What causes a metallic taste of blood?

Causes of Tasting Blood

The most common causes of a metallic or blood taste in the mouth include bleeding from the oral cavity, upper respiratory tract, or sinuses, with specific causes including dental issues, sinus disease, respiratory infections, and certain medications or systemic conditions 1, 2.

Common Sources of Blood Taste

Oral and Dental Causes

• Gingival bleeding from periodontal disease
• Dental work or trauma (should avoid saliva sampling within 1-2 hours of dental work) 1
• Angina bullosa hemorrhagica (benign blood-filled blisters in the mouth that rupture) 3
• Tooth trauma or sharp dental edges causing microtrauma to oral tissues

Upper Respiratory Tract Causes

• Post-nasal drip with blood components (may indicate paranasal sinus disease) 2
• Epistaxis (nosebleed) with posterior drainage
• Upper respiratory tract infections causing inflammation and microbleeding
• Sinusitis with blood-tinged secretions

Systemic Conditions

• Hemoglobinopathies (like methemoglobinemia) that can cause altered taste perception 4
• Medication side effects (particularly antibiotics like amoxicillin can cause taste alterations) 5
• Coagulation disorders causing minor oral bleeding that may be perceived as a blood taste 6

Diagnostic Approach

Key History Elements

1. Timing and duration of the taste
2. Associated symptoms (nasal congestion, cough, headache)
3. Recent dental work or oral trauma
4. Medication use (especially antibiotics, steroid inhalers)
5. History of sinus disease or respiratory infections

Physical Examination Focus

1. Thorough oral cavity examination for sources of bleeding
2. Nasal examination for evidence of epistaxis or blood-tinged discharge
3. Oropharyngeal examination for post-nasal drip

When to Be Concerned

A blood taste requires more urgent evaluation when accompanied by:

• Hemoptysis (coughing up blood) 7
• Significant epistaxis that doesn't resolve with pressure
• Blood-tinged post-nasal drip in older adults (50% may have conditions other than sinusitis, including potential malignancy) 2
• Systemic symptoms like fever, weight loss, or night sweats

Management Approach

1. For oral sources:

   • Dental evaluation for sharp edges or periodontal disease
   • Oral hygiene optimization
   • Avoidance of irritating foods (spicy foods, alcohol) 8

2. For nasal/sinus sources:

   • Nasal saline irrigation
   • Room humidification (beneficial for epistaxis) 8
   • Evaluation for underlying sinus disease

3. For medication-related taste disturbances:

   • Review medication list for potential culprits
   • Consider medication changes if appropriate

Prevention Strategies

• Maintain good oral hygiene
• Avoid irritating foods and beverages (alcohol, spicy foods) 8
• Adequate hydration and room humidification
• Regular dental check-ups to address sharp edges or periodontal issues

Special Considerations

Blood taste perception without visible bleeding may indicate:

• Very small amounts of blood mixing with saliva
• Altered taste perception due to medications
• Sinus drainage occurring during sleep that isn't noticed
• Metallic taste misinterpreted as blood (common with certain medications)

If the blood taste persists beyond 2 weeks or is accompanied by other concerning symptoms, further evaluation with imaging studies or specialty referral may be warranted.