Variegate porphyria: acute attacks, skin symptoms and staying safe

The BPA describes the porphyrias as a group of rare metabolic disorders that cause a build-up of certain chemicals in the body. All of them interfere with the way the body makes haem, a vital component needed to make haemoglobin and important proteins. In each type a different enzyme is affected, and porphyrins and their precursors can be overproduced and act as toxins. There are two general categories: the acute porphyrias, which mainly affect the nervous system, and the cutaneous porphyrias, which mainly affect the skin. NHS Tayside's porphyria service lists variegate porphyria among the four porphyrias that can cause acute attacks, with hereditary coproporphyria, acute intermittent porphyria and ALA dehydratase deficiency porphyria.

Variegate porphyria (VP) is unusual because it can cause both acute attacks and skin symptoms. The BPA says the condition cannot be cured, but symptoms and their severity vary from person to person.

The BPA describes typical features of acute attacks as severe pain in the abdomen, back, arms or legs, nausea, vomiting and constipation, low sodium levels in the blood, an increased pulse rate and blood pressure, confusion, convulsions and muscular weakness. NHS Tayside describes the main symptoms as gastrointestinal, cardiac (changes in blood pressure or heart rate), motor (muscle weakness or paralysis), psychiatric (anxiety, confusion, hallucinations) or central nervous system symptoms including seizures.

The BPA says acute attacks are caused by a build-up of the chemicals ALA and PBG, which damage nerves, and that about 1 in 75,000 people suffer from the acute porphyrias. Attacks are uncommon and often difficult to diagnose, which is why a person with a known diagnosis should carry information about it and tell clinicians. It says that although acute attacks can be very severe, nowadays they are rarely fatal and most people make a full recovery.

The BPA lists commonly prescribed drugs, illegal drugs, alcohol, dieting, stress, infections, viruses and hormonal fluctuations as things that often trigger acute attacks. It says that for people with an acute porphyria it is vital to ensure medicines are safe, and points to a "SAFE" drug list used by people with acute porphyrias. Everyone with VP is at risk of acute attacks, so it is vital to take a few simple precautions.

Practical steps include checking any new prescription, including over-the-counter medicines, against a current drug safety list with a pharmacist or the specialist service, avoiding crash diets and prolonged fasting, and getting prompt treatment for infections. These steps are general points that follow from the triggers the BPA lists.

The BPA explains that porphyrins can build up in the skin at certain times, causing sensitivity in areas exposed to sunlight, particularly the backs of the hands, face and legs, the scalp and the tops of the feet. Small blisters can appear; when they break they leave narrow brown hollows (often called ice pick lesions) that gradually fill up and disappear. VP can also cause small white dots (milia) that do not go away, and larger blisters that may be mistaken for porphyria cutanea tarda. Skin fragility is common and scrapes and cuts take time to heal.

For skin protection, it advises caring for the skin carefully: wash wounds and protect them with a dressing, wear gloves when scrapes are likely and avoid direct sunlight as much as possible, even sunlight passing through window glass. It recommends dark-coloured, densely woven clothing with long sleeves, light cotton gloves and a wide-brimmed hat, and says ordinary sunscreens are not very effective; the most helpful are thick, opaque preparations with high protection factors that block visible light, and Dundee cream is designed for skin porphyrias and must be prescribed by a GP.

Because VP is autosomal dominant, a parent with the gene has a 50% chance of passing it on in each pregnancy, boys and girls are equally likely to be affected, and the condition often appears to skip a generation because many carriers have no symptoms. The BPA has a dedicated page on testing and inheritance for families who want to know more, and a specialist service can advise on testing relatives.

Severe abdominal pain with vomiting, new weakness, confusion or a seizure in someone with known or suspected porphyria needs urgent assessment. Call 999 or go to A&E if symptoms are severe, and make sure the clinicians know about the porphyria diagnosis and safe-drug lists. The BPA is the national patient charity and lists UK centres of expertise on its website; your GP or specialist can refer you to the appropriate service.

Because the condition is rare, care is delivered through specialist porphyria services such as the NHS Tayside service, and a GP can refer you to the nearest one.