Aphthous ulcers are divided into two types: minor and major.
Minor aphthous ulcers appear as single discrete ulcers or in groups of two or more. They are characteristically found on the free movable oral mucosa rather than the attached mucosa. The formed ulcers are discrete with a white-yellow base, which is a fibrinous slough, and a distinct irregular border with a red halo. The lesions emerge in four stages.
- the first, or prodromal, stage, the individual will experience a tingling or burning pain in a clinically normal-appearing site;
- during the second, or preulcerative, stage, red oval papules appear and the pain intensifies;
- in the third, or ulcerative, stage, the classic ulcer appears; it will measure between 3 and 10 mm and may last 7 to 14 days.
- The fourth stage is the healing stage, in which granulation tissue followed by epithelial migration incurs healing without a scar.
Major aphthous ulcers are identical in their developmental stages and their general appearance except that they are larger (exceeding 10 mm), deeper (extending into the deep layers of the submucosa and into underlying muscle at times), and longer lasting (up to 6 weeks). Most individuals with major aphthous ulcers (formerly called Sutton major aphthae and before that incorrectly called periadenitis mucosa necrotica recurrens) harbor at least one or two lesions at all times.
The pathogenesis of aphthous stomatitis remains unknown. The theories are even more numerous than its suggested treatment schedules. The most plausible theory explaining most clinical observations is that of an immune-based leukocytoclastic vasculitis. In this theory, either autoantibodies to oral mucous membrane epithelium or circulating antibodies to the microorganism Streptococcus sanguis form antigen-antibody complexes within local vessel walls. These immune complexes together with complement initiate an intense cascade of inflammation mediated mostly by neutrophils. The secretion of cytopathic enzymes by neutrophils and other leukocytes causes the tissue destruction and necrosis of epithelium recognized as an aphthous ulcer.
Treatment of major aphthae.
Major aphthae, whether or not there is underlying disease such as HIV infection, may sometimes be so painful, persistent, and resistant to conventional treatment as to be disabling. Reportedly effective treatments include azathioprine, cyclosporin, colchicine and dapsone, but thalidomide is probably most reliably effective. Their use may be justified for major aphthae even in otherwise healthy persons if they are disabled by the pain and difficulty of eating. However, thalidomide can cause severe adverse effects and is strongly teratogenic, and, like the other drugs mentioned, can only be given under specialist supervision.