Systemic Reactions to brown recluse envenomations can lead to death. Those particularly susceptible to dying from these bites are children under the age of seven, the elderly, and those with severe underlying illnesses. Healthy adults are unlikely to die even if a systemic reaction occurs. However, the illness that can result is often long, debilitating and painful. It may take several months for even a healthy adult to fully recover from a systemic envenomation.

Systemic envenomation or loxoscelism develops 24 to 48 hours after the initial bite. Red blood cell destruction (hemolysis) can develop within 2 to 3 hours. Initially this may be unnoticed by patient but will ultimately result in flu-like symptoms (weakness, headache, malaise, perhaps light-headedness, and possibly fever).

Once the venom has spread through the body the patients condition may deteriorate rapidly. Patients responses to systemic loxoscelism may vary. The following is a general sequence of common events seen with systemic loxoscelism. The order, severity and sequence, of these events may vary from patient to patient.

Initially the patient may exhibit the signs and symptoms similar to those discussed earlier in the section on local reactions. As the toxin spreads systemic failures begin to occur.

As red blood cells are destroyed the nephrons of the kidneys begin to filter out the remnants of these damaged cells and the patient may notice what appears to be blood in the urine (very dark urine, possibly reddish brown in color. This is called hemoglobinuria). In some cases, particularly in children, this may ultimately result in kidney (renal) failure. The patient may soon cease to produce urine at all due to renal failure and dehydration. This dehydration comes from vomiting which may be so severe as to be difficult to manage. This too is often more pronounced in children.

As more and more red blood cells are destroyed, the general weakness and malaise the patient experiences will worsen and postural changes in blood pressure and pulse may occur (much as it does in the patient with dehydration or a GI bleed).

As the damage from the toxin continues, seizures may occur followed by coma (or vice-versa). Death, probably caused by hemolysis, may follow.

Remember that all of this can occur with 24 to 48 hours after the bite and that many patients do not even realize that they have been bitten. Of the patients who know that they have been bitten, many do not know that it was a brown recluse. I say this only as a reminder that in many cases where we (EMS) have been summoned, many hours may have passed since the bite occurred and this process may be well underway.

I would like to mention one further item that I found both disturbing and interesting. The Rash that is common in brown recluse bites may reoccur long after the envenomation. It has been known in rare cases to result in ulcerations of the skin away from the site of the envenomation in an almost random fashion. This phenomena however is not something we in EMS will usually see since it is usually seen days, and even weeks, after the bite (very rare). Some patients will complain of varied symptoms such as joint pain, rashes, ulcerations, headaches and fevers, weeks and even months after envenomation and treatment. Some say that these signs and symptoms occur at random and disappear as quickly as they occur.