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07-14-14 What is the life threat of Systemic Loxsoscelism?

Question of the Week

July 14, 2014

What is the life threat of Systemic Loxsoscelism?

We are familiar with the cutaneous lesions following brown recluse spider bite (BRSB). Central necrosis can occur although the bites usually heal very well if they are left alone.  No ointments, no debridement, no dapsone.  Ice works better than opiates for the pain. Hard for physicians to do nothing.

But Systemic loxsoscelism may also occur following BRSB.  The syndrome consists of fever, rash, myalgia, and hemolysis.  Why it occurs in some people with a BRSB and not in others is unknown.  Toxin-induced hemolysis can occur very rapidly and therein lies the life threat-especially in children. The majority of the reported deaths have occurred in children as a result of rapid hemolysis.  The difficulty is in determining which children with a cutaneous lesion will develop systemic loxsoscelism. Therefore, a cautious clinical approach is necessary.

Our recommendations are that all children under 12 years of age with a BRSB should have a urine dipped to test for the presence of hemoglobin/blood.  If the urine dip is positive for blood and/or the patient has other signs of systemic loxsoscelism (rash,fever), the patient should be admitted to be observed for hemolysis.  If the urine dip is negative, and there are no other signs of systemic loxsoscelism, the child should be seen by a physician the next day. If adults with a BRSB do not have signs of systemic loxsoscelism, there is no need to dip a urine. 

And remember, if you have questions about a patient with a BRSB, call the poison center.

Question prepared by:  Donna Seger, MD  Medical Toxicologist

We have recently seen a number of patients with BRSB – the spiders are very busy this year. 

This Question was requested by one of our readers.