About bullosa hereditaria

What is bullosa hereditaria?

Epidermolysis bullosa (EB) is a genetic skin disorder characterized clinically by blister formation from mechanical trauma. There are four main types with additional sub-types identified. There is a spectrum of severity, and within each type, one may be either mildly or severely affected. EB ranges from being a minor inconvenience requiring modification of some activities, to being completely disabling and, in some cases, fatal.

Friction causes blister formation. Blisters can form anywhere on the surface of the skin, within the oral cavity and in more severe forms may also involve the external surface of the eye, as well as the respiratory, gastrointestinal and genitourinary tracts. In some forms of the disease, disfiguring scars and disabling musculoskeletal deformities occur.

Currently, there is no cure for EB. Supportive care includes daily wound care, bandaging, and pain management as needed.



What are the causes for bullosa hereditaria?

Basement membrane zone 

Depending on the type of epidermolysis bullosa, blistering may occur in the top layer of skin (epidermis), the bottom layer (dermis) or the layer that separates the two (basement membrane zone).

Autosomal dominant inheritance pattern 

In an autosomal dominant disorder, the altered gene is a dominant gene located on one of the nonsex chromosomes (autosomes). You need only one altered gene to be affected by this type of disorder. A person with an autosomal dominant disorder — in this case, the father — has a 50% chance of having an affected child with one altered gene (dominant gene) and a 50% chance of having an unaffected child with two typical genes (recessive genes).

Autosomal recessive inheritance pattern Open pop-up dialog box Close Autosomal recessive inheritance pattern Autosomal recessive inheritance pattern

To have an autosomal recessive disorder, you inherit two changed genes (mutations), one from each parent. These disorders are usually passed on by two carriers. Their health is rarely affected, but they have one changed gene (recessive gene) and one unaffected gene (dominant gene) for the condition. Two carriers have a 25% chance of having an unaffected child with two unaffected genes (left), a 50% chance of having an unaffected child who also is a carrier (middle), and a 25% chance of having an affected child with two recessive changed genes (right).

Epidermolysis bullosa simplex 

Epidermolysis bullosa simplex usually becomes apparent at birth or during early infancy. It's the most common and least severe type. Blistering may be relatively mild with epidermolysis bullosa simplex.

Dystrophic epidermolysis bullosa 

Dystrophic epidermolysis bullosa generally becomes apparent at birth or during early childhood. More severe forms of dystrophic epidermolysis bullosa can lead to rough, thickened skin, scarring, and disfigurement of the hands and feet.

Epidermolysis bullosa is usually inherited. The disease gene may be passed on from one parent who has the disease (autosomal dominant inheritance). Or it may be passed on from both parents (autosomal recessive inheritance) or arise as a new mutation in the affected person that can be passed on.

The skin is made up of an outer layer (epidermis) and an underlying layer (dermis). The area where the layers meet is called the basement membrane. The various types of epidermolysis bullosa are largely defined by which layer the blisters form in.

The main types of epidermolysis bullosa are:

  • Epidermolysis bullosa simplex. This is the most common form. It develops in the outer layer of skin and mainly affects the palms and the feet. The blisters usually heal without scarring.
  • Junctional epidermolysis bullosa. This type may be severe, with blisters beginning in infancy. A baby with this condition may develop a hoarse-sounding cry from continual blistering and scarring of the vocal cords.
  • Dystrophic epidermolysis bullosa. This type is related to a flaw in the gene that helps produce a type of collagen that provides strength to the pig-skinlike dermis layer of the skin. If this substance is missing or doesn't function, the layers of the skin won't join properly.



What are the treatments for bullosa hereditaria?

If lifestyle changes and home care don't control the signs and symptoms of epidermolysis bullosa, treatments may include medications, surgery and rehabilitation. The condition often progresses despite treatment, sometimes causing serious complications and death.

Medications

Medications can help control pain and itching and treat complications such as infection in the bloodstream (sepsis). The doctor may prescribe oral antibiotics if the wounds show signs of widespread infection (fever, weakness, swollen lymph glands).

Surgery

Surgical treatment may be needed. Options sometimes used for this condition include:

  • Widening the esophagus. Blistering and scarring of the esophagus may lead to esophageal narrowing, making eating difficult. Surgical dilation of the esophagus can relieve this and make it easier for food to travel from the mouth to the stomach. Risks include esophageal perforation.
  • Placing a feeding tube. To improve nutrition and help with weight gain, a feeding tube (gastrostomy tube) may be implanted to deliver food directly to the stomach.
  • Grafting skin. If scarring has affected the function of the hand, the doctor may suggest a skin graft.
  • Restoring mobility. Repeated blistering and scarring can cause fusing of the fingers or toes or abnormal bends in the joints (contractures). The doctor may recommend surgery to correct these conditions, particularly if they interfere with normal motion.

Rehabilitation therapy

Working with a rehabilitation specialist (physical therapist, occupational therapist) can help ease the limitations on motion caused by scarring and contractures.

Potential future treatments

Researchers are studying better ways to treat and relieve the symptoms of epidermolysis bullosa, including:

  • Gene therapy
  • Bone marrow (stem cell) transplantation
  • Protein replacement therapies
  • Cell-based therapies



What are the risk factors for bullosa hereditaria?

Having a family history of epidermolysis bullosa is the major risk factor for developing the disorder.



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