Lichen planus

What is oral lichen planus (OLP)?

Oral lichen planus (OLP) is a relatively common condition that can affect around 1-2% of the population with a predilection for middle aged female patients. It is a benign condition that affects the oral mucosa, as well as also affecting other mucosal surfaces such as the genitalia, anus and pharynx. It can also be combined with skin lesions.

What is/are the causes(s) of lichen planus?

The underlying cause of OLP remains unclear. It is thought to be a cell-mediated immunological reaction in response to an unknown trigger, as a characteristic hallmark on tissue analysis is a white cell infiltrate in the sub-epithelial layer.

Some patients may have lichenoid lesions rather than OLP. These can be precipitated by local or systemic factors including lichenoid drug reaction (e.g. angiotensin-converting enzyme (ACE) inhibitors), certain dental restorative materials (e.g. gold) and a rare condition called graft versus host disease (GvHD).

Finally, lichen planus-like issues can present in autoimmune liver disease (e.g. primary biliary cirrhosis) and chronic active hepatitis, particularly hepatitis C infection.

What are the symptoms of lichen planus?

OLP is characteristically bilateral and widespread over the oral mucosa, affecting potentially all the mucosa surfaces but most commonly the inside of the cheeks. It is often asymptomatic but may cause pain and discomfort, exacerbated by eating spicy or acidic foods.

Patients can present with a variety of mucosal lesions including erosive areas, white patches, ulcers and blisters. These subclassify OLP depending on the appearance, including (but not limited to) the following:

• reticular;
• plaque-like;
• atrophic;
• ulcerative;
• bullous.

Patients can also present with a full width inflammation of the gums (gingivitis) which is unrelated to oral hygiene and periodontal disease, called desquamative gingivitis.

Not uncommonly, asymptomatic patients can be referred in by their dentists, as there is an incidental finding of a white patch and a need to exclude other causes of white patches such as oral cancer.

What investigations will be done?

The first priority is a thorough clinical examination. This is done under direct vision and will also encompass an examination of the neck lymph nodes and major salivary glands by palpation. This will also look for precipitants, such as certain restorations. A thorough medical history will be taken to identify any particular medications that might be responsible. This will also focus on excluding potential underlying causes, such as autoimmune liver disease, hepatitis C and GvHD.

In some instances, a flexible nasendoscopy (FNE) will be warranted, passing a small camera through the nose to examine the upper aerodigestive tract (nasopharynx, oropharynx and laryngopharynx).

One of the mainstays of diagnosis is a biopsy. This involves a minor procedure done in the outpatient setting. A small amount of local anaesthetic will be injected into an affected area of the gums (commonly the inside of the cheek) and a tissue sample taken (around 4-5mm in diameter) with some dissolving sutures placed. This is quick, generally taking around 10 minutes, and is relatively painless besides the initial injections.

What treatments are available?

Many patients with OLP do not require any specific treatment as they have no symptoms. In this instance, it is still important to attend for regular dental and/or specialist reviews to monitor the condition.

Patients can benefit from intermittent use of anaesthetics to reduce symptoms e.g. Difflam® (benzydamine hydrochloride) spray/mouthwash and topical lidocaine gel.

For patients with mild symptoms, topical steroids are usually the mainstay of treatment. This can be in the form of mouthwashes and/or ointments/pastes that are applied to the affected areas. Common steroids prescribed including:

• prednisolone dispersible tablets dissolved in water and used as a mouthrinse;
• betamethasone 500mcg tablets;
• fluticasone propionate spray (previously Flixonase® Nasule drops);
• clobetasol 0.05% ointment.

It should be noted that these are used as mouthrinses for their topical effect and not to be swallowed unless instructed otherwise.

Removal of any identified precipitants may be undertaken e.g. replacing certain fillings/restorations (gold crowns, etc.) and/or substituting drugs in conjunction with the General Practitioner (GP) (e.g. ACE-I switched for alternatives).

Sometimes antifungal drugs may be required to treat any associated superinfection on the friable mucosa.

For patients who fail to respond to the above measures and/or whose symptoms are particularly severe, systemic steroids may be prescribed. These are given under close specialist supervision as risks may include diabetes, weight gain and loss of bone density among others.

Less commonly, additional drugs may be required such as steroid-sparing agents and immunosuppressants (e.g. azathioprine, ciclosporin, tacrolimus). Again, these drugs have a number of side effects and potential risks, their use is not undertaken lightly and close monitoring is required.

What can I do to manage my condition?

Keeping a food diary can be helpful, to identify anything that makes symptoms worse enabling you to avoid or limit particular items, provided this does not interfere with adequate oral intake and nutrition. Avoiding/limiting alcohol intake can be beneficial and stopping smoking is paramount.

It is important that you maintain a good standard of oral hygiene and ensure that mucosal trauma is kept to a minimum (e.g. attending early when dentures become ill-fitting for replacement/adjustment).

It is also very important that you attend for regular reviews and present early with any significant changes in symptoms and/or character of any oral lesions. It is recognised that oral lichen planus has the potential for malignant transformation (i.e. becoming cancerous), albeit small at around 1-2%. This risk may be magnified by the presence of a feature called epithelial dysplasia on biopsy, consumption of tobacco and/or alcohol, atrophic or erosive patterns and/or infection by the hepatitis C virus.

For the vast majority of patients, OLP is a benign and harmless condition that is more of a nuisance than anything of any great concern. Rather like eczema, it is often a condition you “live with” and control, rather than cure.