DEAR DR. DONOHUE: How important is potassium? Mine is on the low side, and I’ve been told to drink orange juice. I’ve never missed a morning without orange juice. What else can I do? – K.O.

ANSWER: Potassium is a very important mineral. It keeps nerves firing, the heart beating and muscles contracting. It figures into blood pressure control. It prevents bone loss, and it stops kidney stones from forming. Potassium can blunt the effect of salt (sodium) on blood pressure. It lessens the chances of stroke.

Too little potassium brings on muscle weakness, changes the ECG patterns and can alter the heartbeat. Long-standing deficiencies lead to kidney failure. Markedly low levels paralyze muscles, but that is a distinct rarity.

Rather than searching for what to eat and drink to raise potassium, the more important search is finding what’s making it low. One of the most common causes is diuretics. Are you taking a water pill for blood pressure control? Kidney diseases, changes in the body’s acid balance, diarrhea and adrenal gland disorders also lead to potassium losses.

When a cause is found and eliminated, the problem is solved.

When there’s a potassium deficiency and no cause is found for it, then a potassium supplement is the fastest way to right the situation. If the deficiency is not great, diet can restore the deficit. The daily potassium requirement is 4,700 mg. One cup of orange juice provides 500 mg; 10 dried figs have more than twice that amount; a baked potato with skin weighs in with 800 mg, and a sweet potato at 700. Beans, salmon, halibut, brussels sprouts, dairy products, most citrus fruits and bananas supply good amounts.

You should not be left to your own devices to solve this problem. Find out how low your potassium is and press your doctor to answer why your levels have dropped.

DEAR DR. DONOHUE: I have a number of what I call icicles dangling from my neck. One constantly gets caught in jewelry and bleeds. What are these things? Can I safely cut them off? – L.N.

ANSWER: I’m sure you’re speaking of skin tags. At least a quarter of adults have one or more of them. They’re most commonly found under the arms or on the neck. No one knows what causes them.

They aren’t cancer and they don’t lead to major trouble, except that they sometimes get in the way, as yours do.

From time to time, there appear medical articles that make an association between skin tags and terrible things, but never has any of those dire predictions been proven. At one time, they were said to be a sign of colon polyps. Today not many subscribe to that statement.

If they’re bothering you, have your doctor snip them off. It’s safer than doing that on your own. You might provoke an infection or bleeding that’s hard to stop.

DEAR DR. DONOHUE: What does head ringworm look like? I think my daughter has it. How do I go about proving what it is? How is it treated? – G.R.

ANSWER: Scalp ringworm – tinea capitis – has many appearances. Most frequently it starts out as a small bald patch about the size of a dime. The patch increases in size. Involved scalp is usually red and sometimes has a crust on the surface. Itching is common.

Children are the usual victims. Their oil glands do not have substances that stop scalp ringworm fungus from taking hold. Those substances appear after puberty.

Children can get it from another child, from resting their heads against seats or cushions that have the fungus, from sharing hats, combs or brushes with an infected child or from pets.

Griseofulvin, a medicine taken by mouth, is quite effective in eliminating it.

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.