DEAR DR. DONOHUE: I would greatly appreciate it if you would write an article on lupus. Thank you in advance for any information and help on this matter. – R.L.

ANSWER: Lupus is an example of an illness caused by an immune system that turns against its own body. It is, therefore, an autoimmune disease.

Usually it comes on between the ages of 20 and 45, and the preponderance of patients are women.

Lupus attacks many body organs and tissues. The skin can break out in a variety of rashes, but a common one is a redness of the cheeks and bridge of the nose. The skin is quite sensitive to sunlight, and exposure to it can often cause a worsening of symptoms.

Joints frequently become swollen and painful. The heart and the heart covering can be involved. Heart valves can become deformed, and inflammation of the pericardium (the heart covering) gives rise to chest pain. Lupus can attack nerves. The kidneys are often involved, with a resulting increase in blood pressure and a loss of protein in the urine.

The diagnosis of lupus is made by examining a patient for its typical signs and symptoms and through laboratory tests that show the immune system is acting up. Lupus patients often have an array of strange antibodies in their blood. Antibodies are the bullets of the immune system. One, called ANA (antinuclear antibody), is commonly found in lupus.

Today’s medicines can control lupus for most patients. More than 90 percent of lupus patients are still living 10 years after diagnosis, and 70 percent are living longer than 20 years. Such success in treating lupus was unheard of even a few short decades ago.

DEAR DR. DONOHUE: Last winter my wife started having pain in her left hip. The doctor diagnosed it as arthritis. Another doctor told her she had some arthritis but the main problem was iliotibial-band inflammation. He gave her a shot of cortisone and prescribed physical therapy. After three weeks the pain has returned. What information can you provide on this problem? – R.S.

ANSWER: The iliotibial band is a strip of dense tissue extending from the side of the hip to the side of the knee. One of its functions is to stabilize the knee.

Inflammation of this band is something that happens mostly to runners, from overuse. Most frequently, pain is felt alongside the knee, but it can be felt at the hip, too.

If time, physical therapy, anti-inflammatory medicines and the cortisone injections are not getting rid of the pain, it would be well worth your wife’s time to seek another opinion.

DEAR DR. DONOHUE: What can you tell me about Sweet’s disease? My 45-year-old daughter has it. She gets lesions on her arms, face and in her mouth. She has seen a number of “gists” – dermatologists, oncologists, gastroenterologists – without getting an answer. – L.K.

ANSWER: Sweet’s disease is also known as acute febrile neutrophilic dermatosis. It consists of rapidly enlarging, tender, red bumps 0.8 to 4 inches (2 to 10 cm) in diameter. They break out on the face, neck, chest, abdomen, back, arms and legs. Patients often describe them as burning. Canker sores may be part of the picture. Attacks last about three to six weeks.

Cortisone medicine can usually put an end to an attack. However, people can have multiple recurrences, and your daughter appears to be one of those unfortunate people.

The cause has not yet been discovered.

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.