The Mouth and Lupus
IntroductionThe mouth can be affected by lupus erythematosus in a variety of ways but the most frequently occurring conditions are mucosal patches which are found in 10-25% of cases and xerostomia, which develops in up to 30% of sufferers. The mucosal lesions usually produce minimal symptoms whilst a lack of saliva causes a number of significant problems.
The possibility that intra-oral changes represent a lichenoid reaction rather than lupus itself must always be considered since such mucosal lesions are seen relatively frequently with the use of the nonsteroidal anti-inflammatory drugs that patients with lupus may be taking. If the onset of any oral symptoms coincides with the provision of systemic drug therapy then it may be necessary to consider an alternative medication.
Figure 1. White keratotic patch of lupus in the left buccal mucosa.
Xerostomia (Dry mouth)Saliva is produced by three pairs of major glands (parotid, submandibular and sublingual) and numerous minor glands scattered throughout the mouth. In health, the salivary glands produce approximately 0.75 litre of saliva in 24 hours. Almost a third of lupus patients suffer from a significant reduction in the production of saliva which causes oral symptoms (Table 1) and signs (Table 2). In addition to being dry, the oral mucosa becomes erythematous and the tongue may appear lobulated (Figure 2).
Difficulty in talking
Difficulty in swallowing
Loss of taste
Generalised oral discomfort
Difficulty with dentures
Discomfort at the angles of the mouth
Absence of saliva or frothy saliva
Dental caries, particularly at the cervical margins
Fracture and loss of dental restorations
Erythematous and pseudomembranous candidosis
Investigation of xerostomiaThe presence of a dry mouth can be crudely assessed by either simply looking in the patient's mouth to see if saliva is pooling behind the lower incisors or by placing the face of a dental mirror against the buccal mucosa (the mirror will stick to the mucosa if salivary levels are reduced).
In addition to these simple tests, a number of special investigations have been developed to detect reduced salivary production. Such special techniques include measurement of salivary flow rates, sialography, scintiscanning, serology and labial gland biopsy. The extent to which each of these tests is used will depend on an individual patient's history and the availability of the required facilities.
Salivary flow rates
The measurement of salivary flow rates is known as sialometry. Flow rates may be assessed either as "resting" or as stimulated. Collection of saliva from the parotid glands is achieved by the use of specifically designed collection devices (Carlsson-Crittenden cups) that are placed over the right and left parotid duct orifices. The cups are held in place by suction and salivary flow collected (resting flow). For the measurement of stimulated flow rates, salivary production is encouraged by placement of 1ml of 10% citric acid on the dorsum of the tongue. A flow of at least 0.7 mI/min over a period of five minutes would be considered normal, less than this value is indicative of reduced salivary function. Assessment of flow rates from the submandibular gland is more complicated and is usually only used for research purposes.
Sialography is a method of demonstrating the structure of the salivary duct network of either the submandibular or parotid gland. The technique is based on the infusion of a water-based radio-opaque contrast medium into the main excretory duct. The medium is usually introduced using a syringe and polythene cannula inserted into the excretory duct orifice. Radiographs, consisting of a lateral oblique and antero-posterior view, are taken whilst the patient feels the gland filling. Sialography is an invaluable method of demonstrating structural abnormalities within the salivary tissues. A "snow storm effect", known as sialectasis, is a characteristic finding in lupus due to pooling of the medium within the gland. Sialography is basically a safe and simple procedure, the only contra-indications being allergy to iodine or the presence of acute infection in the gland.
Radioisotopic study of salivary glands is based on the ability of active tissues to selectively uptake radioisotopes from the bloodstream. The isotope is introduced intravenously and the head/neck subsequently scanned by methods which are able to pick up isotopic emissions. This technique allows measurement of uptake and, therefore, provides an assessment of salivary gland function.
Immunological investigation of venous blood can be used to demonstrate the presence of specific autoantibodies associated with salivary gland disease including anti-Ro (SSA), anti-La (SSB) and anti-salivary duct antibody.
Labial gland biopsy
Sjögren's Syndrome comprises of dry mouth and/or dry eyes in combination with a connective tissue disorder, such as lupus. Histopathological examination of the minor salivary glands within the lower lip is the single most specific diagnostic test for confirmation of Sjögren's Syndrome and, therefore, can be used to confirm a diagnosis of lupus. The minor glands lie superficially behind the lower lip and can be collected simply under local anaesthesia by making a linear excision through the labial mucosa. At least five lobules of salivary tissue should be obtained since not all minor glands show the histopathological features of the condition.
