What causes fever with gum redness and swelling, potentially indicating an oral infection such as gingivitis or periodontitis, in a patient with possible history of dental problems or immunocompromised status?

Fever with Gum Redness and Swelling: Causes and Diagnostic Approach

Primary Cause

The most common cause of fever with gum redness and swelling is acute periodontal infection (gingivitis progressing to periodontitis with systemic involvement), but you must immediately rule out infective endocarditis, which represents a life-threatening complication of oral bacterial seeding. 1, 2

Infectious and Local Causes

Periodontal Disease Progression

• Poor oral hygiene leading to bacterial plaque accumulation is the primary driver, causing gingivitis (gum inflammation with bleeding) that can progress to periodontitis (destruction of bone and connective tissue support). 1, 3, 4
• The bacterial biofilm contains specific pathogenic species including Streptococcus, Fusobacterium, Actinomyces, Veillonella, Treponema, Bacteroides, and Capnocytophaga that trigger both local inflammation and potential systemic bacteremia. 5, 6
• When fever accompanies gum inflammation, this signals systemic bacterial dissemination or abscess formation, requiring urgent evaluation. 2, 7

Acute Complications

• Untreated gingivitis/periodontitis can progress to pulpal necrosis, localized periodontal abscess, or deep space infections extending to cervicofacial tissues. 2, 7
• Periodontal abscesses present with localized pus collection, pain, and fever, representing acute exacerbations requiring immediate intervention. 8, 7

Critical Life-Threatening Cause to Rule Out

Infective Endocarditis

• Poor oral hygiene and periodontal diseases are responsible for the vast majority of oral-origin infective endocarditis cases, not dental procedures. 1, 2
• The strong association between periodontal inflammation and bacteremia from IE-related species (viridans group streptococci, Aggregatibacter actinomycetemcomitans) makes this diagnosis critical. 1
• Obtain at least 3 sets of blood cultures BEFORE initiating any antibiotics to avoid culture-negative endocarditis. 2
• Never prescribe antibiotics for undefined febrile illness without obtaining blood cultures first. 2

Systemic and Medication-Related Causes

Drug-Induced Gingival Hyperplasia with Secondary Infection

• Calcium channel blockers and cyclosporine A cause gingival enlargement that predisposes to bacterial colonization and infection. 1, 2
• Consider switching cyclosporine to tacrolimus if drug-induced hyperplasia is identified, as tacrolimus does not cause this side effect. 1, 2

Immunocompromised States

• HIV, chemotherapy, diabetes mellitus, and chronic kidney disease increase risk of opportunistic infections and poor wound healing. 3, 2
• Diabetes causes both periodontal disease and predisposes to secondary infections through immunosuppression and altered oral flora. 3

Nutritional and Autoimmune Conditions

• Sjögren's syndrome causes xerostomia leading to gingivitis and secondary infections. 3
• Nutritional deficiencies (B vitamins, iron) manifest with bleeding gums and increased infection susceptibility. 3

Immediate Diagnostic Algorithm

Step 1: Obtain Blood Cultures First

• Draw 3 sets of blood cultures before any antibiotic administration. 2
• This single step prevents diagnostic disaster in potential endocarditis cases. 2

Step 2: Comprehensive Oral Examination

• Inspect for periodontal inflammation, pocketing around teeth, caries that may cause pulpal infection, and signs of abscess formation. 1, 2
• Assess for trauma sources including ill-fitting prostheses and fractured teeth. 2
• Obtain full-mouth intraoral radiographs to identify caries, periodontal bone loss, tooth fractures, and occult pathology. 1, 2

Step 3: Cardiac Evaluation

• Obtain echocardiography to evaluate for infective endocarditis given the strong association between periodontal disease and IE. 2
• This is non-negotiable in any patient with fever and periodontal infection. 2

Step 4: Laboratory Assessment

• Complete blood count to assess for leukopenia (infection risk) or leukocytosis (active infection). 2
• Inflammatory markers (ESR, CRP) if systemic involvement suspected. 2
• Fasting glucose or HbA1c to screen for diabetes. 3
• Consider iron studies, B12, folate if nutritional deficiency suspected. 3

Step 5: Medication Review

• Review for cyclosporine and calcium channel blockers as causes of gingival hyperplasia with secondary infection. 2
• Assess for immunosuppressants, corticosteroids, and other medications affecting immune function. 3

Risk Stratification for Hospitalization

Admit immediately if any of the following are present:

• Systemic involvement with fever and lymphadenopathy. 2
• Suspected infective endocarditis based on clinical presentation. 2
• Immunocompromised status. 2
• Deep space infection or cervicofacial tissue involvement. 2

Critical Pitfalls to Avoid

• Never dismiss fever with gum inflammation as "just gingivitis"—this combination signals systemic bacterial dissemination or endocarditis until proven otherwise. 2
• Never start empirical antibiotics before blood cultures, as this creates culture-negative endocarditis and diagnostic confusion. 2
• Do not prescribe antibiotics without proper surgical intervention for dental abscesses, as this leads to treatment failure. 2
• Do not overlook infective endocarditis in patients with fever and periodontal disease, as delayed diagnosis has catastrophic consequences. 2