Serum sickness following administration of Antivenin (Crotalidae) Polyvalent in 181 cases of presumed rattlesnake envenomation.

OBJECTIVE:

To describe the incidence and characteristics of serum sickness (SS) following administration of Wyeth Antivenin (Crotalidae) Polyvalent (ACP).

METHODS:

A retrospective chart review was conducted involving presumed rattlesnake bite victims referred to our poison center. Serum sickness was defined as unexplained rash developing 3 to 21 days following the administration of ACP. Patients were monitored until complete resolution of all symptoms. Data collected included total number of ACP vials administered, associated signs and symptoms, duration of signs and symptoms, and medications used to treat SS.

RESULTS:

Of the 181 cases included in our study, SS occurred in 102 (56%) patients. The frequency of SS in patients receiving fewer than 20, 20 to 29, 30 to 39, or 40 or more vials was 34%, 36%, 88%, and 100%, respectively. Duration of SS averaged 6.1 days (range, 1-21 days). Associated symptoms included subjective fever (49%), arthralgia (20%), and pruritus (40%). Reported medications used included prednisone (98%), antihistamines (92%), and histamine-2 blockers (3%).

CONCLUSIONS:

Serum sickness following administration of Wyeth ACP is common, with a strong correlation between ACP dosage and SS frequency.