Aphthous stomatitis is not considered to be true aphthous stomatitis by some sources. Some of these conditions may cause ulceration on other mucosal surfaces in addition to the mouth such as the conjunctiva or the genital mucous membranes. Resolution of the systemic condition often leads to decreased frequency and severity of the oral ulceration. Behçet's disease is a triad of mouth ulcers, genital ulcers and anterior uveitis. The main feature of Behçet's disease is aphthous-like ulceration, but this is usually more severe than seen in aphthous stomatitis without a systemic cause, and typically resembles major or herpetiforme ulceration or both. Aphthous-like ulceration
Aphthous stomatitis antigens, but this is unclear. Nicotine is also known to stimulate production of adrenal steroids and reduce production of TNF-α, interleukin-1 and interleukin-6. Smokeless tobacco products also seem to protect against aphthous stomatitis. Cessation of smoking is known to sometimes precede the onset of aphthous stomatitis in people previously unaffected, or exacerbate the condition in those who were already experiencing aphthous ulceration. Despite this correlation, starting smoking again does not usually lessen the condition. Various antigenic triggers have been implicated as a trigger, including L forms of streptococci, herpes simplex virus, varicella-zoster virus, adenovirus, and cytomegalovirus. Some people with aphthous