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Junctional epidermolysis bullosa

JUNCTIONAL EPIDERMOLYSIS BULLOSA

What are the aims of this leaflet?

This leaflet has been written to help you understand more about junctional epidermolysis bullosa. It tells you what it is, what causes it, what can be done about it, and where you can find out more.

What is junctional epidermolysis bullosa?

Junctional epidermolysis bullosa, also known as JEB, is a rare inherited (genetic) skin disorder. It is different from the other forms of epidermolysis bullosa, known as epidermolysis bullosa simplex and dystrophic epidermolysis bullosa. If you have JEB you will not develop one of the other types of epidermolysis bullosa at a later date.

The skin of those who have JEB is fragile and minor everyday knocks and friction cause blisters or sore areas. JEB may be mild, causing little more than inconvenience but it can sometimes be life-threatening. The blisters in JEB appear on birth or early in infancy. Babies affected by the most severe variant of JEB, referred to as Herlitz JEB, may not live beyond their first birthday. JEB is not an infection, it is not contagiousand it is not due to an allergy.

What causes junctional epidermolysis bullosa?

Two layers of skin, the epidermis and dermis, are held together by a variety of proteins, known as anchoring proteins. In those who have JEB, the structure of one or more of these anchoring proteins is faulty, weakening attachment of the epidermis to the dermis beneath. When the skin of JEB sufferers is subjected to friction and shearing forces, the epidermis and dermis separate, fluid accumulates in the gap between them and a blister forms. As the same anchoring proteins are found within the respiratory, digestive and urinary tracts, these organs are sometimes affected as well. Weakness of the anchoring proteins is caused by faults (mutations) in the genes bearing instructions for their assembly. A variety of such mutations have been identified in JEB. Some are common but others are specific to individual families.

Abnormalities have been identified in genes encoding three proteins known as laminin-332 (previously called laminin 5), type XVII collagen and α6β4 integrin.

Is junctional epidermolysis bullosa hereditary?

Yes, JEB is recessively inherited. Everyone has two sets of genes, one inherited from the mother and the second from the father. In recessively inherited disorders such as JEB, if both genes are faulty, no normal anchoring protein can be made and the skin is fragile. If only one of a pair of genes is abnormal, the second is usually able to produce enough normal anchoring protein for the skin to be unaffected. The parents of a child with JEB each have one normal and one abnormal gene but because they have healthy skin, parents are usually unaware that they carry a faulty gene until after an affected child is born. Each time parents of an affected child conceive, there is a 1 in 4 chance that the new baby will have fragile skin. Both males and females can be affected.

It is very unlikely that those with JEB will have affected children. This can only happen if the sufferer’s partner also has a fault in one of the genes controlling attachment of the epidermis to the dermis. The risk of this occurring is very small indeed.

As other more unusual inheritance patterns are possible, detailed genetic testing may be necessary before genetic counselling can be offered.

What are the symptoms of junctional epidermolysis bullosa?

The skin may appear normal at birth but blisters usually start to appear within hours or days. Occasionally, a newborn baby may have an absent area of skin or missing nails. Many babies with JEB have a characteristic hoarse cry. As blisters can be induced by even the most gentle skin contact, affected babies need careful handling. Special feeding techniques are often necessary to avoid inducing blisters on the lips or inside the mouth. Blisters can affect the surface of the eye, causing pain but leaving vision unaffected. Persistent vomiting during the early weeks of life may indicate narrowing of the outlet of the stomach which occurs in some forms of JEB. Babies with the most severe forms of JEB have generally very poor health.

There are less serious forms of JEB which do not shorten life. Specialised investigations are usually necessary to distinguish these from more severe JEB and other types of epidermolysis bullosa, as they may look very similar during the early months of life.

Like those with severe JEB, sufferers of non-lethal JEB experience painful blisters or open sores at sites of minor trauma to the skin. The inside of the mouth is often affected, causing pain during tooth brushing. As JEB can affect dental enamel, tooth decay occurs if dental care is neglected. Less frequent problems include bladder and kidney disorders and difficulty passing urine.

What does junctional epidermolysis bullosa look like?

