Burning mouth syndrome: intense burning on a mucosa that looks entirely normal

A persistent burning of the tongue and oral mucosa, with no objective sign whatsoever. The mismatch between the intensity of the symptom and the normality of the appearance is the defining feature.

The sites most affected are the tip and lateral borders of the tongue, the palate and the lips, typically in a bilateral and symmetrical distribution.

The daily pattern is characteristic and should be asked about explicitly: the symptom is absent or mild on waking, increases through the day and peaks in the evening. Many patients report relief while eating, which is counterintuitive and useful in orientation.

Frequently associated are an altered sense of taste, described as a persistent metallic or bitter flavour, and a sensation of dry mouth that does not correspond to any objective reduction in salivary flow.

The condition is more frequent in women, with a marked increase after menopause.

The fundamental distinction is between the secondary form, where an identifiable and treatable cause exists, and the primary form, which is a diagnosis of exclusion and corresponds to neuropathic pain.

The list of what must be excluded is the concrete part of the work. Candidiasis comes first, and should be looked for even without obvious plaques, because the erythematous form presents only as a diffuse redness that is easily overlooked.

Then come nutritional deficiencies: iron, folate, vitamin B12 and zinc, documented through blood tests rather than inspection.

Also to be considered are uncontrolled diabetes, drug-induced xerostomia, gastro-oesophageal reflux, reactions to prosthetic materials, and tongue parafunction against the arches. Among drugs associated with the symptom, ACE inhibitors are the most frequently cited.

The path these patients travel before reaching a diagnosis is almost always long: many consultations, many negative tests, and a growing sense of not being believed.

This is why the most damaging thing to say is that there is nothing wrong. The absence of visible signs does not equal the absence of disease, and in the primary form what is being described is real neuropathic pain.

The hygienist's role is well defined: exclude what falls within their competence, refer for blood tests and medical assessment, and act on the factors that aggravate the symptom, namely toothpastes containing sodium lauryl sulfate, alcohol-based mouthwashes, and acidic or spicy foods. Without promising a rapid resolution, which in the primary form generally does not come.

In summary: the symptom is intense while the mucosa looks normal, burning worsens through the day and often improves while eating, the secondary form has an identifiable cause while the primary is a diagnosis of exclusion, erythematous candidiasis and nutritional deficiencies must be excluded first, and telling the patient there is nothing wrong is the most damaging error.