Because of the depth of the lesion, hair follicles may be destroyed causing permanent alopecia and scarring on healing. Depigmentation is common due to basal layer melanocyte damage. The protective layer of the epidermis is lost and ulcerated skin or mucous membrane is prone to bacterial infection. If extensive areas are lost, systemic spread of infection, fluid and protein loss and dehydration may become complications. Spontaneous severe epithelial disruption is more likely to be the result of an internal disease process centred on the dermis, subcutaneous tissue or submucosa but ulceration can result from external factors such as thermal, radiation, chemical and mechanical including self trauma as well.
Ulcers vary in depth, shape and colour.
The shape and colour of the lesion may give a clue to the preceding insult. Ulcers may be described as dish shaped, punctate, craterous, shallow or deep. It often possible clinically to determine if the ulcerated surface is granulating or poorly healing. Shallow disruptions of the epithelial surface which are not severe enough to damage the basement membrane are referred to as erosions. In many cases it may be difficult to clinically distinguish the depth of these lesions but their presence indicated a disease process targetting epithelial or dermo-epithelial interface.