From the Guidelines
The most consistent symptom of envenomation by Loxosceles sp. is the development of a necrotic eschar. This is based on the latest guidelines from the American Heart Association and American Red Cross, which state that bites from brown recluse and related spiders (genus Loxosceles) cause painful ulcerated wounds that progress over days to weeks, sometimes associated with hemolysis and rhabdomyolysis 1. The development of a necrotic eschar is a hallmark of brown recluse spider envenomation, and it is the most reliable diagnostic feature.
Some key characteristics of the necrotic eschar include:
- A small red or purple area that develops within 2-8 hours after the bite
- Mild pain or stinging
- Evolution into a "red, white, and blue sign" - a central pale area of ischemia (white) surrounded by a ring of erythema (red) and a larger outer ring of bluish discoloration
- Progression to form an eschar (black scab) and eventually a necrotic ulcer that can take weeks to months to heal
While other symptoms like abdominal rigidity, disseminated intravascular coagulation (DIC), and respiratory failure can occur in some cases, they are not as consistent or reliable as the development of a necrotic eschar. Systemic symptoms like fever, chills, nausea, and joint pain can also occur, but the localized necrotic skin lesion remains the most characteristic feature of brown recluse envenomation 1.
From the Research
Symptoms of Loxosceles Envenomation
The symptoms of envenomation by Loxosceles sp. can vary, but some are more consistent than others. The options provided are:
- Abdominal rigidity
- Disseminated intravascular coagulation (DIC)
- Necrotic eschar
- Respiratory failure
Most Consistent Symptom
Based on the available evidence, the most consistent symptom of envenomation by Loxosceles sp. is:
- Necrotic eschar, as it is frequently mentioned in the studies as a characteristic skin lesion resulting from the bite 2, 3, 4, 5, 6 Other symptoms such as disseminated intravascular coagulation (DIC) and systemic inflammatory response syndrome are also possible, but necrotic eschar is the most directly associated with the bite itself 2, 4, 5.
Systemic Symptoms
Systemic symptoms can occur, including: