Global Porphyria Day Date in the current year: May 18, 2025

Porphyria is an umbrella term for eight disorders caused by a deficiency of one of several enzymes involved in the production of heme, a component of hemoglobin that helps bind oxygen in the blood. This deficiency results in a reduced amount of heme and a buildup of chemicals called porphyrins in the body, which can affect the nervous system or skin.

There are eight types of porphyria, depending on the enzyme involved: aminolevulinate dehydratase deficiency porphyria, acute intermittent porphyria, congenital erythropoietic porphyria, porphyria cutanea tarda, hereditary coproporphyria, harderoporphyria, variegated porphyria, and erythropoietic protoporphyria. Most are genetic, but porphyria cutanea tarda (PCT) can be acquired (sporadic). Sporadic PCT is a recognized complication of hepatitis C.

Each type of porphyria falls into one of two groups: acute and chronic. Acute porphyrias primarily affect the nervous system and cause episodes called acute attacks. These attacks are usually characterized by abdominal pain, vomiting, high blood pressure, and rapid heartbeat. Severe episodes can lead to neurological complications such as muscle weakness, seizures, and even coma.

Non-acute (chronic) porphyrias primarily affect the skin and manifest as skin diseases caused by the accumulation of excess porphyrins in the skin. Two types of chronic porphyria cause increased photosensitivity of the skin, with sun exposure causing pain, burning, and occasionally redness and swelling of the skin. Two other types cause increased skin fragility, blistering and erosions (open sores) in sun-exposed areas of the skin.

Treatment of porphyrias depends on the type and symptoms. Treatment of chronic porphyrias usually involves avoiding sun exposure, while treatment of acute porphyrias may include a high-carbohydrate diet (carbohydrates slow the accumulation of porphyrins), intravenous carbohydrates for severe attacks, heme analogs, and medications to treat symptoms such as pain and nausea.

Global Porphyria Day is coordinated by the Global Porphyria Advocacy Coalition (GPAC), an umbrella organization of national porphyria patient groups from around the world representing all types of porphyria. Its main goal is to educate the public about porphyria and to advocate for better access to diagnosis and treatment.

There are many ways to get involved with Global Porphyria Day. You can learn more about the different types of porphyria and share what you’ve learned with others, wear purple to show support for porphyria patients and start a conversation, contact your local government to have a landmark lit in purple on May 18, donate to an organization that helps porphyria patients or funds research, and spread the word on social media using the hashtags #GlobalPorphyriaDay and #PurpleForPorphyria. If you have porphyria and feel comfortable sharing your experience with the disease, you can share your story using the hashtag #MyPorphyria.