Symptoms of burning mouth syndrome may include: • A burning or scalding sensation that most commonly affects your tongue, but may also affect your lips, gums, palate, throat or whole mouth • A sensation of dry mouth with increased thirst • Taste changes in your mouth, such as a bitter or metallic taste • Loss of taste • Tingling, stinging or numbness in your mouth The discomfort from burning mouth syndrome typically has several different patterns. It may: • Occur every day, with little discomfort when you wake, but become worse as the day progresses • Start as soon as you wake up and last all day • Come and go Whatever pattern of mouth discomfort you have, burning mouth syndrome may last for months to years. In rare cases, symptoms may suddenly go away on their own or become less frequent. Some sensations may be temporarily relieved during eating or drinking. Burning mouth syndrome usually doesn't cause any noticeable physical changes to your tongue or mouth.

The cause of burning mouth syndrome can be classified as either primary or secondary.

Primary burning mouth syndrome

When no clinical or lab abnormalities can be identified, the condition is called primary or idiopathic burning mouth syndrome. Some research suggests that primary burning mouth syndrome is related to problems with taste and sensory nerves of the peripheral or central nervous system.

Secondary burning mouth syndrome

Sometimes burning mouth syndrome is caused by an underlying medical condition. In these cases, it's called secondary burning mouth syndrome.

Underlying problems that may be linked to secondary burning mouth syndrome include:

• Dry mouth (xerostomia), which can be caused by various medications, health problems, problems with salivary gland function or the side effects of cancer treatment
• Other oral conditions, such as a fungal infection of the mouth (oral thrush), an inflammatory condition called oral lichen planus or a condition called geographic tongue that gives the tongue a maplike appearance
• Nutritional deficiencies, such as a lack of iron, zinc, folate (vitamin B-9), thiamin (vitamin B-1), riboflavin (vitamin B-2), pyridoxine (vitamin B-6) and cobalamin (vitamin B-12)
• Allergies or reactions to foods, food flavorings, other food additives, fragrances, dyes or dental-work substances
• Reflux of stomach acid (gastroesophageal reflux disease, or GERD) that enters your mouth from your stomach
• Certain medications, particularly high blood pressure medications
• Oral habits, such as tongue thrusting, biting the tip of the tongue and teeth grinding (bruxism)
• Endocrine disorders, such as diabetes or underactive thyroid (hypothyroidism)
• Excessive mouth irritation, which may result from overbrushing your tongue, using abrasive toothpastes, overusing mouthwashes or having too many acidic drinks
• Psychological factors, such as anxiety, depression or stress

Wearing dentures, even if they don't fit well and cause irritation, doesn't generally cause burning mouth syndrome, but dentures can make symptoms worse.

Burning mouth syndrome is uncommon. However, your risk may be greater if:

• You're a woman
• You're perimenopausal or postmenopausal
• You're over the age of 50

Burning mouth syndrome usually begins spontaneously, with no known triggering factor. However, certain factors may increase your risk of developing burning mouth syndrome, including:

• Recent illness
• Some chronic medical disorders such as fibromyalgia, Parkinson's disease, autoimmune disorders and neuropathy
• Previous dental procedures
• Allergic reactions to food
• Medications
• Traumatic life events
• Stress
• Anxiety
• Depression

Complications that burning mouth syndrome may cause or be associated with are mainly related to discomfort. They include, for example:

• Difficulty falling asleep
• Difficulty eating
• Depression
• Anxiety