Cutaneous (skin) porphyrias

The cutaneous (skin) porphyrias  can all give sensitivity to sunlight on exposed areas of skin. As with all porphyrias, the severity of the problem varies enormously. Sunlight should be avoided as much as possible. When avoiding sunlight is not possible, special sunblocks which block violet light can help. (In mild cases, high-factor sun cream with high-UVA protection may be enough.) Hats and clothing which cover up the skin are also recommended. See our skin safety page for more information.

We also have a leaflet on skin porphyrias

Cutaneous porphyrias comprise:

Porphyria Cutanea Tarda (PCT)

Erythropoietic Protoporphyria (EPP)

X-Linked Dominant Erythropoietic Protoporphyria (XLDPP)

Congenital Erythropoietic Porphyria (CEP)

 

Porphyria Cutanea Tarda (PCT)

Very rarely, PCT is inherited from one’s parents in the manner described for the acute porphyrias. However, most people with PCT did not inherit the disorder and will not pass it on to their children. Here, PCT is secondary to another condition. It may arise in some people because of drinking too much alcohol.

Most people with PCT acquire it (develop it) because an excess of iron in the liver, or the systems using iron, slow down the relevant enzyme. This is often triggered by alcohol (moderately heavy drinking), though some people are sensitive to iron supplements, artificial oestrogens (found in the pill HRT and prostate cancer treatment) or other drugs. Hepatitis C and HIV can also trigger it and haemochromatosis, another genetic condition, contributes in many cases.

People with PCT commonly develop skin problems. They will NEVER suffer an acute attack. Drugs do not hold the same danger for them as they do for people with acute porphyrias, although they should avoid alcohol.

PCT patients should avoid direct sunlight as much as possible, even sunlight that passes through window glass in a home or car. Protect skin from sunlight by wearing light cotton gloves, long sleeves and a hat. Not everyone will find this necessary or acceptable; adjust your clothing as it suits you.

Treatment is the same, whatever the origin - acquired or genetic – removal of any identified cause (trigger) where possible, and treatment, either with a drug (a low dose of chloroquine) or by venesection (removing blood, as for a blood donation), depending on the exact details of the person’s condition. The body then uses iron to make new red blood cells, reducing the stores in the liver, and the skin problems subside. The PCT may recur a few years after treatment has finished.
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Erythropoietic Protoporphyria (EPP)

This is a less common form of porphyria. Like the acute porphyrias it is an inherited disorder that is passed on from parents to their children. However, the inheritance of EPP is rather complex. It is currently believed that the faulty gene, paired with one particular ‘normal’ variant of the gene can cause EPP. In combination with other variants the EPP gene gives no problems.

What causes EPP?

In EPP, there is a shortage of a particular enzyme (ferrochelatase), which normally helps to convert protoporphyrin into haem by adding iron to it. This deficiency leads protoporphyrin levels to build up in the blood. As blood passes through the skin, the protoporphyrin absorbs energy from sunlight which sets off a chemical reaction that can damage the surrounding tissues and causes itching and burning.

The light that protoporphyrin absorbs is different from that which causes ordinary sunburn. Sunburn is usually caused by the shorter wavelengths of ultraviolet light (UVB), but in EPP the skin is more sensitive to longer ultraviolet wavelengths (UVA) and to visible light.

What are the symptoms of EPP?

EPP is rather different from the other cutaneous porphyrias, as it doesn’t usually cause blistering. In sunlight, the skin becomes very painful (itching and burning) and sometimes swells up slightly. Exposure to bright sunlight, for as little as a few minutes in the worst affected patients, causes burning pain in exposed skin, which may be so severe and persistent that it prevents sleep for several nights. The time of exposure to sunlight, before the pain starts, varies from one person to another, as does the time taken to recover once out of the light. It is important to remember that light does not always need to be direct – light reflected off water, sand or snow, or passing through window glass may also cause symptoms.

Some people get reddening of the skin, but many have nothing visibly wrong. Over time, the skin can thicken on the knuckles and there can be scarring on the face.

