ulceration

n. process of becoming an open sore or corrupting influence; process of causing an open sore or creating a corrupt condition

An ulcer (from Latin ulcus) is an open sore of the skin, eyes or mucous membrane, often caused, but not exclusively, by an initial abrasion and generally maintained by an inflammation, an infection, and/or medical conditions which impede healing. In other words, it is a macroscopic discontinuity of the normal epithelium (microscopic discontinuity of epithelium is called erosion). Other causes of skin ulcerations include pressure from various sources and venous insufficiency.
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Ulceration /ul·cer·a·tion/ 1. the formation or development of an ulcer. 2. an ulcer. ul·cer·a·tion n. 1. Development of an ulcer. 2. [more]Ulceration - Community and Resources

Noun
1. a circumscribed inflammatory and often suppurating lesion on the skin or an internal mucous surface resulting in necrosis of tissue
(synonym) ulcer
(hypernym) lesion
(hyponym) aphthous ulcer
2. the process of ulcer formation; the process of becoming ulcerated
(hypernym) organic process, biological process
(derivation) ulcerate

n. ulceration, process of becoming an open sore or corrupting influence; process of causing an open sore or creating a corrupt condition