Epidermolysis bullosa

This describes a group of inherited blistering disorders which generally present early in life, although milder forms of the disease may not present until later in life. The autosomal dominant forms of epidermolysis bullosa (EB) require just one parent to have the faulty EB gene and the autosomal recessive forms require both parents to pass on an EB gene. This genetically determined group of conditions are characterised by the fact that the layers of skin do not adhere to each other normally, leading to splits between the layers of skin. Where these splits occur will determine the exact type of EB that an individual experiences (see Table 13.1).

Table 13.1 Summary of the types of epidermolysis bullosa.   Type of EB   Type of inheritance   Level of cleavage   Subtype   Location of blisters   Course of disease   EB simplex   Autosomal dominant   Within the basal cells of the epidermis   Generalised   Areas of trauma or friction   Intense levels of blistering starting as a neonate, which heal without scarring but can lead to severe incapacity continuing into adulthood.               Weber– Cockayne   Hands and feet following trauma   As above, although onset may be delayed until adolescence or adulthood.               Dowling Meara   Generalised severe form. Blisters present at birth, face, trunk and limbs. May involve mouth, GI and respiratory tracts   Very rare. Can be fatal to infants however may subside as the child grows up.   Junctional   Autosomal recessive   Within lamina lucida of the basement membrane zone       Widespread including mouth and pharynx   Eroded areas are widespread and hard to heal. Begin in neonatal period. Child often dies early due to sepsis.   Dystrophic   Autosomal recessive   Subepidermal with loss of anchoring fibrils       Widespread including mouth, pharynx and eyes   Blisters appear either from trauma or spontaneously and heal with scarring. If mouth/pharynx is involved, there can be problems with eating and eye scarring can lead to blindness. Nails and teeth are abnormal and squamous cell carcinomas may develop in atrophic areas.       Autosomal dominant           Smaller blisters generally appearing on limbs and areas of trauma   Less serious than recessive but scarring does occur and blistering continues throughout life.

Treatment
The treatment for all forms of EB focus on protecting the skin, minimising trauma and reducing the likelihood of infection. A syste matic review found that there was no reliable trial evidence for other interventions for treating EB (Langan and Williams, 2009). The more severe forms will also involve ensuring adequate nutritional intake and surgery to manage scarring which can cause ‘webbing’ to develop between fingers and toes. Thus, consideration must be given to soft furnishing, padded with sheepskins and soft clothes that do not rub or scratch. The child must always be handled with great care to minimise the amount of blistering caused by friction and trauma. For those who have the various forms of EB simplex, healing occurs without scarring and although this may take some time it does usually happen. Dystrophic forms of EB, particularly the recessive forms, will scar and require great care to be given to dressings and preventing infections.

The most important feature of any dressings that are used is that they are non-adherent and that they can stay in place for a number of days without requiring changing. Thus a secondary absorbent dressing may need to be placed over the primary non-adherent one. Dressings should not be stuck to the skin but secured with light bandages or cotton tubular dressings. If dressings do become stuck to the skin, it may cause less trauma to remove them whilst soaking in a bath during bathing (Ly and Su, 2008). Pain relief during dressing change is likely to be necessary; the choice of pain relief dependant on the level of pain. For some, Entonox may provide sufficient relief during the dressing change and avoids the problems of drowsiness associated with some pain relief.

Nutritional problems occur most commonly in the more severe forms of EB; junctional, dystrophic recessive and Dowling Meara. From an early age, neonates can develop blisters in their mouths, the lips and on the tongue which make feeding very painful. This may be helped by using teething gel and white soft paraffin on the lips, but oral feeding may in the end prove too difficult. In this instance, a long-term nasogastric tube should be used. Breast feeding is rarely successful as the child’s face becomes blistered whilst suckling and rubbing against its mother’s breast.

At all ages, EB sufferers are likely to have high calorific requirements due to the calories required for wound healing. This in combination with the difficulty of eating orally can mean that maintaining adequate nutrition is extremely challenging. Gastrostomy feeding may be necessary.

Physiotherapy will be helpful for those with dystrophic recessive EB in order to help minimise the contractions caused by scarring.

EB in all its forms can be a distressing condition, particularly as it occurs so early in life and as there is little effective treatment, only symptom management. It is important that an accurate diagnosis is made early on so that the parents know what to expect by way of disease severity. For those with the recessive form of the condition there is unlikely to have been any previous experience of the disease. It is important that parents have the opportunity to discuss the likelihood of having subsequent children with the disease, with a genetic counsellor. Prenatal diagnosis is possible.