What Is Acute Intermittent Porphyria?

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Acute intermittent porphyria (AIP) is a rare disease that is caused by a problem with how blood cells are made. It’s one type of a larger group of rare conditions called porphyrias.

Porphyrias can affect the skin and nervous system. The conditions develop when a gene mutation interrupts the chemical process that is responsible for creating blood cells. When the process is disrupted, a chemical that is meant to be used to create hemoglobin builds up in your blood and tissues.

This article will cover how acute intermittent porphyria develops, how it is different from other forms of porphyria, and what to expect if you have the condition.

Acute Intermittent Porphyria Symptoms - Illustration by Jessica Olah

Verywell / Jessica Olah


The symptoms of AIP can vary, but the hallmark of this type of porphyria is neurological symptoms like:

The difference between AIP and other acute porphyrias is how often the symptoms appear and how long they last.

What Is Porphyria?

Porphyrias develop if there is a buildup of porphyrins and porphyrin precursors in the blood. These chemicals are usually used to make heme and later hemoglobin—the cell that carries oxygen through your blood.

If you have porphyria, you are deficient in an enzyme that converts porphyrin to heme, causing these chemicals to build up past normal levels.

Porphyrias are generally split into two categories based on how the chemical buildup affects your body:

  • Acute porphyrias affect the nervous system and skin and can last for several weeks.
  • Subcutaneous porphyrias only affect the skin, but create chronic problems.

AIP is a type of acute porphyria. Other types of porphyria that fall into the acute porphyria category include:

  • Delta-aminolevulinic acid (ALA) dehydratase deficiency porphyria
  • Variegate porphyria
  • Hereditary coproporphyria

AIP occurs as a limited episode or attack that can last from hours to days. However, without proper diagnosis and treatment, the episodes can last a week or months.

Once you recover from an attack, you are typically free from symptoms. However, recovery from one attack does not mean that the condition is resolved. Some people with AIP—3% to 5%—have recurring attacks (often at least four each year) for several years.


While some forms of porphyria are acquired, most are the result of a genetic mutation that is passed through families. Each form of porphyria is associated with a different gene mutation. For AIP, the affected gene is one that makes an enzyme called hydroxymethylbilane synthase (HMBS).

Not everyone with AIP has symptoms. In most cases, the symptoms of the condition do not develop unless they are triggered by things like:

  • Certain drugs or medications
  • Alcohol consumption
  • Fasting or dieting
  • Stress
  • Infections
  • Hormonal changes

When AIP is triggered, not only are porphyrin precursors not converted into heme as they should be, but your body also starts overproducing the chemicals. The overproduction increases how much porphyrin builds up in your body.


Getting a diagnosis of AIP can be difficult because of how quickly each attack subsides and how infrequently they can develop in the first place. Additionally, AIP symptoms can be caused by many other neurological conditions.

If you know you have a family history of porphyria, diagnosing the condition will probably be a quicker process. If no one else in your family has porphyria, your doctor will talk to you about your symptoms and do tests that can eliminate more common conditions that could explain your symptoms.

If your doctor decides to test you for porphyria, you will be asked to provide samples of blood, urine, or stool for testing. A lab will measure the porphyrin levels in your samples.

High concentrations of these chemicals can lead to a porphyria diagnosis. Genetic testing will come next to help your doctor figure out the specific type of porphyria that you have.


Acute attacks of AIP are usually treated with an infusion of heme, which is created by separating heme cells from donated blood. For the best results, these infusions should be given as soon as possible after the start of a severe or moderate attack.

Other treatments can include glucose and fluid infusions. It’s also important to address the other symptoms of AIP, like a racing heart (tachycardia) and muscle weakness, because they can lead to complications.


There is no cure for any form of porphyria, but treatments can relieve your symptoms and help prevent complications. While treatments for AIP are usually very effective, a delay in diagnosis or treatment can be fatal.

When fatal, the primary cause of death in people with AIP is:

  • Misdiagnosis that led to a delay in treatment or being treated with medications that made the condition worse
  • Prolonged mechanical ventilation because of respiratory muscle weakness
  • Cardiac arrest from abnormal heart rhythms

Improving the Odds

Better diagnosis and disease management has led to a decrease in mortality from AIP over the last few decades. According to a recent report, mortality rates have decreased by 5% to 20% during acute attacks.


Identifying the things that trigger an AIP attack will be a big part of learning to cope with AIP. For example, you might need to make some lifestyle changes and have regular heme infusions.

While it can be overwhelming to hear that you have a rare disease, you don’t have to go through the process of learning to live with it alone. Several organizations offer resources and support that are specific to AIP, including:


Acute intermittent porphyria (AIP) is one of a group of rare conditions that can affect the nervous system and skin. While management of the condition has improved greatly over the last few decades, it can still be fatal if it’s not diagnosed and treated correctly and quickly.

A Word From Verywell

It can be hard to learn to live with a rare disorder like porphyria, and getting the right diagnosis and treatment for a rare condition can be even more difficult. However, you should rest assured that AIP is a manageable condition when it’s diagnosed and treated early.

If you have family members with some form of porphyria, you may want to talk to your doctor about genetic testing for AIP—especially if you have experienced symptoms.

Frequently Asked Questions

  • Is acute intermittent porphyria inherited?

    AIP can be inherited or acquired. However, not everyone who inherits the genetic mutation that causes AIP develops symptoms.

  • Can acute intermittent porphyria be cured?

    While treatments have improved a lot over the last several decades, there is still no cure for AIP or any other type or porphyria.

  • Do skin blisters develop with acute intermittent porphyria?

    There are some forms of acute porphyria that involve the skin, but AIP is not one of them. The symptoms of this type of porphyria are mostly neurological.

4 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. Acute intermittent porphyria.

  2. MedlinePlus. Porphyria.

  3. National Institute of Diabetes and Digestive and Kidney Diseases. Porphyria.

  4. Pischik E, Kauppinen R. An update of clinical management of acute intermittent porphyriaAppl Clin Genet. 2015;8:201-214. doi:10.2147/TACG.S48605

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