DEAR DR. DONOHUE: I am always tired and sleep way too much. I have no energy at all. My doctor thinks I might have chronic fatigue syndrome and says nothing can be done for it. Can you tell me something on this subject? — J.F.

ANSWER: Chronic fatigue syndrome, CFS, is an elusive illness without a specific test (no blood test, no X-ray, no scan) that proves a person has the illness. It’s also an illness whose cause hasn’t been resolved. It’s defined as debilitating fatigue lasting six or more months. One important aspect of the diagnosis is excluding all other illnesses known to cause fatigue. The number of those illnesses is legion. Depression, anxiety, anemia, blood pressure medicines, an underactive thyroid gland, adrenal gland insufficiency, pituitary gland problems, kidney failure, liver failure, hidden cancers, hidden infections such as tuberculosis, congestive heart failure, chronic obstructive pulmonary disease, rheumatoid arthritis, lupus and sleep apnea are only a few fatigue-causing conditions.

If those illnesses are excluded and the patient has fatigue plus a few other symptoms, then the diagnosis of chronic fatigue rests on solid ground. Those other signs and symptoms include low-grade fever, sore throat, painful neck and underarm lymph nodes, muscle weakness, muscle pain, an increased degree of fatigue after slight exertion, joint pain and disturbed sleep. Impaired memory and difficulty concentrating are two other signs. A person need not have all these signs, but having a few suggests CFS.

Chronic fatigue syndrome shares many symptoms with another elusive illness, fibromyalgia. CFS mostly occurs between the ages of 20 and 50, and more females than males suffer from it.

Things can be done for it. Antidepressant medication, taken for its ability to induce sleep, can restore normal sleep patterns. Graded exercise is helpful. Cognitive behavior therapy has lessened the grips of CFS for some. It’s therapy that tries to discover any underlying thought patterns that drain energy. The National Chronic Fatigue Syndrome and Fibromyalgia Association can provide you with other information. The Web site is www.ncfsfa.org.

DEAR DR. DONOHUE: My daughter has hepatitis C. She has been through treatment and is doing well. She read an article that stated hepatitis C turns into cancer. Now she thinks she will have cancer. Will you please write about it and let me know about the cancer connection? — G.G.

ANSWER: I looked at all my past articles on hepatitis C to make sure I didn’t write that. I didn’t. The facts are these: Up to 80 percent of those infected with the hepatitis C virus are infected for life. Of that number, around 20 percent develop cirrhosis of the liver 20 or more years after the initial infection. And of those who come down with cirrhosis, a small percentage go on to develop liver cancer. Looked at another way, the majority of hepatitis C patients develop neither cancer nor cirrhosis.

Neither complication is likely to happen to those who have been treated, as your daughter has.

DEAR DR. DONOHUE: I wrote to you a while ago for information on why my nose runs so much when I eat. You once had an article about this in the paper, but my paper was thrown away. Will you please repeat the information? — H.G.

ANSWER: The condition is called gustatory rhinorrhea, and I never dreamed it was such a common malady. Many letters arrive weekly asking about it.

Spicy, hot (temperature hot) foods often provoke a drippy nose. Less often, alcohol and cold foods bring it on. Avoiding these foods is one sure way to stop it from happening.

Sudafed, a decongestant obtainable without a prescription, taken half an hour before meals, often halts the dripping. Atrovent (ipratropium) Nasal spray and Astelin Nasal spray are two items that also can turn off a leaking nose. Both of these are prescription medicines. Don’t use medicine for all meals. Save the medicine treatments for social engagements or for other situations when a runny nose is a source of embarrassment.

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.