Case• 34. A sore mouth
A 55-year-old gentleman presents to you in general practice complaining of a sore mouth. You must make a diagnosis and institute treatment.
He complains of an extremely sore mouth and the recent appearance of white patches on his cheeks. He thinks he may be allergic to his dentures.
History of complaint
The patient was fitted with a new set of complete dentures 3 weeks ago and since then his mouth has become progressively more sore. In recent days he has noticed the appearance of white patches on his cheeks. He had not noticed these before.
One year ago the patient was diagnosed as a non-insulin-dependent diabetic and he has a history of peptic ulceration. Current medications are metformin and ranitidine. He is otherwise fit and well.
The patient appears fit and well. No cervical lymph nodes are palpable.
The patient is edentulous and his complete dentures are stable and retentive. The appearance of the right and left buccal mucosa is shown in Figure 34.1. Despite its abnormal appearance the mucosa is freely mobile with no evidence of tethering or scarring. Other parts of the oral mucosa appear healthy and the mouth is well lubricated by saliva.
▪ Describe what you see on the buccal mucosa.
The buccal mucosa is affected bilaterally by poorly defined ulcerated red and white lesions. These extend from the commissural region to the retromolar area, as well as vertically into the upper and lower buccal sulci. The white areas are arranged as diffuse zones but some have reticular keratotic striae within them and around their borders. Irregularly shaped erythematous zones lie around the white areas and some have ulcers centrally. There are two large oval/linear ulcers approximately a centimetre in length on the left and one smaller ulcer on the right. The ulcers have yellow fibrinous sloughs on their surfaces and appear relatively superficial and flat rather than deep or punched out. No bleeding is evident.
▪ Suggest a differential diagnosis.
1. Lichen planus
2. Lichenoid drug reaction
3. Lupus erythematosus.
▪ Justify this differential diagnosis.
The combination of white, red and ulcerated areas alone is highly suggestive of one of these three conditions, though it could also be seen in a number of other mucosal diseases including vesiculobullous diseases. However, the presence of white striae as well is almost conclusive evidence that the patient is suffering from one of this group of lichen planus-like conditions. The lesions cannot be differentiated by their clinical appearance alone.
Lichen planus. From the clinical appearance alone, lichen planus seems the most likely diagnosis. Lichen planus is a chronic condition that predominantly affects middle-aged or elderly patients and is the commonest of the three possible diagnoses. The appearances are typical of the atrophic (‘erosive’) form of the disease in which there are keratotic white areas associated with erythema and shallow ulceration. If this were lichen planus it would be slightly unusual. The lesions are usually less extensive and more prominent on the posterior buccal mucosa. Nevertheless, this could be a more severely affected individual.
Lichenoid drug reaction. Lichenoid drug reactions are side-effects of a number of drugs including the oral hypoglycaemic drug taken by the patient. Lichenoid reactions may be local (e.g. in response restorations) or systemic, in which case they are usually caused by medication. Some features which point to a lichenoid drug reaction rather than lichen planus include acute onset, extensive ulceration, asymmetrical distribution and severe involvement of the dorsum of the tongue. Lesions may also affect sites such as the floor of mouth which are less commonly affected by lichen planus. Lichenoid reactions may be clinically indistinguishable from lichen planus and the appearances of the buccal mucosa are consistent with a lichenoid reaction.
Lupus erythematosus. The mouth may be involved in discoid and systemic lupus erythematosus (SLE) and the oral manifestations of both types are indistinguishable. The clinical features resemble those of lichen planus and lichenoid reactions but some features may help in diagnosis. Lesions in lupus erythematosus often have a central ulcer or erythematous area around which the striae tend to radiate rather than follow the random pattern of lichen planus. Lesions are also typically asymmetrical and affect the hard and soft palate, which are rarely involved by lichen planus or lichenoid reactions. Lupus erythematosus is much rarer than either of the other two possibilities and is unlikely as a new finding in a 55-year-old male.
▪ What further questions and examinations are appropriate? Explain why.
See Table 34.1.
|Subject||Questions and reasons|
|About the medication||
Date started, dose and any recent dose changes. Previous drug history for the last 5 years. Lichenoid reactions are sometimes dose dependent and may be first noticed as a result of an increase in dosage.
A close temporal relationship between starting a drug and developing lesions is good, though circumstantial, evidence of a causal link. Sometimes lichenoid reactions persist for years after the drug was administered.
|About skin lesions||
Are skin lesions present? Ask about and examine the flexor surface of the wrist and extensor surface of the shins. These are common sites for skin lesions of lichen planus and lichenoid reactions. The typical skin lesions are purplish polygonal papules with faint striae (Wickham’s striae). They are usually very itchy. Severe lichenoid reactions may be accompanied by an extensive erythematous rash.