EPP normally develops in early childhood. An affected baby will often get fractious if taken outside, or put near bright lights, or by a window during daylight. The pain makes some scream. Even when brought indoors, the baby can still be fractious while the skin recovers.

What can be done to relieve the pain?

Patients usually attempt to relieve the pain by cold water or cold compresses. Some have suggested that fanned air helps relieve the pain to a certain extent.

What about treatment?

Unfortunately, there is no easy treatment.

Mostly it is a matter of: avoiding being out in the sun, under bright artificial light or close to a window (tinted film can be attached to windows, very useful in cars); covering up with a hat and light-dense clothing when outside; and using a special sunblock cream (e.g. Dundee cream). Sun block can be mixed with normal cosmetics to get a more realistic colour.

Please see our skin safety page for further information on sunscreens, light protective clothing and window films.

Beta-carotene: Some people respond to high doses of beta-carotene, which is available on prescription. The capsules are taken by mouth and may turn the skin slightly orange. Self treatment is not recommended as foods and some supplements may contain chemicals dangerous in the high doses needed. This medicine is considered to be safe, but may cause tummy upsets in some people. Studies showed some health benefits, eg fewer strokes, but also increased risk  of lung cancer in smokers.

Phototherapy: phototherapy involves exposure to artificial ultraviolet light, usually for a few times a week for a few weeks in the spring to allow the skin to thicken slightly and develop a tan. This acts as a natural sunblock and may improve tolerance to sunlight. Please see your porphyria specialist/dermatologist for more information on this treatment.

Clinuvel trials: Clinical trials are currently being undertaken by a company called Clinuvel. The trials are currently in the third phase and so far appear to be delivering positive results. Afamelanotide (trade name SCENESSE®) increases the levels of melanin in the skin and therefore shields against UV radiation (UVR) and the visible light in sunlight that triggers acute photosensitivity. The drug is delivered by a small subcutaneous dissolving implant. Increased pigmentation of the skin appears after two days and lasts up to two months.

Around 100 patients were given either Scenesse or a placebo (12-month period) and were asked to complete a diary of pain/sun exposure. The individual daily pain scores appear to be significantly lower in patients receiving Scenesse compared to those receiving the placebo. The trial results are due to be finalised in the next few months; we will keep you updated on further information.

Other issues

EPP does not cause acute attacks, so there is no need to stick to the “safe” drugs list. However, it is not advisable to drink excessively, as the combination of alcohol with EPP can affect the liver. Annual blood tests are needed to monitor the liver, as a few people (around 5%) develop liver problems.

Due to the lack of sunlight, EPP patients can suffer from a vitamin D deficiency, so this should be monitored.

Please see our other publications page for links to the British Association of Dermatologists leaflet on EPP and a link to Clinuvel’s information.
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X-Linked Dominant Erythropoietic Protoporphyria (XLDPP)

Despite being clinically similar to EPP in that both conditions cause phototoxicity, XLDPP is caused by activation of a gene which leads to overproduction and accumulation of the phototoxic enzyme protoporphyrin IX (PPIX) in the blood.

In terms of symptoms, please see the EPP section for more details.

Congenital Erythropoietic Porphyria (CEP)

This is the rarest of the porphyrias. It is primarily a skin condition and uniquely is inherited as a recessive condition. That means that both parents are asymptomatic carriers.

As this is such a rare disorder, data is very scarce regarding clinical traits and the resulting impact on quality of life for its sufferers.

Patients with certain gene mutations have a late onset of the condition and are able to manage their lives successfully with photoprotection. These patients regard the impact of CEP on their quality of life to be minimal. However, those who have other gene mutations develop early onset of the condition and their quality of life is severely impaired. They suffer with a wide array of chronic symptoms including severe photosensitivity to all visible light, photophobia, photomutilation, blindness, haemolytic anaemia and osteoporosis, among others.

For some, bone marrow transplantation can be successful; however this treatment is associated with severe complications. Although research is still ongoing, all CEP patients, including those with milder versions, should be regularly monitored for complications and encouraged to protect their skin and eyes at all times from visible light.

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