DEAR DR. DONOHUE: Would you write about burning-mouth syndrome? My tongue has been burning for three months. It feels as though it has been scalded. Doctors don’t have much to say about it. – S.P.

ANSWER: Burning-mouth syndrome is a sensation that the entire mouth, or parts of it – the tongue or palate – are on fire. The sensation gets worse in the later afternoon and often interferes with sleep. It happens mostly to women who have undergone menopause, so many believe that the menopausal diminution of estrogen has something to do with it. Estrogen can’t be the sole answer, for it also happens to men.

When doctors or dentists examine the mouth and tongue, they can’t find anything that looks out of the ordinary.

In a few people, a cause for burning-mouth syndrome is found in conditions like GERD – heartburn. Stomach acid can find its way into the mouth and produce the burning sensation. Sometimes diabetes, iron deficiency, a lack of vitamin B-12 or a lack of folate, another B vitamin, has a hand in it. If saliva production is below par, burning mouth can result. For some, infection with the yeast candida is the source of trouble. These conditions are treatable.

Most cases, however, have no identifiable cause. These people have to be content with trying a variety of remedies, none of which is particularly satisfying for all. Because there is some evidence that defective nerve transmission might be involved, drugs used for neuropathy – nerve-induced pain – can be tried. Among those drugs are amitriptyline and gabapentin, both prescribed in low doses.

One home remedy is swishing cold apple juice in the mouth. Another is a mixture of ½ teaspoon of Benadryl elixir and ½ teaspoon of Kaopectate used as a mouthwash and then spit out.

If this is any solace to you, many people who suffer from burning mouth find that it vanishes in time, but that can take years.

DEAR DR. DONOHUE: All my life I had lovely fingernails. Since turning 70, my nails have become brittle, and they break easily. I am sure this is due to age, but is there anything I can do about it? – W.W.

ANSWER: If you polish your nails, go easy with polish remover. It’s better not to use it ever. Protect your nails from strong detergents by wearing gloves when you have to plunge your hands into soapy water. Get in the habit of wearing them anytime you have to get your hands wet.

Keep your nails short and clip them only after you have soaked them in warm water, when they are soft.

After washing your hands, apply to the nails a cream or ointment that contains lactic acid. Massaging the skin at the sides and bottoms of the nails is said to promote nail growth. And biotin, a B vitamin, might strengthen them.

For a few people, age is not the only reason for brittle nails. Iron deficiency and thyroid-gland problems can take their toll on nails. You don’t have to rush to your doctor, but bring the topic up at your next visit.

DEAR DR. DONOHUE: A number of months ago, you stated that there is no caffeine in chocolate. As I am trying to limit my caffeine intake because of episodic atrial fibrillation, that was good news for me.

I recently had another episode, and I had eaten chocolate a number of times since reading that bit on caffeine and chocolate. Perhaps you may want to alert your readers to the relationship between caffeine and chocolate. – N.S.

ANSWER: I wrote there was no caffeine in chocolate? That sent me scrambling through old columns to find such a statement. I can’t locate one. I’ve known there is caffeine in chocolate since about day 2 of my life.

One ounce (28 grams) of dark chocolate has between 10 mg and 20 mg of caffeine. That’s not a lot of caffeine, but it is still off-limits to those who are sensitive to it.

Some nice things can be said about chocolate. It contains flavonoids – antioxidants. They keep the body from rusting prematurely. They help prevent heart disease, stroke and artery hardening. Chocolate is not a wonder drug, but it’s something that usually can be enjoyed in moderation.

DEAR DR. DONOHUE: I have suffered from severe allergies and severe asthma since childhood. I take Advair, but it has had no noticeable effect on my nocturnal asthma, which is my main concern. Do you know any treatments that can ease nocturnal asthma? – D.R.

ANSWER: Asthma is recurrent episodes of breathlessness, wheezing, chest tightness and coughing due to a sudden narrowing of the airways. Asthma attacks often strike during the night, and the reasons why aren’t clear. Your first line of defense against night attacks is to allergy-proof the bedroom.

Frequent changing and washing of pillowcases, bed linen and sheets keeps the dust-mite population in the bedroom to tolerably low levels. Dust mites are often responsible for asthma attacks. If there is carpet in your bedroom, it might serve you in good stead to remove it, if the expense is not prohibitive – another way to reduce the mite population. The same goes for any stuffed furniture in the room.

Keep bedroom humidity well under 50 percent to discourage the growth of molds, another cause of asthma attacks.

Acid reflux is the spouting up of gastric acid into the esophagus, and it is the cause of heartburn. It can also bring on asthma attacks, and that can happen without having heartburn pain. Speak with your doctor about trying medicines that control reflux to see if it is playing a part in your attacks.

Your medicine, Advair, is a popular and effective asthma drug. It’s inhaled twice daily through the mouth. It has two ingredients, fluticasone and salmeterol. Fluticasone is a cortisone medicine that soothes irritated airways. Salmeterol dilates airways. If the drug is not working for you, it might be more beneficial to take medicines that are not in a fixed combination in one pill. The doses of each can be varied to better fit your needs. Furthermore, there are many other asthma drugs. A change would be worth a try. Singulair, Accolate and Zyflo are a few examples. You are not chained to only one medicine.

For more information on asthma, readers can order the asthma booklet by writing: Dr. Donohue – No. 602, Box 536475, Orlando, FL 32853-6475. Enclose a check or money order (no cash) for $4.50 U.S./$6.50 Can. with the recipient’s printed name and address. Please allow four weeks for delivery.

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.