Is tetanus prophylaxis required for spider bites?

Tetanus Prophylaxis for Spider Bites

Tetanus prophylaxis is not routinely required specifically for spider bites, but should be administered based on the wound characteristics and the patient's immunization status according to standard wound management guidelines. 1, 2, 3

Classification of Spider Bites for Tetanus Risk

• Spider bites are classified as "non-clean wounds" that may be contaminated with dirt, saliva, or other materials, similar to puncture wounds 3
• The Centers for Disease Control and Prevention (CDC) considers wounds contaminated with dirt, soil, or saliva to carry a higher risk of tetanus infection 2

Tetanus Prophylaxis Guidelines Based on Immunization Status

For Patients with Complete Primary Series (≥3 doses):

• If last tetanus toxoid-containing vaccine was <5 years ago: No tetanus prophylaxis needed 1
• If last tetanus toxoid-containing vaccine was ≥5 years ago: Administer tetanus toxoid-containing vaccine without TIG (tetanus immune globulin) 1, 4

For Patients with Unknown or Incomplete Immunization (<3 doses):

• Administer tetanus toxoid-containing vaccine AND tetanus immune globulin (TIG) immediately, using separate syringes at different anatomical sites 1, 2, 4

Vaccine Selection Guidelines

• For persons aged ≥11 years who have not previously received Tdap or have unknown Tdap history: Tdap is preferred over Td 1
• For nonpregnant persons with documented previous Tdap vaccination: Td should be used 1
• For pregnant women requiring tetanus prophylaxis: Tdap should be used regardless of prior Tdap history 1, 3
• If Td is unavailable, Tdap may be administered regardless of prior Tdap history 1

Special Considerations

• Persons with HIV infection or severe immunodeficiency who have contaminated wounds should receive TIG regardless of their tetanus immunization history 1, 2
• When both TIG and tetanus toxoid-containing vaccine are indicated, they must be administered at different anatomical sites to avoid interference 2, 4
• Persons with a history of an Arthus reaction following a previous tetanus toxoid-containing vaccine should not receive a tetanus toxoid-containing vaccine until >10 years after the most recent dose 3

Wound Management for Spider Bites

• All spider bites should be thoroughly cleansed and tetanus status updated as needed 5
• Tetanus prophylaxis should be administered according to the standard wound management guidelines, not specifically because it's a spider bite 5, 6

Clinical Pearls and Pitfalls

• Do not assume spider bites are "clean wounds" - they should be treated as potentially contaminated wounds requiring appropriate tetanus prophylaxis 3
• It is not possible to clinically determine which wounds are tetanus-prone, as tetanus can occur after minor injuries yet is rare after severely contaminated wounds 7
• There is no urgency for the administration of tetanus toxoid in the acute setting, as it provides protection against future injuries, not the current injury 7