Angina bullosa haemorrhagica
|Angina bullosa haemorrhagica|
|Classification and external resources|
Angina bullosa haemorrhagica is a condition of the mucous membranes characterized by the sudden appearance of one or more blood blisters within the oral cavity.:808 The lesions, which may be caused by mild trauma to the mouth tissues such as hot foods, typically rupture quickly and heal without scarring or further discomfort. The condition is not serious except in rare cases where a large bulla that does not rupture spontaneously may cause airway obstruction.
The blisters usually affect the palate or oropharynx and are often long lived to the extent that patients burst them for symptomatic relief. 
In one case, a male patient in his early 30s experienced recurring blood blisters under the tongue. These blisters, if allowed to grow beyond 5 or 6mm, would stretch and damage the mucous membrane, burst and later would always form a very painful and slow healing ulcer. He developed a technique of lancing nascent blisters with a clean straight pin while guiding the process in a mirror. The technique had to be performed quickly on first noticing the blister or the membrane would be irreversibly damaged and an ulcer would inevitably form. If caught in time, he reported that subsequent ulceration was entirely eliminated, but that the window of opportunity was very short (less than one minute). He therefore kept a pin in his wallet so that he could perform this technique as soon as he was aware that a blister was forming and he could excuse himself in social situations. The patient reported that eating hard, rough foods, such as potato or corn chips, seemed to exacerbate his condition, but that blisters had also formed from unknown etiology.
The condition is diagnosed on the basis of exclusion of other conditions and the typical presentation, particularly the constant presence of blood as the blister fluid. Angina bullosa haemorrhagica does not cause desquamative gingivitis