erythropoietic porphyria.
Familial porphyria cutanae tarda can be traced by checking the presence of a reduced amount of UROD enzyme in erythrocytes (red blood cell). Another diagnostic test is molecular genetic testing. Family history also confirms the chances of PCT.
PCT can easily be diagnosed by urine test which will indicate increasing levels of porphyrin in the urine. It can also be diagnosed by a blood test to find elevated levels of porphyrin in blood plasma. Furthermore, stool test is another way for the verification of PCT by detecting increased levels of porphyrins.
6) Questions that Patients Should Ask the Doctor:
- How did I get porphyria?
- Which type of porphyria do I have?
- Which tests will you recommend me ?
- How can I avoid and take care of my triggers?
- How can I avoid sun exposure?
PCT is the most easily treatable form of porphyria. First of all, we need to take care of aggravating factors such as estrogen-containing drugs. After that, the standard treatment includes the regularly scheduled phlebotomies to reduce porphyrin levels and iron in the liver. Phlebotomy is a safe and simple procedure in which the blood is removed through veins. Continuous phlebotomies help in the reduction of iron levels in the body because most of the iron is found in red blood cells. Phlebotomies go on until the target level (less than 20 nanograms) of ferritin is achieved. Ferritin is an iron compound that is used as the basic indicator of the presence of iron in the human body.
If there is any contraindication to phlebotomy like the person is anemic so another treatment option includes the low dosage of anti-malarial drugs such as chloroquine and hydroxyl chloroquine which help in the reduction of iron levels in the liver.
8) Quick Facts about Porphyria Cutanea Tarda:
- PCT is a rare disease.
- This affects all the races and gender equally.
- Its incidence is 1 in 20,000 individuals.
- Porphyria cutanae tarda is most common type of porphyria among all.
- It is a blood disorder that mostly affects the skin and liver.
- PCT usually affects adults older than 30 and rare in children.
Although, Porphyria cutanea tarda is a rare disease in which the liver and skin are affected due to disorders in blood but luckily it can be cured. The proper treatment can cope with this disease. If left unhandled, it can be dangerous. This most common type of porphyria makes the patient sensitive along with severe damage to the liver. Lastly, PCT is curable and treatment is quite beneficial if the patient undergoes in it regularly. Read more