Epidermolysis bullosa simplex (localised)
Localised EBS is the most common form of EB. It causes painful blisters on the palms of the hands and soles of the feet that develop after mild or moderate physical activity, such as walking, gardening or playing sport.
Blisters can also develop on other parts of the body, such as the buttocks or inner thighs, after the skin has rubbed during activities like cycling.
Excessive sweating can make the blisters worse, so localised EBS is often more noticeable during the summer. The blisters usually heal without scarring.
Symptoms are usually noticed in early childhood, although mild cases may go undiagnosed until the early teens.
Some adults with localised EBS may experience thickening of the skin on their palms and the soles of their feet, as well as thickened fingernails and toenails.
Epidermolysis bullosa simplex (generalised intermediate)
In this form of EBS, blisters can form anywhere on the body in response to friction or trauma. The symptoms are usually more troublesome during hot weather.
There may be mild blistering of the mucous membranes, such as the inside of the nose, mouth and throat.
Scarring and milia (small white spots) may occur on the skin, but this is uncommon.
The symptoms usually begin during birth or infancy. As with localised EBS, adults may experience thickening of the skin on their palms and the soles of their feet, as well as thickened fingernails and toenails.
Epidermolysis bullosa simplex (generalised severe)
This form of EBS is the most severe type, where children have widespread blistering. In the most severe cases, a child can develop up to 200 blisters in a single day.
The widespread blistering can make the skin vulnerable to infection and affect an infant's normal feeding pattern, which means they may not grow and develop at the expected rate.
Painful blisters on the soles of the feet can affect an infant's ability to walk and may mean they start to walk later.
Blisters can also develop inside the mouth and throat, making eating – and sometimes speaking – difficult and painful.
Thickening or loss of the fingernails and toenails is another common symptom.
The symptoms usually develop at birth, but the blistering gradually improves as the child gets older, so adults may only experience occasional blistering.
But it's common for the skin of the palms and soles to become progressively thicker with age, and this may make walking or using the hands difficult or painful.
Junctional epidermolysis bullosa (generalised intermediate)
Generalised intermediate JEB causes widespread blistering of the skin and mucous membranes.
Blistering of the scalp is common, and may lead to scarring and permanent hair loss.
Other common symptoms include:
- slow-healing injuries, especially of the lower legs
- scarring of the skin
- deformity or loss of fingernails and toenails
- pigmented (coloured) areas of skin that look like large, irregular moles
Tooth enamel isn't properly formed, which means teeth may be discoloured, fragile and prone to tooth decay.
The mouth is also frequently affected by blisters and ulcers, which may make eating difficult.
Some patients also develop problems with their urinary system, such as blistering or scarring of the the tube that carries urine out of the bladder (the urethra).
The symptoms usually develop at birth or shortly afterwards and can improve with age.
As adults, people with this form of EB have an increased risk of developing skin cancer, so regular review by a skin specialist (dermatologist) familiar with EB is recommended.
Junctional epidermolysis bullosa (generalised severe)
This is one of the most severe types of EB, although it's extremely rare.
Generalised severe JEB causes widespread blistering of both the skin and the mucous membranes.
In particular, the following areas of the body are affected by blistering and persistent ulcers:
- the genitals and buttocks
- around the nose and mouth
- the fingertips
- the toes
- the neck
- inside the mouth and throat
- the eyes
Complications of generalised severe JEB are common and include:
Because of these complications, the outlook for children with generalised severe JEB is very poor.
Around 40% of children with the condition won't survive the first year of life, and most won't survive more than 5 years.
Sepsis and lung failure (caused by blistering and narrowing of the airways) are the most common causes of death.
Dystrophic epidermolysis bullosa (dominant)
Dominant DEB causes blistering at places on the body that experience trauma (often the hands, feet, arms and legs), which usually results in scarring. Milia (tiny white spots) often form at the site of the blisters.
The nails will usually become thickened and abnormally shaped, or even lost altogether. The mouth is often affected, which can make eating or cleaning teeth painful.
Some people with dominant DEB have mild symptoms with very few blisters, and the only sign of the disease may be misshapen or missing nails.
The symptoms of dominant DEB usually develop at birth or shortly afterwards, but may not occur until later in childhood.
Dystrophic epidermolysis bullosa (recessive, severe generalised)
Severe generalised recessive DEB is the most severe type of EB. It causes severe and widespread skin blistering that often leaves areas covered with persistent ulcers.
Repeated scarring to hands and feet can result in the loss of nails. Spaces between fingers and toes can fill with scar tissue, so hands and feet take on a mitten-like appearance.
Extensive blistering can also occur on the mucous membranes, particularly inside the:
- oesophagus (tube connecting the mouth and stomach)
- anus (bottom)
Tooth decay and repeated scarring in and around the mouth are both common. This can often cause problems with speaking, chewing and swallowing.
Repeated blisters on the scalp may also reduce hair growth.
As a result, many children with this form of DEB will have anaemia, malnutrition, and delayed or reduced growth.
The eyes can also be affected by blistering and scarring, which is painful and can lead to vision problems.
The symptoms of severe generalised recessive DEB are usually present at birth. There may be areas of missing skin at birth, or blistering developing very shortly afterwards.
People with this type of DEB have a high risk of developing skin cancer at the site of repeated scarring.
It's estimated more than half of people with severe generalised recessive DEB will develop skin cancer by the time they're 35.
Awareness of this problem and frequent check-ups (possibly twice a year) with a dermatologist are recommended.