There are a few mouth conditions so rare most of us have never heard of them. Geographic tongue would fall into this category, affecting only one to three percent of the population. Even so, these irregular reddish patches resembling land masses on a map (hence the name) might be alarming at first glance—but they pose no danger and usually cause very little discomfort.

Geographic tongue is also known as benign migratory glossitis. As its clinical name implies, the unusual red patchy areas (often surrounded by a grayish white border) aren't cancerous nor contagious. The patches also appear to change shape and move around ("migrate") the tongue.

The reddish appearance comes from the temporary disappearance of tiny bumps on the tongue surface called papillae, which can leave the tongue smooth to the touch in affected areas. The lost papillae may reappear again a few hours or days later, and may occasionally disappear again. While it's not painful, you can experience a stinging or burning sensation emitting from these patchy areas.

We're not sure how and why geographic tongue erupts, but it's believed high emotional or psychological stress, hormonal imbalance or certain vitamin deficiencies might be factors in its cause. There may also be a link between it and psoriasis, a condition that can cause dry, itchy patches on the skin.

If you're one of the rare individuals who has episodes of geographic tongue, the good news is it's harmless, only mildly uncomfortable and usually temporary. The bad news, though, is that there's no known cure for the condition—but it can be managed to ease discomfort during outbreaks.

It's been found that highly acidic and spicy foods, as well as astringents like alcohol or some mouthrinses, can increase the level of discomfort. By avoiding these or similar foods or substances, you can reduce the irritation. Your dentist may also be able to help by prescribing anesthetic mouthrinses, antihistamines or steroid ointments.

For the most part, you'll simply have to wait it out. Other than the mild, physical discomfort, the worst part is often simply the appearance of the tongue. But by watching your diet and other habits, and with a little help from us, you can cope with these irritations when it occurs.