There are 30 subtypes of EB identified (Fine, JD & Hinter, H. 2009), each of them has specific symptoms. The different types can be sorted in three main groups:  

·         Simplex: the fracture is produced in a superficial layer of the skin (the epidermis). The blisters heal without losing tissue. People affected improve in the course of time.

·         Junctural: the blisters appear in-between the external layer and the internal layer of the skin. The subtypes range from a lethal variety in the neonate period to other subtypes which improve in the course of time. This subtype is very frequent worldwide.

·         Dystrophic: the blisters appear in the deepest layer of the skin (the dermis). When they heal, the successive injuries provoke some withdrawals of the joints. That makes the movement more difficult. Some blisters could also appear in the mucous membranes: mouth, pharynx, stomach, intestine, respiratory and urinary tracts, eyelid and cornea.