Topics in Periodontology

Necrotising Ulcerative Gingivitis

From the DentTest dentistry textbook. Last updated 6 August 2026.

Clinical case

A 21-year-old university student presents with sudden-onset severe gingival pain, spontaneous bleeding when brushing, halitosis, and difficulty eating. He reports recent examination stress, poor sleep, smoking, and reduced oral hygiene. On examination, the interdental papillae are “punched out,” ulcerated, and covered by a grey-yellow pseudomembrane. The lesions bleed readily on gentle probing, but there is no clear evidence of attachment loss or alveolar bone loss

Pathophysiology

Necrotising ulcerative gingivitis (NUG) is thought to arise from an opportunistic polymicrobial infection of the gingiva in a susceptible host.

  • Anaerobic organisms and spirochaetes are strongly implicated, with organisms such as Treponema, Fusobacterium, and other anaerobic species commonly associated.

  • The disease is not simply due to plaque quantity alone; rather, it reflects a breakdown in host defence combined with local plaque accumulation and systemic or behavioural stressors.

  • Tissue necrosis produces the characteristic ulcerated papillae and fibrinous pseudomembrane.

Epidemiology and Risk Factors

NUG is now uncommon in high-income settings, with reported prevalence generally below 1%, though it remains clinically important because of its rapid onset and potential progression. It is seen more often in young adults under stress, smokers, patients with poor oral hygiene, and immunocompromised individuals.

Non-modifiable

Modifiable

Immunocompromised patients, for example:

  • Autoimmune disease

  • Cancer

Smoking

Diabetes mellitus

HIV

Poor plaque control

Psychological stress

Sleep deprivation

Clinical Features

Symptoms

Signs

Severe gingival pain

"Punched-out" necrosis of interdental papillae

Spontaneous or provoked gingival bleeding

Inflamed marginal gingiva

Halitosis

Grey or yellow pseudomembrane over necrotic areas

Bad or metallic taste

Tenderness on gentle probing

Difficulty eating or brushing

Spontaneous or easy bleeding on manipulation

Fever is possible but uncommon

Investigations

Primary investigations:

  • Clinical examination including periodontal examination with gentle probing

  • Assessment of oral hygiene and plaque retentive factors

  • Review of risk factors

Gold standard investigation:

  • There is no laboratory gold standard investigation for NUG, the diagnosis is primarily clinical

Investigations to consider:

  • Periapical or bitewing radiographs

  • Full periodontal charting once acute pain settles

  • Blood tests and further medical assessment if the disease is severe, recurrent or atypical, suggesting potential underlying immunosuppression

Differential diagnosis

  • Primary herpetic gingivostomatitis

  • Desquamative gingivitis

  • Streptococcal or gonococcal gingivitis

  • Erythema multiform

  • Pemphigus vulgaris

  • Acute leukaemia

Management

Acute Treatment (Day 1-3) 

  • Gentle Debridement: Remove loose necrotic tissue and supragingival plaque using ultrasonic instruments (often requires local anaesthesia). Avoid aggressive probing or subgingival scaling initially.

  • Antimicrobial Rinses: Advise rinsing twice daily with 0.12%-0.2% Chlorhexidine gluconate or 1.5%-3% Hydrogen peroxide (diluted 1:1 with warm water) to reduce bacterial load.

  • Systemic Antibiotics: Prescribe only if systemic involvement (fever, malaise, lymphadenopathy) or severe immunodeficiency is present.

    • First Choice: Metronidazole 400mg-500mg, 3 times a day for 3–5 days.

    • Alternative: Amoxicillin 500mg, 3 times a day for 3 days.

  • Pain Relief & Supportive Care: Recommend analgesics (NSAIDs like Ibuprofen or Paracetamol). Recommend rest, high fluid intake, and avoiding tobacco, alcohol, and spicy foods.

  • Oral Hygiene Instruction (OHI): Advise gentle brushing with a soft toothbrush. 

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