Plasma Cell Gingivitis

Plasma cell gingivitis is a diffuse, sharply demarcated, erythematous and oedematous gingivitis caused by a hypersensitivity reaction, in which the gingival connective tissue is infiltrated by mature plasma cells. It is also called allergic gingivostomatitis.

The attached gingiva is usually involved, the upper labial gingiva most often, and the lips and tongue can be affected at the same time. It is uncommon and seen in all ages, with women somewhat more affected.

Pathophysiology. An allergic reaction to a flavouring or additive, classically cinnamon in toothpaste, chewing gum, sweets or herbal products, produces polyclonal plasma cell infiltration and oedema of the lamina propria.

The condition can also follow other allergens such as mint, nuts and some dental materials, and in some patients no trigger is found.

Bright red, swollen, velvety or granular gingiva with a clear limit at the mucogingival junction, sometimes with bleeding, burning and soreness, and minimal plaque. The lips may show cheilitis, with angular fissures, and the tongue may be red and smooth.

Ask about toothpaste, chewing gum, mouthwash, sweets, spices and herbal remedies, and about a recent change in products. Onset can follow weeks of exposure.

• Clinical diagnosis with allergen history, supported by biopsy: dense sheets of mature plasma cells in the lamina propria with oedema and inflammation.
• Immunohistochemistry for kappa and lambda light chains to show a polyclonal infiltrate. A monoclonal pattern needs a haematology workup.
• Serum protein electrophoresis, free light chains, calcium, creatinine and full blood count when plasma cells are atypical or extramedullary plasmacytoma is a concern.
• Patch testing to flavours and a dental series.
• HIV test and swab for Candida when the history or appearance suggests them.

Differential diagnosis.

• Plaque induced gingivitis
• Desquamative gingivitis from lichen planus or pemphigoid
• Orofacial granulomatosis
• Gingival plasmacytoma or myeloma
• Candidal gingivitis
• Drug induced gingival enlargement
• Leukaemic infiltration of gingiva

• Identify and withdraw the allergen. Stop cinnamon containing and strongly flavoured toothpaste and gum, and use a plain, low flavour fluoride toothpaste. Improvement usually begins within 2 to 4 weeks.
• Professional plaque and calculus removal with meticulous oral hygiene instruction.
• If still symptomatic after 2 to 4 weeks, topical corticosteroid: clobetasol propionate 0.05% gel in a custom tray or applied with a finger 2 to 3 times daily for 2 to 4 weeks, then reduced. Consider miconazole oral gel 20 mg/g, 2.5 mL four times daily for 7 days if candidiasis develops, avoiding it with warfarin.
• Chlorhexidine 0.2% mouthwash 10 mL for 1 minute twice daily for up to 2 weeks as an adjunct for plaque control, accepting tooth staining.
• Short systemic steroid courses are rarely needed. Immunosuppressive therapy is reserved for unusual, refractory cases.
• Biopsy confirmed monoclonal disease needs haematology and oncology care.

Monitoring. Review at 4 weeks and 3 months to confirm resolution, then at routine dental recall. Recurrence points to re-exposure.

Referral and escalation. Refer to oral medicine if there is no response in 4 to 6 weeks. Refer urgently to haematology for monoclonal plasma cells, hypercalcaemia, paraprotein or lymphadenopathy.