What are the clinical features and management of acute necrotizing ulcerative gingivitis (ANUG)?

Medical Advisory BoardAll articles are reviewed for accuracy by our Medical Advisory Board
Educational purpose only • Exercise caution as content is pending human review
Article Review Status
Submitted
Under Review
Approved

Last updated: January 12, 2026View editorial policy

Personalize

Help us tailor your experience

Which best describes you? Your choice helps us use language that's most understandable for you.

Acute Necrotizing Ulcerative Gingivitis: Clinical Features and Management

Clinical Features

Acute necrotizing ulcerative gingivitis (ANUG) presents with three pathognomonic features: painful gingival ulceration, spontaneous gingival bleeding, and characteristic necrosis of the interdental papillae. 1, 2

Primary Clinical Characteristics

  • Interdental papillae necrosis with characteristic "punched-out" appearance is the most diagnostic feature 1, 2
  • Severe gingival pain that is disproportionate to clinical appearance 1
  • Spontaneous gingival bleeding without provocation 2
  • Halitosis (foul breath) due to tissue necrosis 1
  • Pseudomembrane formation covering ulcerated areas 3

Secondary Clinical Features

  • Systemic manifestations including fever, malaise, and regional lymphadenopathy may be present 1, 2
  • Rapid onset and progression distinguishes ANUG from chronic periodontal disease 1, 4
  • Metallic taste reported by patients 3

Predisposing Factors to Assess

  • Immunocompromised status (HIV infection is a major risk factor) 1, 2
  • Psychological or physiological stress (historically common in military personnel) 2, 4
  • Poor oral hygiene and pre-existing gingivitis 2, 3
  • Malnutrition and poor living conditions 2, 3
  • Smoking and substance abuse 3

Microbiological Profile

  • Predominant anaerobic bacteria: Bacteroides intermedius and Fusobacterium species 2
  • Spirochetes are predominantly associated with the infection 3
  • Mixed aerobic/anaerobic infection with majority gram-negative organisms 2

Management Algorithm

Phase 1: Immediate Acute Phase Treatment (Day 1)

The primary goal is to halt disease progression immediately and control pain through gentle mechanical debridement combined with antimicrobial therapy. 1, 3

Local Mechanical Therapy

  • Gentle superficial debridement of necrotic tissue using ultrasonic scalers or hand instruments 3
  • Avoid aggressive scaling during acute phase as it increases pain and tissue trauma 5
  • Remove only loose necrotic tissue and superficial calculus 5, 3

Antimicrobial Mouthwash Therapy

  • 0.12% chlorhexidine gluconate mouthwash 10 mL twice daily as first-line antiseptic 5, 3
  • Dilute chlorhexidine by 50% if soreness is excessive 6
  • Hydrogen peroxide 1.5% mouthwash 10 mL twice daily as alternative antiseptic 6

Pain Management

  • Benzydamine hydrochloride oral rinse every 3 hours, particularly before eating 6, 7
  • Viscous lidocaine 2% (15 mL per application) for topical anesthesia if benzydamine insufficient 6, 7

Systemic Antibiotic Therapy

  • Metronidazole 400-500 mg three times daily for 3-5 days for severe cases with systemic involvement 3
  • Amoxicillin 500 mg three times daily as alternative or in combination for severe infections 3
  • Reserve antibiotics for cases with fever, lymphadenopathy, or extensive tissue involvement 3

Phase 2: Subacute Phase Treatment (Days 3-7)

Once acute symptoms subside, transition to more thorough mechanical therapy while maintaining antimicrobial support. 1, 5

  • Comprehensive scaling and root planing after acute inflammation resolves 5
  • Continue chlorhexidine rinses for 2-4 weeks total 5
  • Oral hygiene instruction with emphasis on gentle brushing technique 3
  • Nutritional counseling to address deficiencies 1

Phase 3: Treatment of Pre-existing Conditions (Weeks 2-4)

Address underlying chronic gingivitis or periodontitis that predisposed to ANUG. 1

  • Complete periodontal debridement of all quadrants 1
  • Professional prophylaxis every 2-4 weeks initially 5
  • Address modifiable risk factors including smoking cessation and stress management 1, 3

Phase 4: Surgical Correction (Months 2-3)

Surgical intervention is reserved only for persistent gingival craters that do not regenerate spontaneously. 5

  • Allow 6-8 weeks for spontaneous papillae regeneration before considering surgery 5
  • Gingivoplasty to eliminate residual craters only if conservative therapy fails 1, 5
  • Avoid premature surgical intervention as papillae may regenerate with periodic scaling and antimicrobial rinses alone 5

Phase 5: Maintenance (Ongoing)

Long-term maintenance prevents recurrence and ensures stable outcomes. 1

  • Professional cleanings every 3-4 months indefinitely 1
  • Daily chlorhexidine rinses during stress periods or illness 5
  • Monitor for recurrence at interdental papillae 1

Critical Pitfalls to Avoid

  • Do not perform aggressive debridement during acute phase as this increases pain and tissue damage 5, 3
  • Do not delay treatment as ANUG can progress to necrotizing ulcerative periodontitis (NUP) or noma without intervention 2
  • Do not perform elective surgery on acute lesions; wait for resolution and assess for spontaneous regeneration 5
  • Do not overlook systemic factors particularly HIV status in patients with severe or recurrent ANUG 1, 2
  • Do not prescribe antibiotics routinely for mild cases; reserve for severe infections with systemic involvement 3

Expected Outcomes

  • Ulcer healing within 3-7 days with adequate treatment 2
  • Complete resolution of acute symptoms within 1 week in most cases 3
  • Potential for papillae regeneration with conservative therapy avoiding surgical intervention 5
  • Recurrence risk remains if predisposing factors are not addressed 1, 3

References

Research

Necrotizing Ulcerative Gingivitis.

Contemporary clinical dentistry, 2017

Research

[NUG--necrotizing ulcerative gingivitis: a review].

Refu'at ha-peh veha-shinayim (1993), 2014

Research

Necrotising Ulcerative Gingivitis: A Literature Review.

Oral health & preventive dentistry, 2017

Research

The treatment of acute necrotizing ulcerative gingivitis.

Quintessence international (Berlin, Germany : 1985), 1991

Guideline

Guideline Directed Topic Overview

Dr.Oracle Medical Advisory Board & Editors, 2025

Guideline

Treatment of Frequent Mouth Ulcers in Senior Citizens

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

Have a follow-up question?

Our Medical A.I. is used by practicing medical doctors at top research institutions around the world. Ask any follow up question and get world-class guideline-backed answers instantly.