Blisters vary in size. They are fragile and easily damaged leaving raw moist areas which require dressings. Occasionally a child with severe JEB may lose a large area of facial skin, leaving a raw moist surface. Some sufferers of JEB have rather sparse scalp hair. Nails may be normal but sometimes they become thickened or lost. Usually, JEB does not cause scarring but some variants do leave small pinkish-purple scars at sites of healed blisters. Scars gradually become more subtle with time. Sometimes small, temporary pin-head sized creamy harmless bumps, known as milia, arise on areas of skin where previous blisters have healed.

How will junctional epidermolysis bullosa be diagnosed?

It is usually necessary to remove a very small piece of skin from the affected baby. This is a simple procedure involving an injection of local anaesthetic. The skin sample will then undergo a number of detailed tests. Blood samples will be taken from the affected baby and from both parents for genetic analysis.

Can junctional epidermolysis bullosabe cured?

In the past 20 years, there has been exciting and rapid progress in the understanding of JEB but at the moment it cannot be cured. Several laboratories around the world are exploring strategies which they hope will ultimately lead to a cure.

How can junctional epidermolysis bullosa be treated?

Babies with JEB must be handled very carefully to avoid causing extensive blistering. Special feeding techniques may be necessary. Inevitably, some blisters and raw areas will still occur. The obstetric and paediatric teams caring for the newborn baby will contact DEBRA nurses and dermatologists who will organise appropriate investigations and will demonstrate how to care for the baby's skin.

Blisters should be burst with sterile needles and antiseptic creams should be used to prevent infection. Special non-stick dressings are available to protect the skin. Conventional adhesive tapes and plasters must be avoided as these will tear the skin when they are removed. Careful choices of clothing and lifestyle, to reduce friction and protect vulnerable areas of skin, will help reduce the number of new blisters. If the eyes are affected, simple lubricant ointments are helpful.

Self Care (What can I do)?

  • A healthy diet, regular dental checks (as soon as the first teeth appear), and careful skin care are important.

  • If you have an affected child, tell the teachers about JEB and make sure they understand that your child may not be able to take part in some of the more physical activities of the school curriculum.

  • If any form of surgery is necessary, it is important to warn the surgical team that their usual dressings and skin care regimes are unsuitable for JEB sufferers. They should also be warned that careful handling is required if an affected person is to be lifted. You should discuss your skin problems well before the date of a planned operation.

  • It can be helpful to carry a special wallet-sized information card giving details of JEB and the relevant precautions to be taken should you or your child need help in an emergency. These cards are available from DEBRA.

Where can I get more information aboutjunctional epidermolysis bullosa?

Advice and practical support for epidermolysis bullosa sufferers is available from DEBRA. This charity also funds epidermolysis bullosa research projects and produces a regular magazine with up to date information about new developments. DEBRA’s specialist nurses can visit people in their own homes and in hospital to demonstrate skin care regimes and they are available for telephone advice. If necessary, the nurses will visit schools to talk to staff and students. DEBRA staff can also offer advice and practical support to those applying for a disability living allowance and help with mobility.

DEBRA

DEBRA House

13 Wellington Business Park

Dukes Ride

Crowthorne

Berkshire RG45 6LS

Tel: 01344 771961

Fax: 01344 762661

Web (DEBRA-UK): www.debra.org.uk

Web: www.debra-international.org

Other useful websites:

http://www.ncbi.nlm.nih.gov/books/NBK1125/

http://ghr.nlm.nih.gov/condition/junctional-epidermolysis-bullosa

For details of source materials used please contact the Clinical Standards Unit (clinicalstandards@bad.org.uk).

This leaflet aims to provide accurate information about the subject and is a consensus of the views held by representatives of the British Association of Dermatologists: its contents, however, may occasionally differ from the advice given to you by your doctor.

This leaflet has been assessed for readability by the British Association of Dermatologists’ Patient Information Lay Review Panel

BRITISH ASSOCIATION OF DERMATOLOGISTS

PATIENT INFORMATION LEAFLET

PRODUCED AUGUST 2011

REVIEW DATE AUGUST 2014

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