DEAR DR. DONOHUE: I went to the doctor because my ankles were swelling. He found I had pernicious anemia. I was so bad I had to walk with a cane. I have to take B-12 shots. Is that from now on? What will happen if I don't take the shots? And what about the ankles? - Mrs. S.M.

ANSWER: Ankle swelling can be a sign of any kind of anemia.I should explain pernicious anemia. It stems from a lack of B-12, essential in building red blood cells. The vitamin deficiency exists because the stomach lacks the substance vital for its absorption (intrinsic factor). That's why you need the B-12 shots.

With your body stores of B-12 replenished, the anemia should subside. I take it from your letter that you still have the ankle swelling. Remember, such swelling can be a separate problem and independent of the anemia. I am thinking of circulatory disturbance or heart and kidney problems.

There is even more motivation for getting the B-12 shots. Without B-12, nerves begin to deteriorate, as can the spinal cord. That can lead to significant difficulties for you. So please get your shots. Incidentally, Mrs. T.V. wants to know how pernicious anemia got its name. It's called pernicious because it develops slowly, unnoticed until dramatic symptoms arise, perhaps like S.M.'s ankle swelling (if there is that connection in her case).

DEAR DR. DONOHUE: Will you please tell C.P.S. (earlier writer) that our son at the same age had the exact problem. His teeth were fine. I too worried that his bad breath would make finding a job after graduation difficult. Later his uvula (a downward appendage from the soft palate) became swollen, and there was a polyp hidden behind it, where it was not visible. The polyp was taken out and he now is a very lovable and successful kid, and minus his bad breath. I know how that mother is suffering. - K.Z.

ANSWER: Mrs. Z adds some useful information to a previous item on bad breath. The polyp possibility should not be overlooked. Her son's doctor must have been a very thorough one indeed. I am amazed at how anxious my readers are to share their own tips on items appearing here.