DEAR DR. DONOHUE: A 55-year-old relative of mine was discovered to have a pericardial effusion after a routine heart scan. We have been told that this is usually the result of lupus, rheumatoid arthritis or a serious virus. Can you explain pericardial effusion and its cure? – Anon.

ANSWER: The pericardium is a double-layered sac that covers and protects the heart. The two layers of pericardium are separated by a small space that allows them to glide over each other with each heartbeat. A pericardial effusion is an outpouring of fluid that fills that space between the two pericardial layers.

Small pericardial effusions are discovered often accidentally when a person has a heart scan. Large pericardial effusions can disturb the heart’s beating. Such effusions can come from a viral infection of the pericardium – pericarditis. Pericarditis isn’t usually silent. It causes chest pain, and the person knows something is quite wrong. Pericardial effusions can also come from illnesses like lupus or rheumatoid arthritis, but those effusions are few and far between. Chest trauma, some medicines and radiation are other causes of these fluid collections. By far and away, the largest cause is idiopathic, meaning “cause unknown.”

Pericardial effusions that are small and don’t interfere with heart pumping can be left alone.

Large effusions that compromise heart action have to be drained.

Effusions between those extremes can often be treated with anti-inflammatory drugs like aspirin or indomethacin.

DEAR DR. DONOHUE: Please address seborrhea. What is it? What causes it? If it’s on the scalp, does it itch?

I probably have it. What’s a good shampoo for it? – I.S.

ANSWER: Seborrhea (seb-oh-REE-uh) or seborrheic dermatitis means a flow of oil. The oil comes from the skin’s or scalp’s oil glands. On the scalp, seborrhea is dandruff. It can also show up on the eyebrows, on the skin behind the ear, and on the facial creases that arc from the sides of the nose to below the mouth.

On the scalp, the skin might be oily or dry. It’s usually red and often itches. White dandruff flakes drop off it.

The cause is disputed, but could be a common fungus called pityrosporum.

Shampoos with zinc pyrithione can control the condition. Head & Shoulders is one brand name. Selenium sulfide also works. Selsun is a brand name for it.

Wash your hair daily with the shampoo and let it stay in contact with the scalp for a few minutes before rinsing it off.

If these products fail to end the problem, you’ll have to see your doctor for prescription shampoos.

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