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Acute Necrotizing Ulcerative Gingivitis (Trench Mouth)

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Acute Necrotizing Ulcerative Gingivitis (Trench Mouth)

4 min read


ANUG causes punched-out painful lesions or inflammation in the gums. Read the article to know the signs, symptoms, and management.

Medically reviewed by

Dr. Anuthanyaa. R

Published At June 15, 2021
Reviewed AtAugust 2, 2023

What Is ANUG?

Necrotizing ulcerative gingivitis or NUG is a specific form of gingival and periodontal disease, but when it has an acute clinical presentation in the gums with rapid onset and destruction, it is referred to as ANUG (Acute Necrotizing Ulcerative Gingivitis). Though not very common, the acute form of this microbial disease of the gingiva is a painful, destructive, and often ulcerative inflammation of the interdental tissue that is in between the gums (interdental papilla). ANUG hence if left untreated, progresses rapidly to:

  • Necrotizing Ulcerative Periodontitis - It is the destruction of the periodontal ligament and the underlying bone structure or alveolar bone, causing tooth mobility and tooth loss.
  • Cancrum Oris - It is a devastating and fatal form of orofacial gangrene infection.

ANUG is a non-communicable disease characterized by rapid destruction of the gum tissue or gingival tissue and may prove a dangerous infection in the context of immunocompromised patients in which the host immune response is impaired as in systemic disorders and diseases.

Why Is ANUG Called a Trench Mouth?

ANUG is also referred to as,

  1. Vincent's gingivitis.

  2. Vincent's infection.

  3. Vincent's angina.

This is because of the symbiotic microorganisms Borrelia Vincentii and Bacillus fusiformis. The condition is named after French physician Henri Vincent and the word "angina" is Latin derived, which means to" choke or throttle."

It is colloquially also known as "trench mouth." ANUG or NUG are both referred to colloquially as "Trench Mouth" that came into use from the times of World War I when the soldiers on the battlefield were affected by this severe gum infection because of:

What Is the Pathophysiology and Etiology of ANUG?

ANUG mainly affects the age group between 18-30 years in the younger adult population. ANUG has been documented by historians since the 4th century BC, even though it had a rare prevalence affecting less than 1% of the general population. The prevalence of this disease was particularly documented in young children with malnutrition or malnourishment deficiencies and in those patients with an immunodeficiency virus or HIV infection. The common physiologic factors that play a main role in compromising the immune defense of the oral cavity and the gingiva in ANUG is attributed to several factors like:

  1. Pre-existing gingivitis or gum disease.

  2. HIV infection.

  3. Tobacco usage.

  4. Poor diet (a most common cause of malnutrition) and insufficient sleep.

  5. Regular consumption of alcohol.

  6. Psychological stress.

  7. Poor oral hygiene.

These factors are known to not only alter the physiologic state of the gingiva by increasing the capillary permeability but also cause a reduction in the microcirculation of the gums and the salivary flow. So the oral immune response is compromised highly along with the facilitation of bacterial pathogenicity invading the gum tissue severely.

ANUG is mainly caused by the fusiform and spirochete bacterium. So it is considered by dental surgeons as an opportunistic dental infection because of the bacterial invasion. Spirochetes are identified as the majority of the gram-negative bacterium for causing this acute infection along with other gram-negative bacterial strains like Fusobacterium spp, Bacteroides intermedius, Prevotella intermedia, etc. These bacterial strains are usually identified in the gram staining method.

What Are the Symptoms of ANUG?

Timely recognition of this gum disease is crucial to prevent complications that may progress to the alveolar bone and the neighboring tissues of the cheek, lips, or jaw bone, resulting in the acute spread of infection.

Primary Symptoms

  1. Sudden or acute onset gum pain.
  2. Localized or generalized excruciating or intense pain in the interdental gingival tissue.

  3. Ulcerated crater-like lesions are a characteristic feature of this condition.

  4. Punched out appearances of the marginal or the interdental papilla are usually clinically confirmative.

  5. Bleeding gums or gingiva with or without provocation.

Secondary Features

  1. Fetid breath or foul breath or halitosis.

  2. Fever and generalized body fatigue or malaise.

  3. Regional or submandibular lymphadenopathy. Characteristic yellowish-white or grayish slough that is referred to as a "pseudomembrane" that covers the ulcerated gingival papillae.

  4. Intraorally, the dental surgeon may also observe pasty saliva and other acute features caused in the gingiva due to the rampant bacterial progression.

How Is ANUG Diagnosed?

ANUG can be diagnosed with IOPA (X-rays), and they may be made in specific regions of the mouth, or full mouth (OPG) or CBCT (3D imaging of specific regions of the teeth and bone). They are useful for assessing the treatment strategy and prognosis dentally. Blood tests may be suggested to detect potentially undiagnosed conditions like HIV infection and other immune deficiency issues that may be the main cause of bacterial aggression orally.

Differential Diagnosis:

The differential diagnosis is mainly based on the clinical features observed by the dentist upon intraoral examination. The differential diagnostic conditions for ANUG are:

  1. Primary herpetic gingivostomatitis.

  2. Desquamative gingivitis.

  3. Agranulocytosis.

  4. Cyclic neutropenia.

  5. Leukemia.

  6. Ascorbic acid deficiency or vitamin C deficiency.

  7. Pre-existing gingivitis turned into a chronic infection.

How Does a Dental Surgeon Manage ANUG?

