What is oral submucous fibrosis?
Oral submucous fibrosis is a chronic, progressive, irreversible and yet avoidable collagen metabolic disorder of the mouth caused by chewing areca nut in betel quid or its variants. It resembles scleroderma but is localised to the mouth. There is an associated increased risk of developing squamous cell carcinoma of the mouth.
Who gets oral submucous fibrosis?
Oral submucous fibrosis is seen predominantly in Indians who chew betel quid or its variants such as gutkha (mitha pan), kiwam, zarda and pan masala. Sweetened versions of betel quid are sold to children as sweet supari, gua, mawa or mistee pan. The easy availability of packaged dried product such as gutkha, is increasing the incidence of this condition as it consists of a greater dry weight of areca nut than the traditional quid rolled in betel leaf (paan). In addition, the betel leaf may have some protective benefit.
Betel quid chewing is an addictive habit due to tobacco and areca nut in the quid. It gives a feeling of euphoria and well being. It is also used as an anti-helminthic agent (for intestinal worms) and to aid digestion after a meal.
The quid is chewed and often held in the mouth between the teeth and inside of the cheek, for minutes or hours. Some chewers swallow the quid; others spit it out.
Betel quid chewing is seen almost exclusively in the Indian subcontinent, South East Asia and western Pacific and wherever these populations have migrated. It has rarely been reported in non-Asians living in South East Asia or married to an Asian. The chemical composition of the areca nut varies between regions due to differences in cultivation and preparation. This will influence the frequency of oral submucous fibrosis in different populations.
Oral submucous fibrosis can be seen at any age except for young children. The predominant age group affected is 20-40 years. Compared to traditional betel quid, gutkha chewing tends to begin at a younger age and has a shorter time to the development of disease, so cases of oral submucous fibrosis have been seen as young as 11 years of age.
In some populations there was a female predominance, suggesting a possible hormonal influence or role for iron deficiency. More recently, with the ready availability of prepackaged commercial forms, a male predominance is now being reported.
The duration of betel quid chewing before the development of oral submucous fibrosis varies from a few months to many years, probably dependent on the composition of the quid and extent of the habit as well as genetic and other susceptibility factors.
Predisposing susceptibility factors such as genetic background may influence the development of oral submucous fibrosis with areca nut exposure. Rare families have been reported with this condition, yet have no betel quid chewing habit. An increased incidence of some specific tissue types have been identified.
The role of malnutrition is not clear, however it is seen most commonly in middle to lower socioeconomic classes in association with poor nutrition. Similarly the role of spices and chillis has also been questioned. Eating plenty of fruit and vegetables has been reported to be protective.
Clinical features of oral submucous fibrosis
The first symptom of oral submucous fibrosis is a burning sensation in the mouth especially when eating spicy food, sometimes also with small blister formation. The mouth may feel dry with ulcers.
On examination, even at an early stage, the oral mucosa looks white in a marble-like pattern, either diffusely throughout the mouth or in localised areas, or in a netlike pattern.
In later stages fibrosis develops:
- mouth cannot be opened as wide as normal, affecting eating and swallowing, speaking and dental hygiene.
- tongue becomes smooth, white and cannot move easily.
- The cheeks feel thick and firm and cannot ‘puff out’.
- lips become rubbery and thick with an elliptical shape.
In very severe cases, the fibrosis extends to the soft palate, throat and oesophagus. The uvula may shrink and become disorted in shape. Difficulty may occur with swallowing and the Eustacian tubes to the ear may be blocked, affecting hearing.
Although most of the inside of the mouth can become fibrotic, the gums are uncommonly affected. Involvement on just one side of the mouth has been reported when the betel quid is habitually held in one specific site. The pattern of involvement is also affected by whether the quid is swallowed after chewing, or spat out. Swallowing exposes the soft palate, throat and oesophagus to the betel quid and therefore these areas at the back of the mouth are more likely to be affected than in those who spit the quid out. Those who spit it out are more likely to have involvement of the lips and areas towards the front of the mouth.
There is an increased risk of developing squamous cell carcinoma in the thinned oral mucosa. The risk has been estimated to be as high as 1 in 5 in some reports.
How is oral submucous fibrosis diagnosed?
The diagnosis is usually made on history of areca nut exposure and clinical examination.
Suggested clinical criteria are one or more of the following:
- whitening of the oral mucosa
- palpable fibrous bands
- tough leathery texture to the oral mucosa
Mucosal biopsy shows nonspecific pathology in early stages with swelling and acute inflammation. However in well established disease, the pathology is characteristic with chronic inflammation and the presence of thick collagen bands and reduced blood vessels. The surface epithelium is thinned and dysplasia is common. Muscle degeneration is seen in late disease.
Barium swallow may be useful to assess throat and oesophageal involvement.
Blood tests may be required to assess nutritional state and for autoimmune conditions.
Treatment of oral submucous fibrosis
The betel quid chewing habit must cease to minimize disease progression, however there is usually no regression of the fibrosis. Frequent examination is required for the development of oral cancer. The extent of the mouth opening can be measured (average normal 40mm) and used to monitor disease progression or effect of treatment.
No treatment has been shown to be effective in reversing this condition.
The usual treatment is corticosteroid injections into the fibrotic bands every week for 6-8 weeks. Hyaluronidase, an enzyme to breakdown connective tissue, may be mixed with the cortisone. Mouth opening excercises are advised. Nutritional supplements may be added. There are reports of many treatments tried in this condition.
Surgery may be required for advanced disease to allow the mouth to open sufficiently for normal function.
Prevention is the best option as oral submcuous fibrosis rarely develops if areca nut is not chewed.