What is the effect of aspirin (acetylsalicylic acid) on cold sores?

Aspirin Has No Beneficial Effect on Cold Sores and May Worsen Them

Aspirin should not be used for cold sores as it may potentially worsen the condition and has no proven benefit for herpes simplex virus infections. While aspirin is commonly used for various conditions, it is not recommended for treating cold sores (herpes labialis).

Mechanism and Effects

Aspirin (acetylsalicylic acid) works primarily through:

• Inhibition of cyclooxygenase enzymes (COX-1 and COX-2)
• Anti-inflammatory and antipyretic effects
• Antiplatelet activity

However, for cold sores specifically:

• No clinical guidelines recommend aspirin for cold sores
• The European Society of Clinical Microbiology and Infectious Diseases' guideline for sore throat management does not include aspirin as a specific treatment for viral lesions like cold sores 1
• Aspirin may actually interfere with normal wound healing processes, which could potentially delay cold sore resolution 2

Potential Risks of Aspirin for Cold Sores

1. Increased Bleeding Risk:

   • Aspirin's antiplatelet effects may increase bleeding at the site of the cold sore
   • This could potentially delay healing and increase discomfort

2. Irritation:

   • Direct application of aspirin to cold sores can cause chemical irritation
   • May worsen inflammation at the site of the lesion

3. Reye's Syndrome Risk:

   • Particularly important in children and teenagers with viral infections
   • Potentially life-threatening condition associated with aspirin use during viral illnesses

Better Alternatives for Cold Sores

According to current guidelines, more appropriate treatments include:

1. Antiviral Medications:

   • Topical or oral acyclovir, valacyclovir, or famciclovir
   • These directly target the herpes virus causing cold sores

2. Recommended Pain Relief:

   • Acetaminophen (paracetamol) is preferred for pain relief during viral infections 3
   • Ibuprofen may be used as an alternative and has been shown to be better tolerated than aspirin for cold/flu symptoms 4

3. Supportive Care:

   • Keeping the area clean and dry
   • Cold compresses for comfort
   • Avoiding triggers that may cause recurrence

Special Considerations

• Patients on Aspirin Therapy: Patients already taking low-dose aspirin for cardiovascular protection should continue their prescribed regimen but should not use additional aspirin specifically for cold sores 1

• Wound Healing: Research suggests that while aspirin may have beneficial effects in some chronic wounds, herpes lesions are acute viral infections where aspirin's effects on cyclooxygenase enzymes may impair normal healing 2

• Antiviral Properties: While one study suggested aspirin may have some in vitro antiviral activity against certain respiratory viruses 5, this has not been demonstrated clinically for herpes simplex virus, and the potential negative effects on healing outweigh any theoretical benefit

In conclusion, aspirin should be avoided for treating cold sores. Patients should instead use approved antiviral medications and acetaminophen for pain relief if needed.