I wish I knew. Especially this summer when these spiders seem to be overtaking us.
There are two types of loxoscelism-cutaneous (Brown Recluse Spider Bite(BRSB)) and cutaneous-hemolytic (patients with the cutaneous lesion that develop hemolysis that may be life-threatening). Constitutional symptoms may be present in both cutaneous and cutaneous-hemolytic loxoscelism.
Treatment of cutaneous BRSB has been dealt with in a previous Question of the Week. Basically, don’t cut and don’t use ointment. Ice for pain. The bites heal well if one can keep them out of the vision of surgeons.
But the identification of patients with the bite who will hemolyze is still difficult. Until recently, we tested for hemolysis by dipping the urine in anyone with a fever and a rash. When the urine dipped positive for blood without red cells, intravascular hemolysis was diagnosed. But this retrospective study demonstrated that about 25% of patients suffered extravascular hemolysis (so urines were normal). Spherocytosis was present in many with extravascular hemolysis, but a blood smear was not obtained in all patients. What a wake-up call!
The study is small and retrospective, so few conclusions can be made. Patients in this study developed hemolysis within a week of the bite. (We have seen patients prior to this study that developed hemolysis 10-12 days after the bite.)
The main point of this Question is to make you aware of the possibility of extravascular hemolysis.
I have attached the new protocol for loxoscelism which has been developed and approved by representatives from Vanderbilt Pediatrics, PICU, MICU, Peds ED, Adult ED, and Toxicology.
Prepared by Donna Seger, MD
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Donna Seger, MD
Tennessee Poison Center
Poison Help Hotline: 1-800-222-1222