Rabies Immunoglobulin (RIG) Dose in Dog Bite

Types and Doses

Indications

• Category III: Single or multiple transdermal bites/scratches, licks on broken skin, exposure of mucous membranes to saliva, contact with bats.
• Category II: Nibbling of uncovered skin, minor scratches/abrasions without bleeding - RIG added only in immunocompromised individuals.

RIG is NOT given to previously vaccinated individuals - they only need 2 vaccine doses on days 0 and 3.

How to Administer

1. Infiltrate locally into and around the bite wound(s) - as much as anatomically possible. This is the primary protective measure.
2. Remaining volume (if any) - inject IM at a site distant from the vaccine injection site.
3. RIG may be diluted with normal saline to allow sufficient volume to infiltrate all wound sites.
4. Administer only once, ideally on Day 0 (same day as first vaccine dose).
5. Do NOT give beyond Day 7 of post-exposure prophylaxis - by then, active immunity from the vaccine is assumed to have developed.

Key Points

• HRIG is of human origin - negligible risk of allergic reactions; more expensive.
• ERIG is of equine (horse) origin - small risk of anaphylaxis (~1/45,000 cases); considerably cheaper. A skin test before ERIG is not recommended because it does not predict reactions and ERIG should be given regardless.
• Never inject RIG into the same anatomical site as the vaccine.
• For wounds that cannot be infiltrated (e.g., fingertip), inject as close to the site as possible.
• In immunocompromised patients, RIG + 5-dose IM vaccine regimen is mandatory for Category II and III exposures.