What Is Porphyria Cutanea Tarda?

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Porphyria cutanea tarda (PCT) is the most common type of porphyria. Porphyrias are a rare group of diseases that develop from problems with the process of creating new blood cells in the body.

Porphyrias occur in as few as 1 in 50,000 people. There are at least eight types of porphyrias, and PCT is the most common one. PCT is estimated to occur in between 1 in 10,000 and 1 in 25,000 people.

Here is an overview of porphyria cutanea tarda, including its symptoms, how it is diagnosed, and the options for treatment.

A person laying on a bench in the shade shielding their eyes from the sunlight.

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Porphyrias are divided into two groups:

  • Acute intermittent porphyria, which affects the nervous system and, in some cases, the skin
  • Subcutaneous porphyria, which primarily affects the skin

PCT falls into the subcutaneous porphyria category and is the most common type in this group.

The symptoms of PCT can vary from one person to the next, but sensitivity to sunlight is common in most people with the condition. When exposed to sunlight or to other triggers, people with PCT may have symptoms like:

  • Blistering
  • Scarring
  • Darkening or discoloration of the skin
  • Changes in hair texture
  • Small white bumps called milia
  • Hardened or waxy skin

While PCT mostly affects the skin, it can also cause complications to other organ systems, including:

  • Increased iron in the liver (hepatic siderosis)
  • Fat accumulation in the liver (steatosis)
  • Liver inflammation (portal triaditis)
  • Thickening or hardening of the portal vein (periportal fibrosis)
  • Scarring of the liver (cirrhosis)
  • Liver cancer


Porphyrias are usually caused by genetic mutations, but gene mutations are less frequently the culprit behind PCT.

What Is Porphyria?

Porphyrias are a group of conditions that develop when a part of the process used to create blood cells is disrupted.

When this happens, porphyrins—a chemical within the body that is transformed into heme and later hemoglobin—build up in the blood and tissues.

Acute porphyrias that last for weeks and cause neurological symptoms can develop because of the buildup, as can subcutaneous porphyrias, which last a lifetime and come with periods of flare-ups and remissions.

Only about 20% of PCT cases are linked to genetic mutations. Specifically, PCT is caused by a mutation in the gene that creates an enzyme called uroporphyrinogen decarboxylase (UROD) that works in the liver.

In the remaining 80% of cases, there is a deficiency in the UROD enzyme occurs and other factors like:


Making a diagnosis of any type of porphyria starts with talking to your doctor about your symptoms, as well as discussing your family and personal medical histories. If other people in your family have porphyria, genetic testing might be the first step.

When there is no known family history, your doctor may ask you to provide a blood, stool, or urine sample for porphyrin testing. The test will measure the amount of porphyrin in your blood. An elevated level can signal porphyria.

After that testing is done, genetic testing can be used to determine which type of porphyria you have.


PCT is the most treatable type of porphyria. One of the primary treatments is a technique called therapeutic phlebotomy, which relies on scheduled blood draws to help decrease the levels of iron and porphyrin in the liver.

While it may sound extreme, the therapy involves a simple intravenous (IV) blood draw that is similar to those taken for routine lab tests. Usually, five to eight treatments are enough to put PCT into remission and get your symptoms under control.

Other treatments include medications like chloroquine and hydroxychloroquine, which are typically used to treat malaria but are also effective at lowering the iron levels in your liver.

Usually, the use of these medications is reserved for people who are not able to have therapeutic phlebotomy.

Besides treatment with phlebotomy or medications, one of the main ways that you can control PCT is avoiding triggers for flare-ups on the condition, such as:

  • Sunlight
  • Smoking
  • Alcohol
  • Stress
  • Certain foods
  • Hormone medications


No type of porphyria can be cured. If you have PCT, there is reason to hope because it is the most treatable type of porphyria, and new targeted therapies are being investigated.

While most cases of PCT are limited to the skin, the disease can also cause serious complications in the digestive system, liver, and lungs, and may lead to cancer.

If the current treatments for PCT are not enough to control the condition, you may wish to consider enrolling in a clinical trial that is investigating new treatments.


Acute porphyrias can cause severe neurological symptoms, and subcutaneous forms of the disease like PCT can cause serious pain and discomfort.

Even though porphyrias are rare, PCT is the most common form of porphyria, so you might be able to find other people who are undergoing similar challenges. Consider joining online support groups and organizations for resources or just to have a safe space to communicate with others and feel less alone in your experiences.

Porphyria support and informational organizations include:


Porphyria cutaneous tarda is the most common type of porphyria. The condition is the result of inherited or acquired enzyme deficiencies that cause toxic chemicals to build up in your blood.

With PCT, the buildup is associated with sensitivity to sunlight and skin disorders. In some cases, other organs are also involved.

There is no cure for PCT, but the symptoms can generally be managed with existing treatments and clinical trials for new therapies that are underway.

A Word From Verywell

Chronic diseases, especially rare ones like porphyria, can be difficult to cope with. However, PCT is the most treatable of the eight types of porphyria. When you're first diagnosed, you might be overwhelmed as you try to take in all the information about the condition—especially how it might change your life.

Know that there are several treatments and lifestyle changes that can help you live well with the condition. With support from your healthcare team and the communities of people with porphyria, you won't have to go through it alone.

Frequently Asked Questions

  • Does porphyria cutanea tarda cause skin blisters?

    Yes, PCT can cause blistering and other skin symptoms when people with the condition are exposed to sunlight or other triggers.

  • Is there a cure for PCT?

    Like other forms of porphyria, there is no cure for PCT. However, it is one of the most treatable forms of the condition.

  • Is bloodletting a treatment for PCT?

    In a way, yes. Therapeutic phlebotomy is used to decrease the levels of iron and other components in the blood that can build up if you have PCT.

5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. National Organization for Rare Disorders. Porphyria cutanea tarda. Updated 2016.

  2. National Institutes of Health. Porphyria. Updated August 18, 2020.

  3. Poh-Fitzpatrick MB. Porphyria cutanea tarda: Treatment options revisited. Clin. Gastro. Hepato. September 14, 2012. 10(12):1410-1411. doi:10.1016/j.cgh.2012.09.005.

  4. Singal AK. Low-Dose hydroxychloroquine is as effective as phlebotomy in treatment of patients With Porphyria Cutanea Tarda. Clin. Gastro. Entero. December 2012;10(12):1402-1409. doi:10.1016/j.cgh.2012.08.038.

  5. Christiansen AL, Brock A, Bygum A, et al. Increased mortality in patients with porphyria cutanea tarda-A nationwide cohort study. J Am Acad Dermatol. September 2020;83(3):817-823. doi:10.1016/j.jaad.2019.07.082.

By Rachael Zimlich, BSN, RN
Rachael is a freelance healthcare writer and critical care nurse based near Cleveland, Ohio.