Herlitz JEB is the most severe subtype of JEB. It is caused by mutations in the laminin-332 gene. Affected infants generally present at birth with severe, widespread erosions and blisters, although, in some cases, blistering at birth may be mild. After affected newborns are exposed to diapering, bathing and handling, the skin begins to blister and shear off, leaving large denuded areas. Erosions (sores) of the fingertips and slow or non-healing facial wounds are telltale indications of JEB, typically Herlitz JEB.
Commonly, blisters and slow or non-healing erosions are seen on these infants in the diaper area, around the nose and mouth, on the nail beds and the fingertips and toes, on the scalp and on the neck. Significant pain is reported by most parents and caregivers. Milia, scarring, alopecia and other scalp abnormalities and nail dystrophy are common. The development of excess granulation tissue is characteristic. Poor dental enamel, oral erosions and dental caries are common. Poor growth, anemia, and blistering and other problems involving the trachea/respiratory tract, intestines/gastrointestinal tract, eyes or genitourinary tract are common. Laryngeal blisters and resultant scars cause a hoarse cry during infancy. Tracheal blistering and scarring may cause occlusion of the trachea and suffocation if not recognized and treated.
Painful blisters and erosions may develop on the conjunctiva of the eye. Ectropion is another feature of JEB eye involvement where the eyelids are turned outward or pulled away from the eyes such that it becomes impossible to close the eyes. This is seen most often with the lower lids but also may be seen in the upper lids. With JEB, this finding occurs as a result of scarring. Surgical repair rarely is successful. Ectropion leaves the eyes susceptible to drying and vulnerable to foreign objects and dust particles, leading to further irritation and blistering. Artificial tears and ointments must be applied to the eyes regularly to prevent dryness and irritation.
Pseudosyndactyly may occur. The development of squamous cell carcinoma of the skin is uncommon but may occur; therefore, individuals with JEB should be evaluated annually by a dermatologist. Other types of skin cancer do not occur in association with Herlitz JEB. Osteopenia/osteoporosis has been reported in patients with JEB and may be due to malnutrition and malabsorption problems as well as decreased mobility and weight-bearing activities. Because of the severe involvement of the skin and internal organs, there is a significant risk of overwhelming infection (sepsis), malnutrition, dehydration and electrolyte abnormalities, tracheal occlusion and death during the first two years of life.