Initial management includes the assessment of the gingival tissue destruction and comprehensive periodontal evaluation by the dentist to plan the treatment strategies. Patient counseling, antibiotic and painkiller therapy, and specific oral hygiene instructions along with antibacterial mouthwash prescriptions (such as Chlorhexidine gluconate rinse 0.12 % twice daily) will be an adjunct to the main surgical debridement by the dentist.

Under local anesthesia, the dental surgeon performs local debridement of the infected tissue by removal of the pseudomembrane of ANUG, and when any further signs of systemic involvement are suspected, the patient can be referred to a general physician to crosscheck the antibiotic therapy given. The recommended antibiotics are Amoxicillin and Metronidazole for mainline treatment of ANUG.

The dentist should assess treatment outcomes within 24 hours and every other day until the signs and symptoms of ANUG are resolved or rectified to an extent. If, after surgical debridement and antibiotic therapy, the issue still is non-resolved, it would signify involvement of underlying systemic or immunocompromised conditions or diseases. Hence it's essential for the dental surgeon to completely remove the source of irritation as incomplete debridement, or improper prophylaxis would lead to treatment failure.


ANUG can lead to the rampant destruction of the periodontium and the other tissues of the oral cavity if left untreated and can progress acutely to systemic complications. From the dentist's timely surgical intervention, the gums attachment loss can be resolved clinically over time with periodic oral prophylaxis, root planing, and antimicrobial rinses even after treatment.

Frequently Asked Questions


Is Acute Necrotizing Ulcerative Gingivitis Curable?

ANUG is curable. Debridement of the ulcerated gingiva, scaling, and root planing to remove calculus along with hydrogen peroxide mouth rinse, chlorhexidine mouthwash, and systemic antibiotics or painkillers if needed may be given.


Is Trench Mouth Serious?

Trench mouth is an extension of acute necrotizing ulcerative gingivitis. If left untreated, this necrotizing ulcerative periodontitis or trench mouth can further proceed to ulcerative necrotizing stomatitis, meaning the destruction of tissues of the mouth and cheeks exposing the bone.


Is ANUG Contagious?

Acute necrotizing ulcerative gingivitis is non-contagious, meaning it is not transmissible and does not spread from one person to another.


Does ANUG Cause Pain?

ANUG causes gum pain along with fever, bad breath, bleeding gums, and ulcerations.


Will My Trench Mouth Go Away?

The trench mouth is curable. Antimicrobials and painkillers are given to relieve the infection and pain. Ultrasonic deep scaling, root planing, wound debridement, hydrogen peroxide mouth rinse, and chlorhexidine mouthwash, along with proper oral hygiene practices, will relieve trench mouth.


What Does Trench Mouth Smell Like?

The trench mouth causes ulceration of the gums and the formation of yellowish to white or grayish pseudomembrane. All these, along with plaque and calculus cause oral malodor. A rotten egg smell or the smell of an infected wound can be presented.


What Does Trench Mouth Look Like?

Trench mouth is characterized by bad breath, altered taste, pus in the gums, bleeding gums, ulcerated gums, yellow or grayish membrane on the affected gums, rapidly progressing intense gum pain, lymph gland enlargement, and fever. In addition, there is the destruction of the underlying bone supporting the teeth.


Does Gingivitis Occur Suddenly?

Usual gingivitis due to plaque build-up and poor oral hygiene is a slow, gradual process. In conditions like acute necrotizing ulcerative gingivitis, sudden and rapid gingivitis occurs due to the body’s altered immune response.


Do Thrush and Trench Mouth Mean the Same?

Oral thrush and trench mouth are different. Oral thrush is caused due to fungal infection; typically, a candidal infection and trench mouth are caused by an impaired immune response to pathogenic microbes in the mouth.


Which Body Part Gets Affected by Acute Necrotizing Ulcerative Gingivitis?

ANUG affects the gingiva, especially the gum that is present in between two teeth. If left untreated, it progressively affects the underlying bone, further destroying and necrotizing the soft tissues to expose the surrounding bone.


When Will My Acute Gingivitis Heal?

With proper systemic and oral treatment and good oral hygiene procedures, acute necrotizing gingivitis can heal within weeks.


How Are Necrotizing Ulcerative Periodontitis Treated?

The lesions are debrided under local or topical anesthesia. Initially, the affected areas are swabbed with cotton to remove the pseudomembrane and debris. Then it is cleansed with warm water. Ultrasonic scaling and root planing are done to remove the calculus. Profuse irrigation leads to debridement of the deep lesions. Chlorhexidine mouthwash is recommended for daily use. Antimicrobials and painkillers are advised, along with management of the underlying systemic conditions.


Which Antibiotics Cure Necrotizing Ulcerative Gingivitis?

Metronidazole, Amoxicillin, Erythromycin, Doxycycline, Tetracycline, and Clindamycin are effective antibiotics for necrotizing ulcerative gingivitis.
Dr. Achanta Krishna Swaroop
Dr. Achanta Krishna Swaroop



halitosisperiodontal gum diseasetrench mouthanugbleeding gums
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