Pain and paresthesias in the tongue (glossalgia)

Complaints of pain and paresthesia in the tongue (itching, numbness, soreness, distension, burning, etc.) are often encountered among patients with neurological and somatic profiles. Neurological examination rarely reveals conclusive sensory (and motor) disorders. It is useful to pay attention to the unilateral or bilateral nature of paresthesia and to diseases of the gastrointestinal tract.

I. Unilateral (damage to the lingual nerve):

1. Iatrogenic damage;
2. Limited neoplastic or inflammatory process of the posterior lateral region of the oral cavity;

II. Bilateral:

1. Psychogenic pain;
2. Carcinoma of the upper larynx and related conditions;
3. Pernicious anemia.

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I. Unilateral pain in the tongue (damage to the lingual nerve)

Sensory disturbances in one half of the tongue indicate damage to the lingual nerve, which is one of the largest branches of the mandibular nerve, the third branch of the trigeminal nerve. The lingual nerve innervates the anterior two-thirds of the tongue, but it is always necessary to check the sensitivity of the posterior third of the tongue, innervated by the glossopharyngeal nerve.

The pain usually does not have the characteristics of trigeminal neuralgia, but is more prolonged and less intense. As a rule, movement or sensory stimulation are not triggers. Often the pain is of a burning nature. Some patients experience a decrease in taste sensations. Sensations on the other half of the tongue and on the oral mucosa are preserved.

It is important to establish that the sensory disturbances are limited to the tongue only and do not extend to the area innervated by the inferior alveolar nerve. This area includes the mandibular teeth and the mucous membrane of the lower oral cavity. In this case, the site of damage should be sought laterally in the oral cavity, near the angle of the mandible.

Iatrogenic damage

The most common cause of iatrogenic injury is the extraction of the second and especially the third molar. Sometimes the nerve is damaged by osteotomy or similar surgical procedures, or by incision of a sublingual abscess.

Limited neoplastic or inflammatory process of the posterior lateral region of the oral cavity

The inflammatory process can damage the nerve due to compression or toxic damage, the nerve can also be damaged by a tumor.

II. Bilateral pain in the tongue

Psychogenic pain

In case of bilateral numbness or burning pain in the tongue without taste disturbance, the most common diagnosis is psychogenic pain. It is difficult to imagine a pathological process with symmetrical localization in the oral cavity, closely associated with the angle of the lower jaw, to explain the anatomical cause of this pain, and when such a pathological process does occur, a decrease in taste sensations is the leading clinical picture. Patients with psychogenic disorders often do not have a decrease in mood. On the contrary, they can demonstrate emotional activity and deny emotional problems. A decrease or complete disappearance of symptoms during meals is characteristic.

A tendency towards anxiety-hypochondriacal disorders is often revealed against the background of one or another dysfunction of the gastrointestinal tract.

The suspected diagnosis is confirmed by relief of symptoms due to the use of antidepressants, neuroleptics and treatment with psychotherapy.

Carcinoma of the upper larynx and related conditions

However, one should not rely too much on this effect of drugs, since even sensitive symptoms of organic origin can be reduced under their influence. Thus, it is advisable to fully examine such patients with visualization of the upper part of the larynx, the base of the skull, since some patients may develop symptoms of damage to the mandibular branch of the trigeminal nerve, which were not detected during the previous examination.

Pernicious anemia

In rare cases, burning pain in the tongue may be the leading symptom of pernicious anemia. The fact that this condition is becoming more or less rare may be due to the widespread parenteral administration of preparations containing more than the daily requirement of vitamin B12. These preparations are mistakenly prescribed for pain of various origins. And thus, the underlying vitamin B12 deficiency is inadvertently treated.

Diagnosis is based on serologic tests, including serum vitamin B12 levels, gastrointestinal absorption, and microscopic examination of bone marrow. The appearance of the tongue is often altered ("scalded tongue," "varnished tongue").