Treatment of xerostomiaTreatment of dry mouth must not only involve attempts to replace the lack of saliva by the use of salivary substitutes or stimulants but should also include measures to minimise secondary problems, in particular dental caries (Figure 3).
Figure 3. Fracture of dental restorations and caries due to xerostomia.
A number of salivary substitutes, based on either methylcellulose or gastric mucin, are available in the British National Formulary (Table 3).
Artificial saliva BNF
Low pH, not suitable for dentate patients
Good pH, contains fluoride
Good pH, contains fluoride
Oral care systems have also been developed and include Biotène oral balance, BioXtra, Salinum, Saliveze, Salivix and SST. Details on these formulations are provided in the British National Formulary. In addition, Biotène have a range of products that may be used in improving oral hygiene in patients with xerostomia and Oramoist produce a mouth moistening lozenge and spray.
A number of methods of stimulating secretion of saliva have been suggested. Many sufferers of xerostomia resort to eating traditional boiled sweets in an attempt to relieve the dryness. However, it is important to tell such patients to stop this habit since the sugar intake will dramatically encourage dental caries. Saliva flow can be safely encouraged by the use of sugar-free chewing gum or diabetic sweets. Pilocarpine is a drug that has been recommended for the treatment of dry mouth following radiotherapy and has also been used in patients with lupus. Pilocarpine can be given in tablet form at a dose of 5mg two or three times a day. However, although pilocarpine does increase salivary flow it also results in excretion by other exocrine glands and patients complain of excessive sweating or tear production. Such unwanted side effects combined with a number of medical contraindications or other side effects limit the usefulness of pilocarpine. A glycerine and lemon based mouthwash can be effective in edentulous patients although it must not be given to sufferers who have natural teeth since the low pH will encourage dental caries.
Rigorous oral hygiene measures and preventive regimens, especially topical fluoride therapy, should be instituted as reduced amounts of saliva will predispose to an increased incidence of caries. In addition, it is essential that patients remove any dentures at night and clean them daily with soap using a small soft brush to dislodge food debris.
The use of a daily mouthwash containing sodium fluoride 0.05% will help reduce dental caries.
The patient should be asked to complete a diet diary over a four-day period (including a weekend). Subsequent dietary advice must concentrate on minimising cariogenic items, particularly sweetened drinks including tea and coffee.
Dry or cracked lips can be improved by use of a petroleum-based ointment such as vaseline. Patients who complain of thick or sticky saliva may gain some relief from the regular use of a mouthwash consisting of baking soda (1 teaspoon) and salt (1/2 teaspoon) in water (1 litre). Interestingly, symptoms of dry mouth have been anecdotally reported to respond to the provision of evening primrose oil at a dose of 1000mg daily. The use of drugs that are known to reduce salivary flow, in particular tricyclic antidepressants, such as dosulepin and amytriptyline, should be avoided in patients with dry mouth.
InfectionApproximately 40% of the adult population harbour candida in their mouths as part of the commensal oral flora. Reduced salivary flow can lead to an increase in the numbers of candida resulting in opportunistic oral candidoses. The clinical presentation may be either white pseudomembranes (thrush) or erythematous atrophic areas of mucosa. Candidal infections are particularly frequent if the patient wears dentures. Topical antifungal agents are of little or no benefit in the management of oral candidosis and, therefore, it is preferable to provide a seven-day course of systemic fluconazole (50mg daily). The need for denture hygiene should be stressed if there is evidence of candidal infection. Full dentures should be placed in a dilute solution of hypochlorite at night for approximately three weeks. Partial dentures with metal components should be placed in chlorhexidine.
Opportunistic bacterial infection may develop in the salivary glands, particularly the parotid glands, due to reduced flow of saliva down the excretory duct. Acute infection presents as a painful swelling of the affected gland accompanied by a discharge of pus at the main duct orifice. Oral amoxicillin is the antibiotic therapy of choice whilst erythromycin should be used in patients with a hypersensitivity to penicillins.
Prof Michael A O Lewis
Professor of Oral Medicine
School of Clinical Dentistry
Cardiff CF14 4XY