Doctor may suspect Epidermolysis Bullosa (EB) from the appearance of the skin but the following tests are needed to confirm the diagnosis—
When EB is suspected, a skin biopsy should be taken to confirm the diagnosis and identification of type of EB. The skin biopsy must be taken from a new blister. This is best performed on an area of skin where the physician has tried to induce a blister by rubbing the skin with a pencil eraser back & forth until epidermal separation is appreciated.
To perform the skin biopsy, the physician will use an anesthetic to first numb an area of skin. Then, the physician will take a small sample of skin from the edge of the blister for examination. Sometimes, 2 smaller samples may require to be taken. The skin samples must be processed for specific studies, immunofluorescence antigen (IFA) mapping and transmission electron microscopy (EM).
Immunofluorescence antigen mapping is performed to identify exactly where the blister has occurred and which proteins are involved (absent/diminished in amount). This is a specialized study which is generally done by a pathologist in a laboratory that specializes in this procedure.