Question: I was told eight years ago that I had Crohn's disease. I was treated for six months with sulfasalazine. It worked. I was fine. In fact, it was not until two weeks ago that I learned the disease is active again, so I'm back on medicine. I wonder if recurring Crohn's disease is cumulative, leaving the intestines more and more weakened. Also, how can I prevent recurrence.

- Mrs. G.M.

Answer: Crohn's disease is serious inflammation of the digestive tract anywhere along its length, from the mouth to the large intestine. The usual Crohn's target area is the ileum, the lowermost section of the small intestine.

Its cause remains unclear.

You can take some satisfaction from the fact that your Crohn's took an extended symptom-free hiatus. Such infrequency bodes well overall. The long interval between flares removes much of your concern, that of serious intestinal scarring and narrowing, the fate of others in whom Crohn's stays active for longer periods.

No one can offer 100 percent assurance, but I'd say you need not anticipate some of the severe consequences some Crohn's patients face. Those patients must beware the more common triggers of Crohn's episodes, including emotional stress, dietary indiscretion, intestinal tract infection and smoking.

Meanwhile, you can expect your sulfasalazine to keep any scarring and ulceration under control as it did in the past.

For more information, see the Health Letter report on the subject. To order a copy, write: Dr. Donohue - SR122, Box 5539 Riverton, NJ 08077-5539. Enclose $3 and a self-addressed, stamped (55 cents) No. 10 envelope.

Question: My husband had a heart attack traced to a blood clot. Later we were told he has something called "polycythemia rubra vera." Even though he was treated - with streptokinase - within hours, heart damage occurred. No symptoms, no other illnesses, now no warnings. He was a smoker but has quit. Please tell us more.

- Mrs. J.K.

Answer: Polycythemia rubra vera is overproduction of red cells by the bone marrow, which at the same time churns out an excess of other kinds of blood cells, causing a thickening that leads to inappropriate clotting. If that happens in a heart artery, a heart attack ensues, as it did in your husband's case.

Heart attack is not the sole consequence of the condition. Stroke occurs if a brain vessel is involved. And because the bone marrow produces plentiful but defective clotting cells, the patient might experience easy bleeding and bruising.

Generally, the outlook for the patient is much brighter today than even a few years ago, thanks to greater knowledge and treatments, including periodic blood removal and use of medicines such as hydroxyurea.

Question: What is primary polycythemia? It implies another kind (secondary) right?

- J.U.

Answer: I've been saving your letter for use when the opportunity presented itself.

The primary kind of polycythemia is that described above by its true name: polycythemia rubra vera.

The secondary kind is an overpopulation of blood cells due to other reasons. Secondary polycythemia can occur from the effects of high altitude or from smoking, for examples.