II. Indication
- Many antitoxins and antivenins are from horse serum (e.g. original Diphtheria antitoxin)
- Skin Test for Horse Serum Sensitivity prior to use
- Rarely performed now
III. Efficacy: General
- No study (including Skin Test for Horse Serum Sensitivity) predicts Serum Sickness reaction
IV. Efficacy: Controversial in Snake Antivenin (antivenom) use
- Previously indicated with older ACP antivenoms in which reactions were much more common
- Newer antivenoms (e.g. CroFab) have lower Incidence of reaction, and Skin Testing is not typically done
- Advantages to performing skin test prior to antivenin
- Possible medicolegal protection only
- Disadvantages to skin test prior to antitoxin
- Delays treatment (antitoxin administration)
- High false-positive rate: 33%
- High false-negative rate: 10 to 36%
- Has resulted in Anaphylaxis in some patients
- References
V. Technique
- 0.1 ml of 1:10 dilution of antitoxin intradermal
- Inject at Forearm with 27 gauge
VI. Evaluation: Observe for Allergic Reaction for 20 minutes
- Local reaction
- Hyperemic areola at injection site > 0.5 cm
- Systemic reaction
- Fever, chills
- Hypotension with decrease Blood Pressure >20 mmHg
- Skin rash
- Respiratory difficulty
- Nausea, Vomiting
- Generalized itching
VII. Interpretation: If any signs of reaction
- Suggests Horse Serum Sensitivity
- Do not use antitoxin