Dominant dystrophic epidermolysis bullosa (DDEB) is a type of epidermolysis bullosa (EB), which is a group of rare inherited conditions in which the skin blisters extremely easily. DDEB is one of the milder forms of EB, although the severity is variable. Blisters may be present at birth, but typically appear during early childhood; occasionally they do not develop until later in life. Blisters often become more numerous and tend to occur over vulnerable sites such as knees, ankles, elbows and knuckles. In adulthood, they usually become less frequent and scars fade. Other signs and symptoms of DDEB may include dystrophic or absent nails, constipation, dental caries and swallowing problems. It is caused by genetic changes in the COL7A1 gene and is inherited in an autosomal dominant manner.