What is oral dysaesthesia?

Oral dysaesthesia describes a painful, burning feeling in the mouth. See Cutaneous dysaesthesia. It can be classified as:

• ‘Primary’ when no organic cause can be identified. This form is usually called ‘burning mouth syndrome’ although there are numerous other names used including orodynia and glossodynia
• ‘Secondary’ when a local or systemic cause can be found for the symptom.

Causes of secondary oral dysaesthesia

Oral dysaesthesia may result from local or systemic conditions.

What are the clinical features of oral dysaesthesia?

When taking the history, the pattern of pain can be classified into three types:

• Type 1 – pain absent on waking, gradually increasing during the day
• Type 2 – pain can be present throughout the day and night
• Type 3 – intermittent with pain-free days.

Further questioning will inquire about symptoms of associated disorders, general health, diet and medication use including prescribed, over-the-counter and alternative therapies.

A thorough clinical examination must be performed. This should include careful evaluation of the mouth, head and neck for local causes. A general examination including the skin and nails may provide evidence of nutritional deficiencies, autoimmune and connective tissue diseases, hormonal deficiencies or lichen planus. A neurological examination will assess for neurological deficits including the neuropathies of diabetes and vitamin B12 deficiency.

How is the diagnosis of oral dysaesthesia made?

The diagnosis of oral dysaesthesia is made on careful history and examination. Sometimes the pattern of pain may give a clue as to the cause:

• Type 1 – nutritional deficiency, diabetes
• Type 2 – chronic anxiety
• Type 3 – food allergy

A list of possible causes can then be made.

The actual cause, however, may only be determined with further investigations. These will be determined by the clinical findings and may include:

Blood tests

• Full blood examination
• ESR
• Fasting blood sugar
• Serum folate and vitamin B12 levels
• Iron studies
• FSH/LH
• Thyroid hormone studies
• Autoantibodies – antithyroperoxidase, antimicrosomal, antithyroglobulin
• ANA, RF, anti-SS, -Ro, -SS-B, -SS-La antibodies

Other tests

• Imaging studies may include computed tomography (CT) scan (head), magnetic resonance imaging (MRI) (head, spinal cord), and thyroid scan
• Lumbar puncture
• Mucosal biopsy for histopathology and possibly immunofluorescence
• Mucosal scraping or swabs for microbiological assessment
• Patch tests with benzoic acid, benzoyl peroxide, chestnuts, cinnamate, cobalt chloride, mercury, acrylate, nicotinic acid, octyl gallate, peanuts, petrolatum, cadmium sulfate, propylene glycol, sorbic acid
• Schirmer test
• Sialometry
• Upper gastrointestinal tract endoscopy

What is the treatment of oral dysaesthesia?

Treatment is of the underlying condition, and therefore options will include, amongst others:

• Ceasing/changing drugs that cause xerostomia or oral pain
• Oral nystatin
• Adjust the dose of thyroxine
• Avoid potential contact irritants and allergens
• Cease smoking or oral tobacco use
• Chew sorbitol-containing gum to stimulate saliva
• Supplements of folate, iron and B group vitamins
• Dental care such as adjust dental prostheses.