The clinical hallmark of epidermolysis bullosa (EB) is the blistering of fragile skin, especially in areas that are prone to mechanical trauma. Other features that are prominent with EB include nail destruction, scarring of the skin and milia with very tiny and firm white papules that look like pustules or cysts.
In addition to these, there may be varying areas of hypo or hyperpigmentation on the body, confluent or localized thickening of the soles and palms and exuberant granulation tissue (commonly called ‘proud flesh’) in areas such as at the nape of the neck and around the mouth.
Other clinical manifestations that are less frequently seen include alopecia (hair loss), increased or decreased sweating, and flesh-colored or depigmented papules that appear predominantly on the lower trunk. It is important to note that some clinical features may be present or absent depending on the age of the patient. For example, during the first several months or even the first few years of life, there may be no nail dystrophy or exuberant granulation tissue. These tend to develop somewhat later in the course of the disorder.
While some features are age associated, others tend to be more subtype-specific. One such pathognomonic example is exuberant granulation tissue being seen almost exclusively in a subtype of EB called Herlitz Junctional epidermolysis bullosa (JEB-H), which is a severe form of the disease. The exuberant granulation tissue seen in JEB-H may resolve spontaneously in patients during adulthood. However, the likelihood of this is rare. Blistering in the various subtypes of the disease may vary. Some blisters are easier to burst in some subtypes as opposed to the others.
The complications associated with EB include vulnerability to bacterial infection due to the compromised skin barrier, which has the potential to cause sepsis if the infection enters the bloodstream and spreads throughout the body. Structural deformities can be seen in cases where severe forms of EB lead to pathological fusion of fingers and / or toes and joint contractures (abnormal bending). Difficulty in eating due to blistering of the upper digestive tract may cause poor appetite and resultant dehydration, malnutrition, and anemia. Symptoms in the lower digestive tract may cause constipation. Other oral manifestations include hypoplasia of the enamel, which tends to promote cavity development and loss of teeth.
More severe complications include blindness due to scarring of the cornea and an increased risk of squamous cell carcinoma with certain types of EB, such as dystrophic epidermolysis bullosa. The most significant complication of EB is stenosis of vocal cords, which may lead to obstruction of the airway and death. This is typically seen in the JEB subtype and may cause death of infants before their first birthday. An uncommon, but potentially fatal, complication is dilated cardiomyopathy that may also be associated with renal failure and is thought to be a result of micronutrient deficiencies.
The fragility of the skin is seen to worsen in warm conditions in all subtypes of EB except the EB-simplex subtype, in which there is reduction in blistering with fever. It is therefore advisable for patients with those subtypes adversely affected by heat to use coolers or air-conditioners during hot summer months. Also, the more extensive the blistering on the skin is, the greater the chance of extracutaneous areas such as the enamel and organs like the heart and kidney getting affected.
Reviewed by Susha Cheriyedath, MSc