Erythropoietic protoporphyria, or EPP, is a very rare form of Porphyria, a group of diseases where chemicals called porphyrins accumulate in the blood. This accumulation can cause a range of symptoms from the severe, such as abdominal pain, vomiting, and even brain and nerve issues, to less acute symptoms, such as skin irritation.
In EPP, the primary symptom is an adverse reaction to sunlight. Individuals with EPP will complain of severe pain, burning and itching in exposed areas after as little as 30 minutes of exposure to sunlight. In some cases, the skin can become red, inflamed and swollen. While these symptoms can be extremely uncomfortable, the condition is rarely fatal and as such is classified as a “non-acute” form of porphyria.
Usually, EPP first presents during childhood and even infancy, but in most cases it initially presents after the onset of puberty when hormone levels change drastically. Again, possibly in connection with changes in hormone levels, some women who suffer from EPP will notice a diminishing of symptoms during menstruation and pregnancy.
What causes EPP?
EPP is considered a genetic disease, meaning individuals are born with the tendency to develop the condition. What exactly predisposes some people to this buildup of porphyrins is not known at this time. The disease was first described in 1953 and has been the source of much speculation ever since.
The unique trait of being so adversely affected by sunlight has led many to link this condition to tales of vampires and werewolves and the rarity of the condition has made it a subject of much curiosity, leading to it being featured in popular TV shows such as House, MD.
While EPP primarily affects the skin, there have been a small number of cases that involve toxic levels of porphyrins in the liver, which can ultimately lead to liver failure. This particular feature of EPP is so rare that it is still not understood and research into it is ongoing. As a result, most doctors recommend regular monitoring of liver function in all EPP patients.
Are there any treatments available currently?
Unfortunately, there is no cure for EPP and most of the usual topical skin treatments to alleviate itching, such as calamine lotion and antihistamine ointments, are not effective. The most highly recommended course of treatment is avoiding exposure to sunlight and fluorescent lights. Protective clothing and sunlight blocking screens on windows can all be used to limit damage to sensitive skin. Most sunscreens are not effective, although those with a zinc oxide base that reflect sunlight have been known to work.
In 2014, an Australian pharmaceutical company received authorization by the European Commission to market a drug called Scenesse for the prevention of phototoxicity in adult patients. Fortunately, EPP is considered one of the least severe forms of porphyria, although that fact is of little consolation to the individuals who suffer from this painful condition.