Ulceration is a passive process, and results from the molecular death caused by insufficient blood supply, insufficient nervous influence, impure quality of blood, or the presence of blood poison. Ulceration is very closely associated with inflammation, although the former may be independent of the latter, and consists of a progressive softening and disintegration of successive layers of the affected tissue. Ulceration generally begins in a process of chronic inflammation, and in such a manner that the death of the tissues only occurs when the tissues themselves have undergone cellular infiltration in consequence of the inflammatory changes. The loss of the integument leaves a red, raw surface, which bleeds easily, and which is covered with a tenacious, slimy matter. Very soon irregular cavities are formed in this surface, separated by red elevations with ragged edges. A thin, serous, bloody discharge exudes, with severe pain of a gnawing character. The ulcer then formed, and which has been defined as "a wound surface having no tendency to heal," or an "open sore," spreads more or less rapidly, and the surrounding integument is hot and swollen, and the disintegrated tissue is thrown off as extraneous matter. It originates from an excess in action of the retrograde changes over such as induce repair. Ulcers also originate from pustules that fail to heal after the pus escapes, but spread and maintain an acute inflammatory character. An ulcer may be circular, crescentic, irregular, in the form of a shallow or deep ring, or it may be tubular, forming a fistula.

The edges of an ulcer are either low or raised, hard (callous), soft, jagged, vertical, everted, or undermined, etc. Ulcers arising from persistent local irritation, as those of the oral mucous membrane, usually heal as soon as the affected parts are placed under favorable external circumstances. As long as the epithelium is preserved, the superficial inflammatory process in mucous membranes may be called catarrh. When suppuration of mucous membranes proceeds so far as to expose the substantia propria or corium, the diseased surface is known as an ulcer. The surface of an ulcer is covered with coarse granulations of a dark red color, while healthy granulations are cherry red in color. The ulcer granulations bleed readily. Age, sex, and occupation, are important factors in the etrology of ulcers, as age is characterized by diminished physical power and vital resistance, and retrogressive tissue changes. Ulcers are three times as prevalent among men as among women: they are also more prevalent among the laboring classes, owing to a greater degree of exposure to injuries, and also to a greater neglect of personal cleanliness. Ulcers are classified according to their origin, such as the non-infectious and the infectious. The non-infectious comprise those caused by friction, pressure, or other mechanical injuries, chemical irritation, enervation, impaired nutrition, and obstructed local circulation.

Ulcers are also classified as inflamed, irritable, fungous, hemorrhagic, torpid, callous, corroding, perforating, phagedenic, and malignant. An inflamed ulcer is characterized by swollen edges, surrounding skin very tender, dense and shining, and the base and surrounding parts more or less acutely inflamed. The irritable ulcer is characterized by abrupt edges showing no tendency to cicatrize, and extreme tenderness or sensitiveness. The fungous ulcer is characterized by an exuberant growth of granulations. The hemorrhagic ulcer is characterized by a tendency to bleeding upon the least provocation, and is common to scurvy. Torpid ulcers are those which manifest no disposition of activity in any direction. Callous ulcers are characterized by a dirty, granulating surface covered with thin, muco-purulent pus, and prominent edges. Corroding ulcers are destructive, progressively, of soft tissues, beginning as a cutaneous disease, which becomes a boil and afterward an ulcer. Perforating or round ulcers are peculiar to the stomach, and caused by local obstruction of its blood vessels. Phagedenic ulcers spread rapidly, with great local irritation, and loss of tissue. Malignant ulcers are characterized by a rapid, spreading course, with perforation of soft parts, and resulting in gangrene and sloughing, and necrosis of bone.

The process of healing in ulcers is brought about by granulation and cicatrization, the devitalized parts separating from the living parts in the form of a thin, ichorous discharge, the exudates beneath and about the walls of the ulcer becoming vascularized and loops of capillary vessels forming and growing toward the surface. Numbers of leucocytes cluster around these capillary loops, and thus a healthy surface is formed which discharges a creamy pus-laudable pus.

Cicatrization is a process of skin-growth which covers over the new granulation tissue, the surrounding surface of skin or membrane sinking to a level with the granulations and the edge of the ulcer undergoing change in consistence and color, and the epithelial cells undergoing segmentation, and growing toward the centre of the ulcer, which is indicated by a blue film. At the same time the ulcer is contracting, and continues for a considerable period, and often causes great deformity.

The cicatrix is different from the original substance, having neither nerves, glands, lymphatics, nor hair, and when injured is prone to ulcerate.

The causes of ulceration are divided into predisposing and exciting, local and constitutional. The predisposing causes are changes in nutrition, peculiar dyscrasiae, and diatheses, the rapidity of the circulation, and injuries which are the most frequent causes, especially in the aged, the feeble, and those suffering from some constitutional diathesis, such as tuberculosis, syphilis, gout, diabetes, etc. Common ulcers are of the mucous membrane and skin and are never fatal except through septic infection.

Treatment

The treatment of ulcers is both local and constitutional, the cause of irritation being first removed and the inflammatory symptoms relieved. Rest of the affected part, cleanliness, hot antiseptic applications, elevation of limb when an extremity is involved. Stimulating remedies such as nitrate of silver, permanganate of potash, sulphate of copper, iodine, boric acid, balsam of Peru, and ichthyol, especially in indolent ulcers, and spraying with liquid air, are excellent. Chromic acid is useful in secondary syphilitic ulcers. Iodine and iodoform are serviceable in tubercular ulcers. Skin-grafting and plastic flap operations are sometimes resorted to for the purpose of closing extensive ulcers; also sponge-grafting to hasten the process of healing. The constitutional treatment of ulcers is directed to the systemic condition, when it is a predisposing cause, and appropriate remedies administered for its eradication. The strength must be supported by the use of tonics, and a vegetable diet recommended, and also abstinence from wine and malt liquors, etc.