Xeroderma pigmentosum, also known as XP, is a virulent form of photosensitivity. It is actually an umbrella term for several diseases with a genetic cause that are inherited and lead to the formation of blisters on the skin after sun exposure.
It can sometimes have immediate symptoms, with the painful blisters emerging right after sun exposure. In other cases, it can initially look like a very bad case of sunburn, alongside severe erythema (skin inflammation). As an inherited condition, it can become active since birth or during the first years of life. It is possible for the first symptoms to only appear during childhood or even adulthood, but this is rare. It can also cause the skin to become brittle, scarred or discoloured.
Besides the skin, xeroderma pigmentosum can also appear on the eyes. It can be connected to some very serious diseases, such as skin cancer, serious handicaps, mental retardation or dwarfism. It appears to be also linked to the nervous system, since it disrupts it in some patients.
Since it has a genetic trigger, the disease is present since birth or starts very early during infancy. In many cases, kids only need a few minutes of sun exposure before developing signs of severe sunburn. The symptoms include strong inflammation and blisters that only heal after a few weeks. However, some children who have this condition can tan normally and not get burned immediately by the sun. A typical sign of xeroderma pigmentosum is the presence of freckles on the face, lips, arms and other areas exposed to the sun, before the age of two. It is extremely rare for healthy kids to have freckles so early in life, even if they have a sensitive skin type. The name xeroderma pigmentosum comes from the two other effects of this disease, which are xeroderma (dry skin) and irregular skin pigmentation (color).
An extremely dangerous side effect of xeroderma pigmentosum is that it significantly increases the risk of skin cancer. Kids who suffer from it lack the normal sun protection and about half of them already suffer from skin cancer before the age of ten. This is only the start, since most patients will experience multiple skin tumours. The most vulnerable areas are those exposed to the sun, especially the face, eyelids or lips. Some unusual locations where cancer can develop are the scalp, tip of the tongue or even the eyes. According to some researchers, xeroderma pigmentosum also increases the risk of brain cancer and other types of tumours. Combined with smoking, the disease makes lung cancer a lot more likely than normal.
People who suffer from xeroderma pigmentosum tend to have extremely sensitive eyes that can't resists UV radiation and hurt after sun exposure. The eyes become irritated, with visible red veins and their cornea, which is the transparent layer that covers the eyes, might get clouded. As a result, eye protection is required at all times. It is also possible for the eyelids to become thin or have an unusual shape, while eyelashes can simply fall off. These issues can severely harm vision. Xeroderma pigmentosum can not only cause eye cancer but also benign eye tumours.
About one in three patients with xeroderma pigmentosum also suffer from mental problems that can become more and more severe in time. These neurological issues have various effects, such as lack of coordination, inability to walk properly, seizures, movement difficulties, hearing loss, problems with talking or swallowing and the progressive loss of intellectual capacities. These issues become worse with aging.
There are usually three stages of this condition. In most cases, a baby's skin seems to be normal at birth. After around half a year, the first signs of xeroderma pigmentosum appear. Minimal sun exposure causes the skin to turn red, covered in freckles and scales. Dark spots with irregular shapes can also pop up on the skin. These issues are initially found only on the face and other areas with direct sun exposure but later begin to spread and expand to the legs or the neck. The trunk can also be affected but only in really serious cases. Some of the symptoms can regress during the winter, when sun strength is reduced.
Poikiloderma is the distinctive feature of the second stage, which is triggered by more exposure to sunlight. The skin is covered by an irregular pattern or patches with either a darker or a lighter color. The skin itself becomes thinner and a maze of blood vessels and spots are visible under its surface.
Finally, xeroderma pigmentosum can progress to the third stage, which leads to serious diseases such as skin cancer or actinic keratoses. These usually affect the face and other zones exposed to the sun and can develop even before the age of 4 or 5. People who suffer from xeroderma pigmentosum have a greatly increased risk of all forms of skin cancer, including melanoma, basal cell carcinoma or squamous cell carcinoma.
Eye complications are an extremely common side effect of the disease and occur in around 80% of all cases. Usually, the eyes are very sensitive to sunlight and get bloodshot, irritated or clouded after minimal exposure. The eyes are also prone to both benign and malignant tumours, as well as conjunctivitis.
Neurological issues are rarer and only affect about one in five patients. These can start at the end of childhood or during adolescence and become progressively more severe. Examples include dwarfism, late development, spasms, deafness or bad coordination.
Like all genetic diseases, xeroderma pigmentosum can't be cured. Doctors focus on countering the symptoms and try to prevent the more severe effects of this condition. Dermatologists are the ones who inspect the skin and eliminate all types of cancers or other dangerous growths. Eye problems are treated by an ophthalmologist, who is a specialized doctor.
All of the effects of xeroderma pigmentosum are caused by exposure to UV light. As a result, protecting the skin and eyes from this form of radiation is the best thing to do. People who suffer from this disease should apply sunscreen and wear sunglasses, long sleeves, long pants and gloves every time they go outside. They must be careful even when indoors and remain fully clothed, as well as close the windows at all times. Unlike normal children, those who suffer from xeroderma pigmentosum should be stopped from playing outside when the sun is up.
Halogen lamps and other types of interior lightning also produce UV radiation. It is very important to inspect and eliminate such sources from any indoor environment, even at work or at school. To prevent exposure to unknown indoor sources of UV light, xeroderma pigmentosum patients should always use sunscreen.
Several other measures can reduce the effects of xeroderma pigmentosum. These are constant medical examinations of the eyes and the skin, as well as tests that can detect neurological problems as early as possible.