Oral Submucous Fibrosis

Oral submucous fibrosis (OSMF) is a chronic, progressive, potentially malignant disorder characterised by juxtaepithelial inflammation and fibrosis of the oral submucosa, leading to stiffness and trismus. The principal cause is chewing areca (betel) nut, with or without tobacco or slaked lime (quid, paan, gutka), with the dose response related to frequency and duration. It is common in South Asia and among South Asian migrant communities in East Africa, and prevalence is rising with commercial areca preparations.

Mechanism: areca alkaloids (arecoline) stimulate fibroblast collagen production, inhibit collagen degradation, and increase lysyl oxidase and TGF-beta; copper in areca nut contributes. Collagen deposition is replaced by dense fibrous bands, atrophic epithelium, and reduced vascularity. Malignant transformation to oral squamous cell carcinoma is 7 to 13 percent over 10 to 17 years, the risk being highest in advanced disease.

The condition is irreversible but can be controlled by stopping areca use. Staging is based on mouth opening: stage 1 (over 35 mm), stage 2 (25 to 35 mm), stage 3 (15 to 25 mm), stage 4 (under 15 mm).

• Burning sensation, intolerance to spicy food, pallor of mucosa, vesicles, ulcers, xerostomia, loss of taste.
• Progressive trismus, difficulty eating and speaking, inability to open the mouth fully, difficulty protruding the tongue.
• Blanched, marble like mucosa; palpable vertical fibrous bands in the buccal mucosa, soft palate, faucial pillars; shrunken uvula ("bud like"); stiff, depapillated tongue.
• Leukoplakia or erythroplakia may coexist; nasal voice; hearing loss from Eustachian tube involvement.
• Red flags: ulcer, indurated nodule, red or speckled patch, non-healing lesion beyond 3 weeks, cervical lymphadenopathy, rapid weight loss.

• Clinical diagnosis based on blanching, palpable fibrous bands, and restricted mouth opening in a person with areca nut use.
• Measure interincisal opening (normal 40 to 55 mm) and cheek flexibility; tongue protrusion.
• Biopsy of suspicious areas: subepithelial fibrosis with hyalinisation of collagen, epithelial atrophy or hyperplasia with dysplasia, reduced vascularity, chronic inflammatory cells.
• Toluidine blue staining or autofluorescence to select biopsy sites.
• Imaging (ultrasonography, MRI) can measure submucosal thickness.
• Full blood count and iron studies (anaemia is common), HIV test if indicated.
• Exclude trismus from infection or tetanus, scleroderma, TMJ ankylosis, oral lichen planus, burn scarring, post-radiation fibrosis, and malignancy.

• Stop areca nut, tobacco and alcohol; this is the cornerstone and halts progression; offer cessation support (behavioural counselling, nicotine replacement for smokers: patch 21 mg per 24 hours for 6 weeks, then 14 mg for 2 weeks, then 7 mg for 2 weeks).
• Mouth opening exercises: passive stretching using a wooden spatula stack, Heister mouth gag or a mechanical jaw exerciser, 10 repetitions for 5 minutes, 5 to 6 times a day, for at least 6 months.
• Stage 1 to 2 medical therapy: lycopene 8 mg orally twice daily for 3 months; antioxidant capsule; pentoxifylline 400 mg orally three times daily for 6 months with food (monitor for gastrointestinal upset); oral iron and multivitamins (vitamin A 5000 IU, vitamin E 400 IU) for 3 months.
• Intralesional injections: hyaluronidase 1500 IU with dexamethasone 4 mg in 1 mL lidocaine, injected into each affected buccal band (0.5 to 1 mL per site) weekly for 8 to 12 weeks; or triamcinolone acetonide 10 mg/mL, 0.5 mL per site, every 2 weeks for 4 to 6 doses (risk of atrophy, candidiasis).
• Topical: dexamethasone 0.1 percent in oral paste three times daily for burning; benzydamine 0.15 percent rinse for pain.
• Surgery for stage 3 to 4 with mouth opening under 20 mm: excision of fibrous bands with split thickness skin graft, buccal fat pad, nasolabial flap or radial forearm free flap, followed by early intensive jaw physiotherapy for 6 months; coronoidectomy when needed; reconstruction in the severe disease.
• Analgesia: paracetamol 1 g every 6 hours.
• Cancer surveillance: examination every 3 months for the first year, then every 6 months for life; biopsy any change; photographs.
• Counselling: stopping areca prevents progression, but fibrosis and cancer risk persist for years; education about areca products in the community.