Brown recluse envenomation can cause delayed hemolysis and DIC in children. Learn how to distinguish it from other bites on boards.
Systemic brown recluse envenomation in children can present with “flu-like” symptoms followed by hemolysis and DIC—an exam-favorite pattern recognition task.
A 12-month-old boy presents to the ED after developing flu-like symptoms. Parents noted fever, chills, nausea and vomiting, and weakness. On examination, you notice petechiae. Laboratory findings demonstrate acute hemolysis, DIC, and rhabdomyolysis.
Which envenomation can lead to these complications?
Answer Options:
A. Agkistrodon (copperhead)
B. Heloderma horridum (beaded lizard)
C. Loxosceles (brown recluse)
D. Megalopyge (puss caterpillar)
The keyed answer (Loxosceles) is consistent with current exam-relevant consensus: systemic loxoscelism can cause delayed constitutional symptoms and severe systemic toxicity including intravascular hemolysis and DIC, particularly in pediatric patients (Wilderness Medical Society Practice Guidelines, 2016; Goldfrank’s Toxicologic Emergencies, 2019). Petechiae in this stem fits DIC/thrombocytopenia physiology. Rhabdomyolysis is less “signature” than hemolysis/DIC but is described among severe systemic toxic effects in case-based toxicology literature and is compatible with a severe systemic envenomation illness script.
Boards often test that brown recluse is not only a necrotic wound: the high-risk, time-delayed systemic syndrome (often 24–72+ hours after bite) is the key discriminator.
| Option | What It Tests / Implies | Why It’s Wrong Here |
| Agkistrodon (copperhead) | Pit viper envenomation → coagulopathy, local tissue injury | Copperhead bites are typically less severe; while pit vipers can cause coagulopathy, this stem’s hemolysis + DIC pattern is classically tested with loxoscelism rather than copperhead. |
| Heloderma horridum (beaded lizard) | Venomous lizard bite | Typically causes local pain, edema, and systemic symptoms (e.g., hypotension) are uncommon; not the classic hemolysis/DIC syndrome in boards. |
| Loxosceles (brown recluse) | Systemic loxoscelism | Best match: delayed flu-like symptoms with intravascular hemolysis and DIC, especially in children (WMS 2016; Goldfrank 2019). |
| Megalopyge (puss caterpillar) | Caterpillar setae toxin dermatitis | Causes localized pain/dermatitis; does not cause hemolysis/DIC/rhabdomyolysis. |
In a child with delayed “flu-like” illness plus hemolysis and DIC, think systemic loxoscelism (brown recluse) even if a dramatic necrotic lesion is not emphasized.
This item rewards syndrome recognition: “flu-like prodrome + petechiae + hemolysis/DIC” points to toxin-mediated hematologic catastrophe rather than a purely local bite reaction. The distractors are “well-known” exposures, but only one is consistently associated with delayed hemolysis/DIC on exams.
A 6-year-old develops fever, malaise, and dark urine 48 hours after a suspected spider bite. Labs show falling hemoglobin, elevated LDH, and indirect hyperbilirubinemia. What is the most likely culprit?
Which complication is most classically associated with systemic loxoscelism in children?
A teen presents with severe muscle cramping, abdominal pain, diaphoresis, and hypertension after a spider bite; labs show no hemolysis. Which is most likely?
A 4-year-old with suspected systemic loxoscelism has hemoglobin drop and signs of coagulopathy. Best next step in ED management?
A patient has immediate burning pain and erythematous papules in a “tram-track” pattern after contact with a fuzzy caterpillar; no systemic abnormalities. Most likely exposure?
How would you distinguish systemic loxoscelism from meningococcemia or other septic petechial illnesses in a child when the history of a bite is uncertain, and what minimum lab monitoring would you order?
Q1: What is the single most board-relevant systemic complication of brown recluse bite in children?
A: Hemolysis with possible DIC; the ABIM/ABP-style framing expects recognition of delayed intravascular hemolysis rather than only a necrotic lesion (WMS 2016).
Q2: Does every brown recluse bite cause skin necrosis?
A: No. Many are mild; boards test that systemic loxoscelism can occur even when the skin findings are not dramatic.
Q3: Is dapsone standard therapy for brown recluse bites?
A: No. Contemporary guidance emphasizes supportive care; dapsone is not routine due to limited evidence and adverse effects (WMS 2016).
Q4: What “look-alike” toxidrome should you contrast with loxoscelism?
A: Latrodectism (black widow)—prominent muscle cramps and autonomic symptoms without the hemolysis/DIC pattern.
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