DEAR DR. DONOHUE: For the past year I have had outbreaks of hives on my face. I visited an allergy specialist and was told I tested positive for being autoimmune. The doctor took a blood sample, spun it down and then injected it into my skin. The skin showed an allergic reaction. Is this a reliable test? I was also tested for autoimmune diseases, and the results came back negative. I take antihistamines. I can’t find much about being autoimmune. Any information you have would be great. – A.M.

ANSWERS: Hive attacks are often caused by allergies, so an allergist is the doctor to turn to when having repeated hives. Sometimes, recurrent hive attacks are linked to other illnesses, like lupus (an autoimmune disease), thyroid gland malfunctions or even cancers, and those possibilities have to be considered. Lately, it’s been postulated that hives for which no cause can be found are the product of one’s immune system having gone amok.

The immune system is a hazy concept for most people. It consists of a number of cells and organs. Cells that make antibodies are part of the immune system. Antibodies are like missiles that take out threatening germs. Lymph nodes filter germs and foreign matter and are another part of the immune system. White blood cells, the body’s infantry, are a third arm of the immune system.

An autoimmune illness is one in which this defense network turns against its own body. In autoimmune hives, for example, the immune system makes antibodies that react with other body cells and cause a release of chemicals such as histamine that, in turn, bring on a hive attack.

Spinning down a tube of a patient’s blood and injecting into the patient’s skin the clear fluid from the top of the tube is one way of testing for autoimmune hives. A positive reaction shows that there are autoimmune antibodies in the blood.

Antihistamines are the standby for most hive attacks. If they can’t control them, then a combination of an antihistamine with either Tagamet or Cimetidine can be helpful. Those two meds control stomach-acid production. They do, however, also control histamine release, so they’re quite useful for resistant hives.

DEAR DR. DONOHUE: Are people who have had electroshock therapy at risk for early dementia or Alzheimer’s disease? – J.

ANSWER: People shudder when they hear “electroshock.” They’ve seen older movies in which administration of this therapy provoked violent convulsions. That’s not the case with EST today.

Now patients who have EST are anesthetized and given muscle relaxants. When the shock is given, there is no visible reaction, no muscle contraction and no violent movements. The patient is asleep.

EST is a valuable treatment when medicines and talk don’t bring a person out of a serious depression.

EST doesn’t cause brain damage. It doesn’t lead to dementia or Alzheimer’s disease. It can cause a temporary loss of memory.

DEAR DR. DONOHUE: I am 74. I have such problems with my feet. My toes and the bottoms of my feet are numb. Four doctors can’t tell me why. Can you? – A.S.

DEAR DR. DONOHUE: I have been very active and walk about 20 blocks every day. I have trouble with my feet. They burn or feel like pins and needles are going through them. I have used specially made insoles, but they haven’t worked. Have you any idea what could be causing this? – M.C.

ANSWER: Neuropathy is a reasonable guess for both of you. It’s a disruption of nerves and nerve transmission. It often starts with numbness and then progresses to feelings of burning, pins-and-needles or shock sensations.

A neurologist can tell you if neuropathy is the cause and what can be done for it. Even if you have seen one neurologist, see another. It can take time before a positive diagnosis is made.

Dr. Donohue regrets that he is unable to answer individual letters, but he will incorporate them in his column whenever possible. Readers may write him or request an order form of available health newsletters at P.O. Box 536475, Orlando, FL 32853-6475. Readers may also order health newsletters from www.rbmamall.com