The patient
A 58 year old man noticed the sudden sensation of a swelling affecting his cheek. It was preceded by a burning pain and a look in the mirror revealed this blood blister. It wasn't bothering him that much until a friend suggested it might be leukaemia.
First instinct
There was quite a lot of metal work in the region of the buccal mucosa and so I assumed that this was probably caused by trauma. I suggested that he treat it conservatively and the blister would either break down or be absorbed.
Differential diagnosis
- Mucous membrane pemphigoid
- Dermatitis herpetiformis
The hidden clue
It was interesting that there was just one lesion. Dermatitis herpetiformis causes small vesicles and only occasionally affects the mouth. There were no lesions present in the usual places eg. extensor surfaces of elbows and knees. Pemphigoid, I felt, should cause more than one blister and the blisters would break down easily.
Getting on the right track
I hadn't seen this gentleman again, but I realised a few months later that I had the wrong diagnosis-not that it mattered, fortunately. I was reading a textbook of oral medicine and there the picture was. Angina haemorrhagica bullosa, usually affecting middle-aged and elderly people and associated with blisters around 1-3cm in size. The text stated that the soft palate is the most commonly affected area and the buccal mucosa is only affected occasionally. The blisters usually rupture and heal spontaneously with no treatment required.
