Porphyria
A group of rare conditions where the body can’t finish making haem, the iron-containing part of blood. Building blocks pile up and cause either sudden attacks of severe pain (acute porphyrias) or skin damage from sunlight (cutaneous porphyrias).
Quick answer: Porphyrias are rare conditions affecting how the body makes haem. Acute intermittent porphyria (AIP) causes attacks of severe tummy pain, vomiting, fast heart rate and dark urine, often triggered by medicines, alcohol, fasting or hormones. A urine porphobilinogen test diagnoses an attack. Haem infusions treat attacks. Skin porphyrias cause blistering or burning in sunlight.
Acute intermittent porphyria (AIP)
How common. About 1 in 1,700 people carry a gene change for AIP, but most never have an attack. Symptomatic AIP affects about 1 in 100,000 people. Attacks mainly affect women between puberty and 50.
Causes. A faulty HMBS gene halves the activity of one enzyme on the haem production line, inherited from one parent. When the liver is pushed to make more haem, toxic building blocks (ALA and PBG) build up. Common triggers: some medicines (including some anti-seizure medicines, barbiturates and progestogens), alcohol, fasting or crash diets, smoking, infection, stress and the hormone changes before a period.
Symptoms of an attack. Severe, widespread tummy pain that’s often out of proportion to the examination, vomiting, constipation, a racing heart and high blood pressure, and red-brown urine that darkens on standing. Others: back and limb pain, muscle weakness, anxiety, confusion, low sodium and seizures. Severe attacks can cause paralysis. Skin isn’t affected in AIP.
How it’s diagnosed. A random urine test for porphobilinogen (PBG), ideally during symptoms, is the key test: in an attack it’s markedly raised. Genetic testing then confirms the type and allows family members to be tested. Per the American Gastroenterological Association, women aged 15 to 50 with unexplained recurrent severe tummy pain should be considered for screening.
Treating acute porphyria
Attacks are treated in hospital. Preventing triggers matters as much as treating attacks.
- AlwaysAvoid triggers and check every medicineUse a porphyria drug database before any new medicine, eat regularly, avoid alcohol and smoking, and carry a medical alert.
- Works
- Prevents many attacks
- Access
- Free databases (see sources)
- Watch for
- Don’t stop prescribed medicines without advice; ask about safe alternatives.
- During an attack · HospitalHaem infusion (haem arginate or hemin)Given into a vein daily for about 4 days. Plus pain relief (opioids such as morphine are safe), anti-sickness medicine, glucose, and stopping triggers.
- Works
- Rapidly lowers ALA and PBG and shortens attacks, especially when started early
- Access
- Hospital
- Watch for
- Vein irritation; repeated use can raise iron levels.
- Recurrent attacks · SpecialistGivosiranA monthly injection that switches down the liver enzyme that starts the overload. For people with frequent attacks (4 or more a year).
- Works
- In the ENVISION trial, attacks were 74% less frequent than with placebo (3.2 vs 12.5 a year)
- Access
- Specialist only; availability varies by country
- Watch for
- Liver and kidney test changes, injection-site reactions.
- Hormone-linked attacks · SpecialistHormone suppression or liver transplantMedicines that pause the menstrual cycle for attacks tied to periods. Liver transplant cures AIP and is kept for severe cases that don’t respond.
- Works
- Helps selected people
- Access
- Specialist only
- Watch for
- Significant side effects; specialist decision.
Cutaneous (skin) porphyrias
Porphyria cutanea tarda (PCT). The most common porphyria overall, usually starting in middle age. Fragile skin and blisters on sun-exposed areas, especially the backs of the hands, which heal with scars and tiny white cysts; extra facial hair. Triggers include alcohol, iron overload (including haemochromatosis), hepatitis C, smoking and oestrogen. Treated with regular venesection or low-dose hydroxychloroquine, plus treating the triggers. It doesn’t cause acute attacks.
Erythropoietic protoporphyria (EPP). Starts in childhood: intense burning, stinging pain within minutes of sunlight, usually without blisters, so it’s often disbelieved. Sun protection with clothing and visible-light protection is the mainstay (ordinary sunscreen doesn’t block the light that causes it); afamelanotide implants help some. Liver checks are needed, as a small number develop liver problems.
Living with it
- Wear a medical alert bracelet and carry a letter from your specialist.
- Check every new medicine, including over-the-counter and herbal products, with your pharmacist and a porphyria drug database.
- Avoid fasting and crash diets; eat regular carbohydrate, especially when unwell.
- Avoid alcohol and smoking.
- People with AIP should have yearly liver and kidney checks, and liver cancer surveillance from age 50.
See your GP if
- You have repeated attacks of severe tummy pain that tests haven’t explained, especially with dark urine
- A relative has porphyria (ask about family testing)
- Your skin blisters or scars easily on the backs of the hands
- Your child screams or cries with pain within minutes of sunlight
Get urgent help for severe tummy pain with vomiting, confusion, seizures, or new weakness in the arms, legs or breathing, especially with known porphyria or dark urine: call 000 (Australia) or your local emergency number. Tell the team you have, or may have, porphyria.
Outlook. Most people with an AIP gene change never have an attack, and most who do have only a few. People with frequent attacks now have better options. Long-term, AIP raises the risk of high blood pressure, kidney disease and liver cancer, so regular checks matter. Porphyria Awareness Week is in May: see our health days calendar. In Australia, Rare Voices Australia supports the nearly 2 million Australians living with a rare disease.
Common questions
What are the symptoms of acute intermittent porphyria?
Attacks of severe tummy pain, vomiting, constipation, a racing heart, high blood pressure, dark or reddish urine, anxiety or confusion, and sometimes muscle weakness or seizures.
What triggers a porphyria attack?
Some medicines, alcohol, fasting or dieting, smoking, infection, stress and hormone changes, especially before a period.
How is porphyria diagnosed?
Acute porphyria is diagnosed with a urine porphobilinogen (PBG) test, ideally during symptoms, then confirmed with genetic tests. Skin porphyrias are diagnosed with blood, urine and stool porphyrin tests.
Is porphyria the vampire disease?
That’s a myth. Some skin porphyrias cause sun sensitivity, but there’s no link to vampires, garlic or drinking blood.
Is porphyria hereditary?
Most types are inherited. In AIP, a parent with the gene change has a 50% chance of passing it on, but most carriers never have symptoms. PCT is often acquired rather than inherited.
What medicines are safe with porphyria?
Many medicines are safe, but some trigger attacks. Check every new medicine with a porphyria drug database, such as the one from NAPOS and EPNET or the American Porphyria Foundation, and with your doctor or pharmacist.
What colour is urine in porphyria?
During an acute attack urine may be red, brown or purple, often darkening when left in the light.
Evidence and more information
- Wang et al, AGA 2023: Clinical practice update on diagnosis and management of acute hepatic porphyrias
- Balwani et al, NEJM 2020: Phase 3 trial of givosiran for acute intermittent porphyria (ENVISION)
- NAPOS and EPNET: The drug database for acute porphyria
- American Porphyria Foundation: Drug database
- NHS: Porphyria
maladywise.com/porphyria/